---

NICU Consultant Ward Round Viva

Neonatal Arterial Ischemic Stroke with Refractory Seizures

---

[Attending Neonatologist walks into the unit. Registrar is presenting at the bedside of a term neonate on Day 2 of life, oxygen saturation probe on, aEEG running, IV access in situ.]

---

SECTION 1 - PRESENTATION

---

---

---

---

---

EXAMINER'S CRITIQUE

"This is a previously well term neonate, Day 2 of life, with no antenatal or perinatal red flags documented yet, presenting with acute-onset focal clonic seizures restricted to the left upper limb - a lateralizing, motor-predominant semiology - in the absence of HIE, metabolic derangement, or structural anomaly on prior imaging, whose MRI now demonstrates findings consistent with acute arterial ischemic stroke, and who has failed first-line levetiracetam, now requiring second-line therapy with lacosamide."

1. Characterizing the baby - term, previously well, no HIE context
2. Characterizing the seizure - focal clonic, left UL, lateralizing
3. Excluding the common - no HIE, metabolic cause, structural malformation
4. Framing the pivot - MRI confirms NAIS
5. Stating the clinical problem - refractory seizures requiring escalation

---

COMPLETE FELLOWSHIP-LEVEL NICU WARD ROUND VIVA

Neonatal Arterial Ischemic Stroke | Term Neonate | Day 2 of Life

Academic Tertiary NICU Format - Question + Ideal Consultant Answer

---

---

SECTION 1: PRESENTATION

---

Q1. Give a one-minute problem representation of this baby.

IDEAL CONSULTANT ANSWER

"This is a previously well term neonate, Day 2 of life, born at term gestation with no documented antenatal complications, presenting with acute-onset focal clonic seizures confined to the left upper limb - a lateralizing, motor-predominant semiology - in the absence of features suggesting hypoxic-ischemic encephalopathy, metabolic derangement, or prior structural anomaly. The MRI brain demonstrates findings consistent with acute neonatal arterial ischemic stroke, most likely in the territory of the right middle cerebral artery. The seizures have failed first-line levetiracetam and now require second-line lacosamide, meeting criteria for refractory neonatal seizures. The key clinical problems are: (1) seizure control, (2) identification of stroke etiology, and (3) neuroprotection and neurodevelopmental surveillance."

• Characterizes the baby (term, previously well, no HIE context)
• Semantic qualifier on semiology (focal clonic, lateralizing, left UL)
• Excludes common mimics proactively
• Names the territory from the MRI
• Frames the two active clinical problems
• Does not just recite facts - synthesizes

---

Q2. What is your full differential diagnosis BEFORE the MRI result?

IDEAL CONSULTANT ANSWER

• Term baby (not preterm), previously well, no perinatal asphyxia
• Day 1-3 onset (classical window for NAIS)
• Strictly unilateral focal clonic semiology
• No fever, no CSF pleocytosis, no metabolic derangement

---

Q3. What does the seizure semiology tell you anatomically? Localize the lesion from the semiology alone, before looking at the MRI.

IDEAL CONSULTANT ANSWER

1. Contralateral hemisphere involvement - clonic movements of the left hand/arm localizes to the right cerebral hemisphere. This is the fundamental principle of contralateral motor control via the corticospinal tract.
2. Primary motor cortex (M1) involvement - The motor homunculus places the hand and upper limb representation in the lateral convexity of the precentral gyrus (Brodmann area 4), specifically the region supplied by the upper division of the right middle cerebral artery (MCA).
3. Clonic vs tonic - Clonic semiology implies repetitive cortical discharge from irritative cortex (ictal zone in peri-infarct penumbra). Tonic would imply deeper/subcortical involvement.
4. Strictly focal - no Jacksonian march described - Suggests focal cortical irritation without spread. A Jacksonian march (thumb → hand → arm → face) would still localize to M1 but would imply larger cortical involvement.
5. Localization summary: Right hemisphere, lateral convexity, precentral gyrus, hand-arm area, upper MCA territory = right MCA infarct is the most anatomically coherent explanation.

---

---

SECTION 2: NEONATAL SEIZURES

---

Q4. Classify neonatal seizures according to the ILAE 2021 classification. How does this differ from the older Volpe classification?

IDEAL CONSULTANT ANSWER

ILAE 2021 Classification:

• The old Volpe classification (1989, revised 2008) categorized seizures as: subtle, clonic (focal/multifocal), tonic (focal/generalized), myoclonic (focal/multifocal/generalized)
• The ILAE 2021 eliminates "subtle seizures" as a seizure type - recognizing that most "subtle" behaviors (cycling, rowing, swimming, chewing, eye deviation) are non-epileptic motor automatisms that are NOT EEG-correlated
• ILAE 2021 emphasizes that clinical diagnosis of neonatal seizures is unreliable - EEG confirmation is mandatory
• The concept of electroclinical dissociation is formally recognized

• Electroclinical seizure - EEG ictal discharge + clinical manifestation
• Electrographic-only (subclinical) seizure - EEG ictal discharge, no clinical correlate
• Clinical-only (behavioral) event - Clinical paroxysmal event, NO EEG correlate = NOT a seizure

---

Q5. What is electroclinical dissociation? Why does it occur in neonates, and why is it especially relevant after antiseizure medication?

IDEAL CONSULTANT ANSWER

1. Subclinical (electrographic-only) seizures - EEG shows ictal discharges but no visible clinical behavior
2. Uncoupling after treatment - After loading with phenobarbitone or levetiracetam, the clinical seizure stops but the EEG ictal discharge continues - the drug suppresses motor expression without suppressing the underlying epileptic discharge

1. Immature corticospinal tract - The cortex is generating ictal discharge but cannot propagate it to motor neurons because of poor myelination and synaptic connectivity. The discharge stays cortical.
2. Subcortical seizure generation - Many neonatal seizures arise in subcortical structures (thalamus, brainstem) where clinical output is primarily autonomic - you see apnea, not clonic movements.
3. Drug-induced uncoupling - Phenobarbitone acts on GABA-A receptors; it suppresses behavioral manifestations (consciousness, motor) more effectively than it suppresses the cortical ictal discharge. This is well-documented - after phenobarbitone loading, 85% of clinical seizures stop but only 55% of electrographic seizures stop (Painter et al., 1999, NEJM).

• The baby had focal clonic seizures - you MUST confirm EEG correlation
• After levetiracetam loading, the visible clonic activity may stop but electrographic seizures may continue
• Without continuous EEG, you are managing blindly - a baby may appear seizure-free while electrographic status epilepticus continues
• This is why ILAE 2023 guidelines state EEG monitoring is essential in any neonate with suspected seizures and in all neonates after a first ASM dose

---

Q6. Why are neonatal seizures predominantly focal rather than generalized?

IDEAL CONSULTANT ANSWER

• The peri-infarct penumbra has ischemia-induced neuronal hyperexcitability due to glutamate release, ionic shifts (Na⁺ in, K⁺ out), and failure of Na-K-ATPase
• This creates a focal irritative cortex at the border zone of infarction
• The core infarct is electrically silent; the penumbra generates ictal discharges
• The seizure localizes precisely to the cortical territory of the injured vessel - left hand seizure = right MCA infarct

---

Q7. Define neonatal status epilepticus. What is the EEG criteria? Is it the same as in adults?

IDEAL CONSULTANT ANSWER

1. Single electrographic seizure lasting >30 minutes (most widely used EEG criterion)
2. Cumulative seizure burden >50% of any one-hour epoch on continuous EEG
3. Electrographic status epilepticus (ESE) = continuous ictal activity >10 minutes or recurrent seizures >50% of the EEG record (American Clinical Neurophysiology Society, ACNS 2015 and updated 2021)

• Neonates may have brief electrographic seizures (30-90 seconds) that are individually short but collectively constitute high seizure burden
• Seizure burden (total minutes of electrographic seizure activity per hour) is the most clinically meaningful metric
• Studies (Glass et al., 2009; Srinivasakumar et al., 2015) show that high seizure burden correlates directly with worse neurodevelopmental outcome, independent of the underlying etiology

• <10 minutes/hour - low burden
• 10-30 minutes/hour - moderate burden

• 30 minutes/hour - high burden (associated with worse MRI injury and outcomes)

• 50 minutes/hour = status epilepticus equivalent

• This baby has persistent seizures after first-line LEV - you should be monitoring seizure burden on continuous EEG, not just observing clinically
• ECD means clinical improvement does not equal electrographic improvement

---

Q8. Describe how you would interpret an amplitude-integrated EEG (aEEG) in this baby.

IDEAL CONSULTANT ANSWER

• Normally present from ~36 weeks CGA onwards
• Visible as regular sinusoidal oscillations in the aEEG band
• Absence of sleep-wake cycling = brain injury marker

• Seizures appear as abrupt rises in the lower margin (acute band-narrowing or sawtooth pattern)
• Large seizures: sudden rise from baseline with return = classic "V" or inverted U shape on compressed trace
• Subtle or brief seizures may be missed on aEEG - false negative rate for aEEG vs full EEG is significant
• Sensitivity of aEEG for seizure detection: ~76-85%; specificity ~90%
• aEEG cannot replace full cEEG - it is a screening/monitoring tool

• Expected finding: focal abnormality - the aEEG may show unilateral background suppression over the affected hemisphere (if 4-channel used)
• Seizure spikes will appear as band-narrowing episodes
• 2-channel aEEG will miss focal hemispheric seizures if the electrodes are over the normal hemisphere

---

Q9. What are the indications for continuous EEG monitoring in neonates? What does the ACNS 2025 guideline say?

IDEAL CONSULTANT ANSWER

1. Any neonate with clinical seizures or suspected seizures
2. Any neonate after a first ASM dose (to detect ECD)
3. HIE being treated with therapeutic hypothermia
4. Perinatal arterial ischemic stroke - your case
5. Intracranial hemorrhage (IVH grade III-IV, SDH, SAH)
6. Neonatal encephalopathy of unknown cause
7. Post-cardiac surgery neonates
8. Neonates with genetic epilepsy or structural brain malformation

• NAIS has a high rate of electrographic-only seizures (up to 70% of ictal events may be subclinical)
• After levetiracetam loading, ECD is expected
• After lacosamide loading, you need to verify electrographic seizure cessation
• You cannot titrate therapy to clinical behavior alone

---

---

SECTION 3: NEONATAL ARTERIAL ISCHEMIC STROKE (NAIS)

---

Q10. Define neonatal arterial ischemic stroke. What is its incidence?

IDEAL CONSULTANT ANSWER

• Fetal stroke - diagnosed in utero
• Neonatal stroke - diagnosed in the first 28 days
• Presumed Perinatal Stroke (PPS) - diagnosed later in infancy/childhood but attributed to perinatal timing (International Pediatric Stroke Study definition)

• 1 in 2,300 to 1 in 5,000 live births (most cited figure: ~1/2,500 to 1/4,000)
• Makes it more common than adult stroke per population age-year
• Second most common cause of neonatal seizures after HIE in term neonates
• MCA territory is involved in >80% of cases
• Left MCA is affected more frequently than right (some series 60-70% left-sided) - reasons discussed below

• It is the most common cause of unilateral (hemiplegic) cerebral palsy diagnosed in infancy
• Often clinically silent at birth (no acute neurological presentation) and presents only with seizures in the first 3 days

---

Q11. What is the pathophysiology of NAIS? Why is the MCA most commonly involved?

IDEAL CONSULTANT ANSWER

• Failure of Na-K-ATPase (energy failure) → ionic shifts: Na⁺/Ca²⁺ into cell, K⁺ out
• Glutamate excitotoxicity - excess glutamate release activates NMDA and AMPA receptors, amplifying Ca²⁺ influx
• Calcium-mediated cell death - activation of calpains, phospholipases, endonucleases
• Peri-infarct depolarizations - spreading cortical depression waves at the penumbra → extend injury zone
• Nitric oxide toxicity - iNOS activation → free radical generation
• Reperfusion injury - if blood flow restores, reactive oxygen species burst worsens cell death (paradoxically)

• The core of infarction is electrically silent (dead neurons cannot fire)
• The penumbra (ischemic but not yet dead) has hyperexcitable neurons due to:
  • Glutamate accumulation
  • Ionic dysregulation (K⁺ efflux → depolarization threshold lowered)
  • Loss of inhibitory interneurons (GABAergic neurons are more ischemia-sensitive)
  • NKCC1/KCC2 immaturity already making GABA excitatory
• Result: focal cortical seizure discharge from the penumbra bordering the infarct

1. Anatomy - The MCA is the direct continuation of the internal carotid artery (ICA). It receives the highest proportion of cerebral blood flow (~70-80%). Any embolus traveling through the ICA most likely enters the MCA.
2. Embolic path of least resistance - Emboli from the heart, aorta, or ductus arteriosus travel via the ICA directly into the MCA. The acute angle of the ACA makes it less likely to receive emboli.
3. Patent ductus arteriosus and paradoxical embolism - In neonates, the PDA and PFO allow right-to-left shunting; emboli from placenta or venous system can bypass the pulmonary circulation and reach the cerebral circulation via the ICA-MCA axis.
4. Caliber of vessel - The MCA's caliber and flow volume make it the dominant embolic target in cerebral circulation.
5. Why left MCA more than right - Proposed mechanisms:
   • The left common carotid artery arises directly from the aortic arch (more direct embolic path)
   • Head position during delivery - left occiput anterior position places the left ICA in a more favorable embolic trajectory
   • Possible fetal circulatory asymmetry - though debated

---

Q12. What is the difference between right MCA and left MCA infarction in terms of clinical presentation and prognosis?

IDEAL CONSULTANT ANSWER

• Left MCA (more common): greater risk of language delay and communication disorders due to Broca's area (inferior frontal) and Wernicke's area (posterior temporal) involvement
• Right MCA: relatively spared language but more visuo-spatial and executive function deficits
• Overall: Neither side is "better" - both carry significant neurodevelopmental burden

• Upper division (anterior, rolandic) → motor cortex, face/arm/hand area
• Lower division (posterior, temporal) → language areas (left), auditory, Wernicke's
• Deep perforators (lenticulostriate arteries) → basal ganglia, internal capsule → more severe motor deficit with smaller infarct volume

---

Q13. Distinguish between cortical infarction, deep nuclear infarction, and watershed infarction in NAIS.

IDEAL CONSULTANT ANSWER

• Involves the cortex and underlying white matter in the territory of a named vessel (MCA, ACA, PCA)
• Mechanism: embolic or in-situ thrombosis of the main arterial trunk or major branch
• MRI: wedge-shaped area of DWI restriction, cortex + subcortical white matter
• Seizure presentation: prominent, focal clonic - because cortical irritation is maximal
• Example: Right MCA infarct in your case - upper division → right precentral gyrus → left UL seizures

• Involves basal ganglia, internal capsule, thalamus (territories of lenticulostriate and thalamo-perforating arteries)
• More associated with thrombotic mechanism or cardiac emboli impacting proximal MCA M1
• MRI: small, round/oval DWI-bright lesion in basal ganglia or internal capsule
• Seizures: less prominent (subcortical)
• Motor outcome often worse - internal capsule involvement → dense hemiplegia even with small lesion

• Involves the boundary zones between major arterial territories:
  • Anterior watershed: between ACA and MCA (parasagittal frontal-parietal)
  • Posterior watershed: between MCA and PCA (temporo-parieto-occipital junction)
• Mechanism: systemic hypoperfusion (cardiac failure, severe hypotension, shock) or bilateral carotid hypoperfusion - NOT embolic
• In HIE: the dominant injury pattern
• In NAIS: unusual - presence of watershed injury should make you suspect systemic hemodynamic compromise, cardiac dysfunction, or twin-twin transfusion
• MRI: linear/chain-like DWI lesions along the watershed zones

---

Q14. At what gestational age / postnatal timing does NAIS typically occur? How do you time the injury from MRI?

IDEAL CONSULTANT ANSWER

• Most neonatal MCA strokes are believed to occur in the perinatal period: typically in the last hours of labor, during delivery, or in the first 24-72 hours of postnatal life
• The window of clinical presentation is Day 1-3 of life (seizures)
• However, the exact timing is often uncertain - this is the fundamental challenge

• Between Days 5-10, the ADC value falsely returns to near-normal despite ongoing infarction
• This is because the initial cytotoxic edema (restricted diffusion) transitions to vasogenic edema (increased diffusion) - the two effects cancel out
• A lesion may appear "missed" on DWI/ADC during this window
• T2 and FLAIR remain bright throughout - use these to avoid missing pseudonormalized infarcts

• DWI bright + ADC dark in the neonatal period → injury within the last 1-7 days
• If MRI is done on Day 2 and shows DWI restriction → strongly supports perinatal or early postnatal injury
• A T1-bright rim (cortical laminar necrosis) at 2 weeks confirms subacute/chronic injury earlier than 7 days

---

---

SECTION 4: ETIOLOGY

---

Q15. Systematically walk me through the etiology of NAIS. What are the maternal, placental, cardiac, thrombotic, and neonatal causes?

IDEAL CONSULTANT ANSWER

MATERNAL CAUSES:

PLACENTAL CAUSES (most important, often underdiagnosed):

CARDIAC CAUSES:

NEONATAL/HEMATOLOGICAL CAUSES:

BIRTH-RELATED / TRAUMATIC CAUSES:

---

---

SECTION 5: IMAGING

---

Q16. Walk me through the MRI sequences in NAIS. What does each sequence show, and what is the optimal timing for MRI?

IDEAL CONSULTANT ANSWER

DWI (Diffusion Weighted Imaging):

• Principle: DWI detects the Brownian motion of water molecules. In cytotoxic edema (cell swelling, restricted intracellular water movement), diffusion is restricted → DWI appears bright.
• In acute infarction (0-7 days): DWI is bright (hyperintense)
• Most sensitive sequence for acute infarction in the first 24-72 hours - it becomes positive within minutes of ischemia
• Why it becomes positive first: CT cannot detect early cytotoxic edema. T2 changes take 6-24 hours. DWI detects the immediate cytotoxic swelling.
• Limitation: DWI shows T2 shine-through in areas of T2 prolongation - must always interpret alongside ADC map

ADC (Apparent Diffusion Coefficient) Map:

• ADC is the quantitative measure of diffusion. It is the complement of DWI.
• In acute infarction: ADC is low (dark) - water diffusion is restricted
• Confirms true restriction (vs T2 shine-through which appears bright on DWI but normal on ADC)
• ADC pseudonormalization (critical concept): Between Days 5-10, ADC returns to near-normal values despite ongoing infarction. This is because cytotoxic edema (↓ADC) transitions to vasogenic edema (↑ADC). They cancel out. A falsely normal ADC at Day 7-10 does NOT mean the infarct has resolved.
• After Day 10-14: ADC becomes elevated (bright) as tissue liquefies → encephalomalacia/cystic change

T1-weighted:

• Acute infarction (0-48 hours): Normal or subtly hypointense
• Subacute (5-14 days): Cortical T1 hyperintensity (cortical laminar necrosis) - hallmark of subacute infarction; due to denatured proteins and lipid-laden macrophages
• Chronic: T1 dark (cystic encephalomalacia)
• Useful for: hemorrhagic transformation (T1 bright blood products), cortical laminar necrosis

T2-weighted:

• Acute (0-6 hours): Normal
• 6-24 hours: Subtle T2 hyperintensity begins
• Days 1-7: Bright T2 in infarct zone - reflects edema
• Chronic: Very bright - cystic encephalomalacia
• In neonates: T2 interpretation is complex because the unmyelinated neonatal brain is normally T2 bright (white matter myelination is incomplete). This means T2 changes can be subtle.

FLAIR (Fluid Attenuated Inversion Recovery):

• Suppresses CSF signal (which is bright on T2) - allows better visualization of cortical and periventricular lesions
• Critical limitation in neonates under 12-18 months: FLAIR is unreliable in neonates because the high water content of unmyelinated neonatal brain suppresses signal similarly to CSF. FLAIR is essentially non-diagnostic in neonates under 3-6 months for infarct detection.
• Do not rely on FLAIR for acute NAIS diagnosis - use DWI/ADC

SWI (Susceptibility Weighted Imaging):

• Detects blood products, hemosiderin, mineralization (iron, calcium, deoxyHb)
• Most sensitive sequence for microhemorrhage, hemorrhagic transformation, cerebral venous thrombosis (deoxyhemoglobin in thrombus appears dark/blooming)
• In NAIS: look for hemorrhagic transformation of the infarct (petechial or confluent)
• In CSVT: SSS or transverse sinus thrombus appears as a dark blooming artifact
• Also detects cortical venous thrombosis invisible on other sequences

MR Angiography (MRA):

• Time-of-flight MRA (no contrast needed): Visualizes Circle of Willis, MCA, ACA, PCA, basilar
• In NAIS: may show absent or reduced flow in the affected MCA segment, or a visible filling defect (thrombus)
• Sensitivity is moderate - small distal branch occlusions may be missed
• Normal MRA does NOT exclude NAIS - the embolus may have already lysed

MR Venography (MRV):

• Essential to exclude CSVT as a cause or contributor
• Shows the dural venous sinuses (SSS, straight sinus, transverse/sigmoid sinuses, vein of Galen)
• In CSVT: absent flow signal or filling defect in affected sinus
• Always perform MRV alongside MRA in neonatal stroke workup

Why CT is often normal in acute NAIS:

• CT detects cytotoxic edema by density changes (hypodense area)
• In the first 6-12 hours, edema is insufficient to produce CT density change
• Neonatal brain is normally hypodense (unmyelinated) - subtle early infarction is invisible
• CT is insensitive for acute neonatal stroke; the only reliable CT finding is loss of gray-white differentiation which takes hours to develop
• CT is NOT the investigation of choice in neonatal seizures - MRI with DWI is mandatory

• Acute MRI (within 24-72 hours): Best for DWI confirmation of acute infarction
• Repeat MRI at Day 7-14: Captures cortical laminar necrosis on T1, clarifies extent; avoids ADC pseudonormalization window if first MRI was at Day 5-7
• MRI at 3 months: Assessment of encephalomalacia, corticospinal tract wallerian degeneration, and hemisphere volume

---

---

SECTION 6: STROKE WORKUP

---

Q17. List every investigation you would order for this baby and justify each. Distinguish evidence-based from non-routine.

IDEAL CONSULTANT ANSWER

TIER 1 - MANDATORY (Evidence-based, universally recommended):

TIER 2 - RECOMMENDED (Supported, select cases or all NAIS):

TIER 3 - SELECTIVE / NOT ROUTINELY RECOMMENDED:

AHA/AAP Guidance:

• Echo in ALL neonates with NAIS
• Thrombophilia testing in neonates with NAIS - including Protein C, S, antithrombin, factor V Leiden, prothrombin mutation, APS antibodies
• Placental pathology in all NAIS
• Testing BOTH parents for thrombophilia if neonatal result is abnormal
• MTHFR alone is NOT an independent risk factor and not routinely tested unless homocysteine is elevated

---

---

SECTION 7: MANAGEMENT

---

Q18. Walk me through the acute management of this baby. Cover stabilization, neuroprotection, and supportive care.

IDEAL CONSULTANT ANSWER

A - AIRWAY & BREATHING:

• Most term neonates with NAIS have intact airway and breathing - they present with seizures, not encephalopathy
• Avoid hypoxia (SpO2 <94%) and hyperoxia (SpO2 >99%) - target SpO2 94-99%
• Hyperoxia is harmful in ischemic brain injury - free radical generation; target normoxia
• Seizures causing apnea may require brief respiratory support - intubation if prolonged apnea

B - GLUCOSE (critical):

• Target blood glucose 2.6-5.5 mmol/L (47-99 mg/dL)
• Hypoglycemia (<2.6) dramatically worsens neurological injury - brain glucose starvation
• Hyperglycemia (>8-10 mmol/L) is also harmful - worsens ischemic neuronal injury through anaerobic metabolism, lactate production, osmotic effects
• Check glucose hourly until stable; IV dextrose infusion if needed

C - SODIUM:

• Avoid hyponatremia (<135 mmol/L) - lowers seizure threshold, causes cerebral edema
• Avoid hypernatremia (>145) - increases serum osmolarity, potentially thrombogenic
• Target Na 135-145 mmol/L; restrict free water if serum Na is falling

D - CALCIUM:

• Hypocalcemia is a treatable cause of neonatal seizures
• Check ionized calcium; replace if needed
• IV calcium gluconate (100-200 mg/kg IV over 10-20 min) for symptomatic hypocalcemia

E - BLOOD PRESSURE:

• This is nuanced and important - avoid extremes
• Hypotension worsens penumbral ischemia - ensure adequate perfusion pressure
• Hypertension (permissive hypertension in adult stroke) is controversial in neonates - BP targets: maintain mean arterial pressure ≥ gestational age in mmHg; avoid aggressive antihypertensive treatment unless severe
• Do NOT use vasopressors aggressively without echo guidance - CHD must be excluded first
• Avoid sudden drops in BP - may extend infarct

F - TEMPERATURE:

• Avoid hyperthermia (>37.5°C) - fever worsens ischemic injury by increasing metabolic demand, glutamate release, and free radical generation
• Therapeutic hypothermia (TH) is NOT indicated in isolated NAIS without co-existing HIE
• If there is concurrent HIE criteria, then TH applies to the HIE, not specifically to the stroke
• Active normothermia (36.5-37.2°C) is the target

G - FLUIDS:

• Maintain euvolemia - avoid dehydration (polycythemia/hyperviscosity worsens thrombosis) and overhydration (cerebral edema)
• Fluid restriction to 60-80 mL/kg/day initially if cerebral edema suspected, titrated to clinical status
• Avoid hypotonic fluids which lower serum sodium

H - NUTRITION:

• Early enteral nutrition once hemodynamically stable
• Maintain normoglycemia
• Consider parenteral nutrition if enteral feeds contraindicated

I - ICP MONITORING:

• Bedside anterior fontanelle assessment clinically
• Formal ICP monitoring (invasive) is not routine in NAIS
• Signs of raised ICP: full/bulging fontanelle, bradycardia + hypertension (Cushing triad), worsening level of consciousness, pupillary changes
• If large hemispheric infarction with massive edema (rare in neonates): consider neurosurgical consultation, osmotic therapy (hypertonic saline preferred over mannitol in neonates)
• Decompressive hemicraniectomy is not established in neonates

J - SEIZURE CONTROL (covered in Section 8)

K - ANTICOAGULATION (covered in Section 9)

---

---

SECTION 8: ANTISEIZURE MEDICATIONS

---

Q19. Discuss phenobarbitone as first-line treatment in neonatal seizures - mechanism, dose, pharmacokinetics, adverse effects, and evidence.

IDEAL CONSULTANT ANSWER

Mechanism:

• Primary mechanism: Enhances GABA-A receptor function → increases Cl⁻ conductance → hyperpolarization
• Paradox in neonates: Because NKCC1 > KCC2 in neonates (high intracellular Cl⁻), GABA-A activation may actually depolarize neonatal neurons rather than hyperpolarize them → this is why phenobarbitone is less effective in neonates than in older children, and explains why it achieves only ~55% electrographic seizure cessation
• Additional mechanisms: blocks AMPA/kainate glutamate receptors at high doses, reduces neuronal firing

Pharmacokinetics in Neonates:

• Loading dose: 20 mg/kg IV (first-line)
• If seizures persist: additional doses of 10 mg/kg IV up to a maximum of 40 mg/kg total
• Maintenance dose: 3-5 mg/kg/day in once-daily or BD dosing (long half-life)
• Half-life in neonates: Very long - 40-200 hours (vs 50-160 hours in adults; neonatal hepatic metabolism immature)
• Volume of distribution: 0.8-1 L/kg (higher than adults)
• Protein binding: Low in neonates (albumin capacity less)
• Elimination: Hepatic (CYP2C19, CYP2C9) + renal; autoinduction of metabolism occurs
• Therapeutic level: 15-40 mg/L (some use 20-40 mg/L for seizure control)

Adverse Effects:

• Respiratory depression - most important acute risk; have bag-mask ventilation ready
• Hypotension - vasodilation; avoid in hemodynamically compromised babies
• Sedation - reduces interaction, makes neurological assessment difficult
• Neurotoxicity (long-term, animal data): Phenobarbitone induces apoptotic neurodegeneration in the developing brain (Bittigau et al., 2002, PNAS) - this is the principal concern about long-term use; human data are less clear but concerning
• Interaction with HIE: In babies receiving TH, metabolism is further slowed → drug accumulates → higher sedation risk

Evidence:

• Painter et al., NEJM 1999: RCT comparing phenobarbitone vs phenytoin as first-line - both achieved clinical seizure control in ~43-45% but electrographic control only in ~55%
• Sharpe et al., JAMA Pediatr 2016 (PhenoB study): Phenobarbitone superior to phenytoin in HIE
• ILAE 2023 Guideline (Pressler et al.): Phenobarbitone remains recommended first-line (moderate evidence) - despite its limitations; no other drug has been shown superior in adequately powered RCTs
• NeoLEV2 (Sharpe et al., 2020, NEJM): Randomized trial of LEV vs PB in HIE-associated seizures - PB was superior to LEV as first-line (seizure cessation 80% vs 28% for PB)

---

Q20. Discuss levetiracetam - why was it chosen initially, why did it fail, what is the evidence?

IDEAL CONSULTANT ANSWER

Mechanism:

• Binds synaptic vesicle glycoprotein SV2A - modulates presynaptic neurotransmitter release
• Does NOT act on GABA or glutamate receptors directly
• Also inhibits N-type Ca²⁺ channels, reduces hypersynchronous firing
• Key advantage conceptually: Because it does NOT rely on GABA (which is excitatory in neonates), it theoretically avoids the NKCC1/KCC2 paradox

Pharmacokinetics in Neonates:

• Loading dose: 20-60 mg/kg IV (varied across centers; most use 20-40 mg/kg)
• Maintenance: 10-30 mg/kg/day in BD dosing
• Half-life in neonates: 10-20 hours (compared to 6-8 hours in adults) - immature renal clearance
• Elimination: 60-70% renal (unchanged); dose reduce in renal impairment
• Protein binding: <10% - minimal drug interactions
• Advantages over phenobarbitone: Less sedation, no respiratory depression, no autoinduction, less apoptosis in animal models

Why Levetiracetam May Fail in Neonates:

1. SV2A receptor is developmentally regulated - expression is lower in the immature neonatal brain, especially in preterm and early-term neonates. The drug has less binding target.
2. Pharmacokinetic underdosing - Studies suggest doses of 20 mg/kg are insufficient; some centers use 40-60 mg/kg loading doses
3. Mechanism mismatch - In acute ischemic seizures, the dominant mechanism is glutamate-NMDA mediated excitotoxicity and ionic shifts, not primarily synaptic vesicle trafficking. LEV's mechanism may be less relevant to the acute seizure mechanism.
4. Evidence simply shows inferiority to phenobarbitone:
   • NEOLEV (Sharpe et al., 2015, Epilepsia): Pilot RCT - LEV vs PB; suggested LEV may be comparable but underpowered
   • NeoLEV2 (Sharpe et al., 2020, NEJM): Definitive RCT, n=106; PB superior: 80% vs 28% seizure cessation (p<0.001). LEV was clearly inferior to PB as first-line.
   • Meta-analyses (Kumar et al., Indian J Pediatr 2025; Salim et al., 2025) confirm PB superior to LEV

Why Your Case Received LEV First:

• Many NICUs still use LEV first due to its superior safety profile (less sedation, less respiratory depression, less apoptosis)
• The ILAE 2023 guidelines acknowledge PB is evidence-based first-line, but recognize that some centers use LEV first based on safety profile - this is a consensus deviation
• In NAIS specifically, the baby is not encephalopathic - so concerns about PB sedation masking neurological assessment are valid
• LEV failure (as in your case) mandates escalation per protocol

---

Q21. Discuss lacosamide in neonates - mechanism, evidence, dose, ECG monitoring requirements, and safety.

IDEAL CONSULTANT ANSWER

Mechanism:

• Dual mechanism:
  1. Selective enhancement of slow inactivation of voltage-gated sodium channels (Nav) - unlike phenytoin/carbamazepine which enhance fast inactivation, lacosamide specifically enhances slow inactivation - this is a unique mechanism that complements other Na-channel blockers
  2. Binds CRMP-2 (collapsin response mediator protein 2) - role in neuronal differentiation and axonal outgrowth; exact relevance to seizure suppression is debated
• Why it may work when other agents fail: Its slow Na-channel inactivation mechanism is complementary to both PB (GABA mechanism) and LEV (SV2A mechanism) - different molecular target = additive effect

Neonatal Pharmacokinetics:

• Loading dose in neonates: 8-10 mg/kg IV (some protocols: 5-10 mg/kg; max 15 mg/kg per some case series)
• Maintenance: 5-8 mg/kg/day in BD dosing
• Half-life in neonates: Estimated 14-20 hours (limited data; adults ~13 hours)
• Elimination: Primarily renal (40% unchanged); hepatic CYP2C19 (30%)
• Protein binding: <15%
• Available formulations: IV and oral - important as can transition to oral maintenance

Evidence in Neonates:

• No RCT exists for lacosamide in neonates - all evidence is retrospective observational
• Bamgbose et al., J Child Neurol 2023: Safety and tolerability study in neonates - generally well tolerated; no serious adverse events attributable to lacosamide
• Chourasia et al., Pediatr Neurol 2024: Retrospective single-center - adjunct use after PB/LEV failure; 60% reduction in seizure burden
• Kaur et al., Pediatr Neurol 2024 (multicenter): EEG response to lacosamide in neonates - electrographic response seen in ~50-60% of refractory cases; cardiac monitoring important
• Langton et al., Epilepsia 2022: Animal model showing lacosamide reduces neonatal seizures without increasing apoptosis (unlike phenobarbitone) - important safety signal
• Gettings & Soul, Clin Perinatol 2025: Review endorsing lacosamide as a viable option in refractory neonatal seizures

CRITICAL - ECG Monitoring:

• PR interval prolongation is the most important adverse effect of lacosamide
• Mechanism: Nav slow inactivation in cardiac conduction tissue (SA node, AV node)
• In adults, PR prolongation >200 ms (first-degree AV block) requires dose reduction; second/third-degree AV block is a contraindication
• In neonates: ECG should be performed before and after lacosamide loading
• Target: PR interval <100 ms in neonates (normal neonatal PR = 70-130 ms depending on heart rate)
• Contraindicated if: Pre-existing AV block, known channelopathy (Brugada syndrome - though extremely rare in neonates), significant cardiac structural disease affecting conduction
• Drug interactions: Avoid combining with other sodium-channel drugs (phenytoin, carbamazepine) - additive cardiac conduction effects

Maximum dose: Most neonatal case series use up to 15-20 mg/kg total loading dose

---

Q22. Discuss phenytoin, midazolam, lidocaine, and bumetanide in neonatal seizures.

IDEAL CONSULTANT ANSWER

PHENYTOIN / FOSPHENYTOIN:

• Mechanism: Fast Na-channel inactivation (different from lacosamide's slow inactivation)
• Loading dose: 20 mg/kg IV (phenytoin; must be given in saline, not dextrose - precipitates)
• Fosphenytoin (prodrug): 20 mg PE/kg; can be given in dextrose/saline, less cardiac risk
• Adverse effects: Severe cardiac arrhythmias during rapid IV infusion (bradycardia, heart block), hypotension, venous irritation (phenytoin pH 12)
• Neonatal PK: Saturable kinetics (Michaelis-Menten) even in adults; in neonates highly variable. Half-life 40-140 hours (varies enormously). Therapeutic level 15-20 mg/L.
• Evidence: Painter et al., NEJM 1999: equivalent to PB as first-line (clinical seizure cessation ~45%); BUT electrographic cessation similar
• Current role: Third-line after PB + LEV failure; being displaced by lacosamide

MIDAZOLAM:

• Mechanism: GABA-A positive allosteric modulator (benzodiazepine binding site)
• Loading dose: 0.05-0.15 mg/kg IV bolus
• Infusion: 0.01-0.1 mg/kg/hour (continuous infusion for status epilepticus)
• Advantages: Fast onset, easily titratable
• Problems in neonates:
  1. GABA may be excitatory in neonates (NKCC1 dominance) - paradoxical seizure exacerbation possible
  2. Acute tolerance develops rapidly with continuous infusion
  3. Respiratory depression
  4. Accumulation (active metabolites: α-hydroxymidazolam)
• Evidence: Case series show ~70% response rate in refractory seizures; Shany et al. and other studies support its use
• ILAE 2023: Second or third-line option after phenobarbitone

LIDOCAINE (Lignocaine):

• Mechanism: Na-channel blockade (class 1b antiarrhythmic)
• Neonatal use: Intravenous infusion 2-7 mg/kg/hour (Dutch/Scandinavian protocols)
• Evidence: Several European studies (Malingré, de Vries et al.) show efficacy in PB-refractory seizures
• Critical safety issue: NEVER combine with phenytoin or other Na-channel blockers - additive cardiac toxicity (ventricular arrhythmias, VT)
• ECG monitoring mandatory
• Not used in many centers outside Europe due to narrow therapeutic index and cardiac risk

BUMETANIDE (Research/experimental):

• Rationale (theoretically compelling): Bumetanide is a NKCC1 inhibitor (loop diuretic). By blocking NKCC1, it reduces intracellular Cl⁻ in neonatal neurons, allowing GABA to be inhibitory rather than excitatory. In theory, this should dramatically reduce neonatal seizures and even restore phenobarbitone efficacy.
• Animal data: Very promising - dramatically reduces neonatal seizures in rodent models
• Human clinical trials:
  • NEMO Trial (Pressler et al., 2015, Lancet Neurol): Multicentre RCT of bumetanide in neonates with HIE-associated seizures. Result: Bumetanide was NOT effective in reducing seizure burden vs placebo. High rates of adverse events - particularly hearing loss (ototoxicity - bumetanide targets NKCC1 in the cochlea as well). Trial stopped early.
• Current status: NOT recommended clinically due to lack of efficacy and ototoxicity. Remains a research compound.
• Lesson: Mechanistically attractive drugs can fail clinically - NEMO trial is a cautionary tale

---

---

SECTION 9: ANTITHROMBOTIC THERAPY

---

Q23. What is the role of anticoagulation and antiplatelet therapy in NAIS? What do current guidelines recommend?

IDEAL CONSULTANT ANSWER

ASPIRIN:

• Why not routinely used in NAIS:
  1. No RCT evidence in neonates
  2. Aspirin is an antiplatelet agent - most NAIS is embolic (thromboembolic), not platelet-mediated
  3. Risk of Reye syndrome if given during viral illness (low risk in neonates but theoretically present)
  4. Hemorrhagic transformation risk in acute infarct
  5. The stroke has already occurred - aspirin for primary prevention of further stroke is the rationale, not treatment of the acute event
• When aspirin IS indicated in NAIS:
  • Congenital heart disease with known embolic risk (intracardiac thrombus, post-cardiac surgery, palliative procedure)
  • Moyamoya disease (unusual in neonates)
  • Presumed Perinatal Stroke presenting later in infancy (not acute neonatal period)
  • Dose: 1-5 mg/kg/day orally

LMWH (Low Molecular Weight Heparin - Enoxaparin):

• When LMWH is indicated in NAIS:
  1. Documented cardioembolic source (intracardiac thrombus, mechanical heart valve, cardiomyopathy with low EF)
  2. Cerebral Sinovenous Thrombosis (CSVT) - this is the strongest indication; AHA recommends therapeutic anticoagulation for CSVT even in neonates with hemorrhagic infarction
  3. Documented major thrombophilia with ongoing prothrombotic risk (homozygous Protein C deficiency, antithrombin deficiency)
  4. Catheter-associated thrombosis causing neurological events
• Why LMWH is generally NOT given routinely for uncomplicated NAIS:
  • No RCT evidence of benefit
  • Risk of hemorrhagic transformation (up to 20-30% of NAIS already has some hemorrhagic transformation on SWI)
  • The acute stroke has already occurred - the clot is no longer in the artery; it has either lysed or caused infarction
  • AHA 2019 Pediatric Stroke Guidelines: "Anticoagulation or aspirin therapy may be considered in neonates with NAIS when a cardioembolic source or symptomatic cervical arterial dissection is identified" (Class IIb, Level C)
• LMWH dose (Enoxaparin):
  • Treatment dose (therapeutic): 1.5 mg/kg/dose SC BD (neonates require higher weight-adjusted doses than adults due to different volume of distribution and anti-Xa clearance)
  • Prophylactic dose: 0.75 mg/kg/dose SC BD
  • Monitor: Anti-Xa levels (target therapeutic: 0.5-1.0 IU/mL; 4 hours post-dose)

WHEN ANTICOAGULATION IS CONTRAINDICATED:

• Active intracranial hemorrhage (other than small petechial transformation)
• Large hemorrhagic infarction
• Thrombocytopenia (<50,000) - relative contraindication
• Active DIC
• Hypertension not yet controlled

Summary of AHA/AAP Position:

• Routine anticoagulation NOT recommended for uncomplicated NAIS
• Anticoagulation IS recommended for CSVT
• Aspirin or LMWH may be considered for NAIS with documented cardioembolic source
• Thrombolytic therapy (tPA) is NOT recommended in neonates - no safety or efficacy data, and the neonatal hemostatic system is already at hemorrhagic risk

---

---

SECTION 10: PROGNOSIS

---

Q24. What is the prognosis for this baby? Cover epilepsy risk, cerebral palsy, cognitive and behavioral outcomes.

IDEAL CONSULTANT ANSWER

EPILEPSY / SEIZURE RECURRENCE:

• Acute seizure control: Most neonatal post-stroke seizures resolve within Days 3-7 of life
• Risk of epilepsy (post-neonatal, recurrent seizures):
  • Approximately 25-46% of neonates with NAIS develop epilepsy
  • Most studies cite ~30-35% risk of post-neonatal epilepsy
  • Risk factors for post-neonatal epilepsy: large infarct volume, cortical involvement (vs pure subcortical), involvement of temporal lobe, MRI at 3 months showing extensive encephalomalacia
  • Seizures may not begin until 6-24 months of age - during active cortical reorganization
  • EEG at 3-6 months should be performed to detect interictal epileptiform discharges (risk marker)

HEMIPLEGIC CEREBRAL PALSY:

• NAIS is the most common cause of hemiplegic CP
• Risk of hemiplegia: ~50-75% of term neonates with unilateral MCA infarction
• Laterality: CP affects the contralateral side to the infarct (right MCA → left hemiplegia in your case)
• Severity predictors:
  • Internal capsule involvement → high risk of dense hemiplegia
  • Corticospinal tract (CST) Wallerian degeneration on MRI at 3 months → high risk
  • DTI (diffusion tensor imaging) at 3 months is most predictive - asymmetry of CST predicts motor outcome
  • Posterior limb of internal capsule (PLIC) signal loss on T1 at 2 weeks → worse motor prognosis

LANGUAGE:

• Left MCA infarction (more common) → risk of expressive and/or receptive language delay in 30-50%
• Right hemisphere plasticity allows remarkable language recovery in infants (Broca's area is bilateral in early life) - better language outcomes than in adult left MCA stroke
• Speech therapy referral by 6 months

COGNITIVE:

• Variable; intelligence within normal range in ~50-60%
• Executive function deficits common even with normal IQ
• Working memory, processing speed affected

BEHAVIORAL OUTCOMES:

• ADHD: Elevated risk (~30%) compared to general population
• Autism Spectrum Disorder: Slightly elevated risk, especially with right hemisphere involvement and extensive white matter injury
• Anxiety and behavioral regulation difficulties common
• These behavioral outcomes are often more disabling than motor outcomes and are underrecognized

REPEAT IMAGING:

• MRI at 3 months: Assess encephalomalacia extent, CST Wallerian degeneration (T2/DTI), hemisphere volume, myelination progress
• MRI at 1-2 years: If clinical concerns persist
• DTI tractography (if available) at 3-6 months: most precise tool for motor outcome prediction

---

---

SECTION 11: PARENT COUNSELLING

---

Q25. Simulate parent counselling for these common questions.

---

"We cannot give you a definite answer today because your baby's brain is still developing. What we know is this: the stroke has affected a part of the brain that controls movement on one side of the body. Many babies with this condition do walk - in fact, the majority do walk independently, often by 18-24 months, though one side of the body may be weaker or move differently. We will start physiotherapy early, and modern neurological rehabilitation is very effective in the first years of life because the baby's brain is highly adaptable - it can reroute pathways to compensate. We will monitor your baby closely with brain scans and developmental reviews, and I will be more specific about walking prospects once we see how the brain has recovered on the 3-month MRI."

"The seizures your baby is having now are related to the acute injury - they usually settle within the first week. However, there is a real risk - about 1 in 3 babies with this type of stroke may develop epilepsy later, usually in the first 1-2 years of life. This is not certain, and we will monitor your baby with EEG tests over time. If seizures return, they are usually treatable. We will give you guidance on what to watch for at home and make sure you have a clear action plan."

"The antiseizure medicines we are using now are for the acute period. Our current guidance is to try to stop them before discharge if seizures are controlled and EEG is normal, because the developing brain recovers and often does not need long-term medication. However, if epilepsy develops later, long-term medication may be needed - we will reassess at each follow-up. Most babies with stroke-related epilepsy respond well to one medication."

"A recurrent neonatal stroke in the same baby is uncommon if we identify and treat the underlying cause. We are doing thorough investigations - including heart scans, blood clotting tests, and examination of the placenta - to find out why this happened. If we find a significant clotting disorder or heart problem, we will treat it and reduce the risk. In most cases, there is no recurrence. However, the risk depends on what we find."

"This is an important question. If we find a hereditary clotting disorder in your baby, we will test you both as parents as well. In some cases, we recommend pre-pregnancy genetic counselling. Most mothers of babies with neonatal stroke go on to have healthy pregnancies - but we want to know the full picture first. Once our investigations are complete, I can give you much more specific guidance. We can arrange a formal pre-pregnancy counselling consultation."

"Your baby can and should receive all routine vaccinations on schedule. Having had a stroke does not mean vaccines need to be delayed or avoided - in fact, infections like pertussis and pneumococcal disease can be more dangerous in babies with neurological conditions. If your baby develops epilepsy, we will discuss the timing of specific vaccines like MMR with your neurologist, but standard neonatal vaccines are safe and recommended."

"Physiotherapy helps the brain and muscles work together as your baby grows. Early physiotherapy - starting in the first few months of life - takes advantage of the brain's plasticity, meaning its ability to reorganize and form new pathways. In babies with weakness on one side, constraint-induced movement therapy (CIMT) - encouraging use of the weaker limb - has been shown to dramatically improve hand function. We will refer you to a pediatric physiotherapist and occupational therapist before discharge."

---

---

SECTION 12: EVIDENCE-BASED MEDICINE

---

Q26. Review the landmark trials and guidelines relevant to this case.

KEY LANDMARK TRIALS:

---

---

SECTION 13: RAPID-FIRE VIVA - 50 ONE-LINE QUESTIONS WITH ANSWERS

---

---

---

FINAL SUMMARY

---

1. IDEAL CONSULTANT ANSWERS (Key Synthesis)

• Problem representation: Synthesize - do not recite. Pivot on lateralized semiology + absent HIE context + refractory ASM requirement.
• MCA involvement: High-flow, direct embolic path from ICA; lenticulostriate perforators supply deep structures; cortical penumbra generates seizures.
• ECD: Phenobarbitone/LEV suppress clinical manifestations more than electrographic discharges; cEEG is mandatory.
• ILAE 2023: PB is still first-line; LEV inferiority confirmed by NeoLEV2; lacosamide is a rational third-line adjunct but has no RCT data.
• Placental histopathology is the highest-yield single investigation.
• Anticoagulation: Not routine for uncomplicated NAIS; reserve for CSVT, documented cardiac source, or major thrombophilia.

---

2. COMMON MISTAKES RESIDENTS MAKE

1. Saying "subtle seizures" without EEG correlation - ILAE 2021 eliminated this term
2. Not ordering cEEG after first ASM dose - missing electrographic status epilepticus
3. Assuming levetiracetam is as good as phenobarbitone - NeoLEV2 clearly refuted this
4. Forgetting placental histopathology - most commonly missed investigation
5. Starting anticoagulation empirically without clear indication - risk of hemorrhagic transformation
6. Not checking ECG before lacosamide - PR prolongation risk
7. Using FLAIR to diagnose neonatal stroke - unreliable before 3-6 months
8. Not distinguishing CSVT from NAIS on imaging - different treatment (LMWH for CSVT)
9. Stopping seizure workup at normal glucose/calcium - missing structural/vascular etiology
10. Continuing ASMs indefinitely post-discharge - ILAE recommends early discontinuation if seizures controlled

---

3. HIGH-YIELD VIVA PEARLS

• GABA is excitatory in neonates (NKCC1 > KCC2) - this explains why PB is less effective AND why bumetanide was rationally designed
• NeoLEV2 (NEJM 2020) - PB 80% vs LEV 28% - know this number cold
• ADC pseudonormalization Days 5-10 - the dangerous imaging window
• Placental FTV - in 10-65% of NAIS; always request histopathology
• Electroclinical dissociation - after PB loading, ~45% of seizures are now electrographic-only
• Left MCA more common than right MCA in NAIS
• CSVT vs NAIS - MRV, non-territorial lesion, hemorrhagic infarction = CSVT
• Lacosamide - ECG - this will always be asked; PR prolongation is the key adverse effect
• NEMO trial - bumetanide failed clinically despite beautiful mechanism
• Prognosis: 30-35% epilepsy risk, 50-75% hemiplegia risk; remarkable plasticity for language

---

4. RECENT GUIDELINE UPDATES (2023-2026)

---

5. TEN "CONSULTANT FAVOURITE" QUESTIONS ALMOST ALWAYS ASKED IN DM/DrNB NEONATOLOGY ROUNDS

---

---

• Sections 1-4 cover clinical synthesis, seizure science, stroke pathophysiology, and etiology - the conceptual foundation questions
• Section 5 is pure neuroradiology - every sequence with its mechanism and limitation
• Section 6 is the workup table with explicit evidence grading (Tier 1/2/3 - mandatory vs selective)
• Sections 7-9 are management - stabilization targets with exact numbers, each ASM with mechanism/dose/evidence/adverse effect, and antithrombotic controversy
• Section 10-11 are prognosis and parent counselling scripts you can use verbatim
• Section 12 contains the landmark trial table - NeoLEV2, NEMO, Painter, ILAE 2023 all with findings
• Section 13 is the 50-question rapid-fire table - print this and drill it before exam
• The final summary has the 10 "consultant favourite" questions - these are the ones that distinguish a registrar from a candidate who passes DM/DrNB rounds

• NeoLEV2: PB 80% vs LEV 28%
• Epilepsy after NAIS: ~30-35%
• Hemiplegia after NAIS: ~50-75%

• "Answer to Q[number]" - if you want me to revisit a specific question from the viva above
• "Continue the viva" - if you want me to ask the next set of questions interactively
• "Explain [topic]" - if you want deeper elaboration on any section (e.g., lacosamide dosing, MRI sequences, NeoLEV2 trial, thrombophilia workup)
• "Quiz me on Section 13" - if you want me to fire rapid-one-liners at you for self-testing
• "New case" - if you want a fresh NICU viva on a different scenario

NEONATAL ARTERIAL ISCHEMIC STROKE

Complete DM Neonatology Teaching Document

Consultant-Level | Evidence-Based | Examination Ready

---

How to use this document: This is written at the level expected of a DM Neonatology fellow preparing for consultant rounds. Every "why" is explained. Read it like a textbook chapter written by your attending, not a review article. Citations are embedded where relevant. Tables, algorithms, mnemonics, and viva questions are integrated throughout.

---

---

SECTION 1: DEFINITION AND CLASSIFICATION

---

1.1 What Is Neonatal Stroke?

"A group of heterogeneous conditions in which there is focal disruption of cerebral blood flow secondary to arterial or venous thrombosis or embolization, occurring between 20 weeks of fetal life through the 28th postnatal day, confirmed by neuroimaging or neuropathologic studies."

---

1.2 Classification of Neonatal Stroke

---

1.3 Why Neonatal Stroke Differs from Childhood Stroke

---

---

SECTION 2: EPIDEMIOLOGY

---

2.1 Incidence

• 1 in 2,300 to 1 in 5,000 live births - the most widely cited range
• Most authoritative figure: ~1 in 2,500 to 1 in 4,000 term neonates
• Incidence of PPIS (presenting later) adds to this: total perinatal stroke burden estimated ~1/2,300
• NAIS is more common than any single pediatric cancer and more common than childhood stroke
• Makes it the second most common cause of neonatal seizures in term babies (after HIE)
• NAIS is the most common identifiable cause of hemiplegic cerebral palsy

2.2 Age at Presentation

• Acute neonatal presentation: Day 1-3 of life (most common)
• Peak: Day 2 - which is exactly your case
• The reason for this timing: the perinatal circulatory transition (closure of PDA/PFO, shift from fetal to neonatal circulation) occurs over the first 24-72 hours, increasing embolic risk
• Delayed presentation (PPIS): 3-6 months of age (when asymmetric hand use becomes apparent)

2.3 Which Babies Are at Highest Risk?

• Term neonates (>37 weeks) - NAIS is predominantly a term baby problem; preterm babies get periventricular leukomalacia and IVH, not territorial MCA infarction
• Male sex (slight predominance, ~60% male)
• Primigravida mothers (higher rates of prolonged labor, instrumental delivery)
• Maternal thrombophilia carriers
• Babies with congenital heart disease
• Babies of mothers with chorioamnionitis or preeclampsia
• IUGR babies (polycythemia, hyperviscosity)
• Babies receiving ECMO (high stroke risk from cannula + anticoagulation fluctuations)
• Post-cardiac surgery neonates

---

---

SECTION 3: PATHOPHYSIOLOGY

---

3.1 Why Does Stroke Occur Around Birth? The Five Converging Mechanisms

Mechanism 1: Fetal Circulation and Transitional Physiology

• PVR drops → pulmonary blood flow increases → LA pressure rises → PFO begins to close
• Clamping of the cord → PDA begins to close
• The transitional period (first 24-72 hours) is hemodynamically unstable

• During the transition, right-to-left shunting persists intermittently → paradoxical embolism is possible: a venous thrombus (from placenta, UAC/UVC, or deep veins) can cross a patent PFO and enter the systemic (cerebral) arterial circulation
• The foramen ovale is a direct conduit from right atrium to left atrium; a clot traveling from the placenta through the umbilical vein → IVC → RA → PFO → LA → aorta → ICA → MCA

Mechanism 2: Relative Neonatal Hypercoagulability

• Fetal hemoglobin has higher O2 affinity → lower O2 delivery → compensatory polycythemia in many neonates
• Hematocrit at term: 45-65% - when Hct >65% (polycythemia), viscosity increases exponentially
• High fibrinogen and activated coagulation cascade during labor
• Relatively low Protein C and S (natural anticoagulants) - physiologically low in neonates (40-60% of adult levels)
• Net result: a prothrombotic milieu at the time of circulatory transition

Mechanism 3: Placental Thromboembolism

• Thrombin is generated at the placental bed
• Fetal thrombotic vasculopathy (FTV) - thrombi in the fetal stem villous vessels - can send emboli upstream through the umbilical vein → cardiac circulation → cerebral arteries
• This is confirmed by placental histopathology in 10-65% of NAIS cases
• The placenta is the "upstream factory" of the embolus

Mechanism 4: Perinatal Inflammation (Chorioamnionitis Pathway)

Mechanism 5: Birth-Related Vascular Injury

• Forceps application → direct pressure on the temporal region → ICA/MCA injury
• Vacuum extraction → scalp traction → neck extension → carotid dissection
• Shoulder dystocia → hyperextension of neck → carotid stretch injury
• These cause in-situ thrombosis or dissection rather than embolism

---

3.2 The Ischemic Cascade: What Happens in the Brain

Arterial occlusion
        ↓
Energy failure (ATP depleted in 2-5 minutes)
        ↓
Na-K-ATPase fails → Na+ / Ca2+ enter cells, K+ exits
        ↓
Cytotoxic edema (cell swelling) → DWI restriction
        ↓
Glutamate release (excitotoxicity) → NMDA receptor activation → Ca2+ flooding
        ↓
Calpain / phospholipase / endonuclease activation → cell death
        ↓
Peri-infarct spreading depolarizations → extend the injury zone
        ↓
iNOS activation → nitric oxide / free radicals → oxidative damage
        ↓
Reperfusion injury (if blood flow restores) → ROS burst

• Core: Dead tissue within minutes - electrically silent
• Penumbra: Ischemic but viable tissue at the border zone - hyperexcitable due to ionic shifts, glutamate accumulation, and loss of GABAergic interneurons (which are more ischemia-sensitive) → the penumbra IS the seizure generator

• NKCC1 > KCC2 → GABA is excitatory (explained in detail in Section 8)
• Excess NMDA receptor density in neonatal cortex
• Immature inhibitory interneurons
• High extracellular glutamate from ischemia activates an already hyperexcitable system

---

---

SECTION 4: RISK FACTORS

---

4.1 Complete Risk Factor Classification

MATERNAL RISK FACTORS:

PLACENTAL RISK FACTORS:

FETAL/NEONATAL RISK FACTORS:

CARDIAC RISK FACTORS:

GENETIC THROMBOPHILIA:

---

---

SECTION 5: CLINICAL PRESENTATION

---

5.1 The Classical Presentation Triad

1. Focal clonic seizures (most common - present in 70-90%)
2. Term baby, Day 1-3 of life
3. No features of HIE (no perinatal asphyxia, Apgar scores normal or near-normal, no acidosis)

---

5.2 Seizure Characteristics

• Focal clonic = cortical irritation (penumbra around infarct in motor cortex) → most specific for NAIS
• Tonic = deeper or bilateral involvement
• Subtle = this term is being retired by ILAE 2021; these may represent non-epileptic behaviors or subcortical seizures

---

5.3 Other Presentations

---

5.4 How to Differentiate NAIS from Common Mimics

---

---

SECTION 6: DIAGNOSTIC APPROACH

---

6.1 Stepwise Algorithm

TERM NEONATE + FOCAL CLONIC SEIZURES (Day 1-3)
                    │
        ┌─────────────────────────┐
        │   IMMEDIATE STABILIZATION  │
        │  • Airway / breathing       │
        │  • SpO2 target 94-99%       │
        │  • Bedside glucose NOW      │
        │  • IV access                │
        │  • Temperature (36.5-37.2°C)│
        └─────────────┬───────────────┘
                      │
              Is glucose low?
           YES → IV dextrose (2mL/kg D10W bolus)
           NO → Continue
                      │
        ┌─────────────────────────┐
        │  FIRST INVESTIGATIONS   │
        │  • Blood glucose        │
        │  • Serum Ca, Na, Mg     │
        │  • CBC + differential   │
        │  • CRP + blood culture  │
        │  • Coagulation (PT,aPTT,│
        │    INR, fibrinogen, D-dimer)│
        └─────────────┬───────────────┘
                      │
        ┌─────────────────────────┐
        │  ANTISEIZURE MEDICATION  │
        │  (if seizure ongoing)    │
        │  → First-line: PB 20mg/kg│
        └─────────────┬────────────┘
                      │
        ┌─────────────────────────┐
        │    EEG / aEEG           │
        │  • Confirm electroclinical│
        │    correlation           │
        │  • Start continuous EEG  │
        └─────────────┬────────────┘
                      │
        ┌─────────────────────────┐
        │   NEUROIMAGING          │
        │  MRI BRAIN (PRIORITY 1) │
        │  DWI + ADC + T1 + T2    │
        │  SWI + MRA + MRV        │
        └─────────────┬────────────┘
                      │
              MRI confirms infarct?
                      │
        YES → NAIS CONFIRMED
                      │
        ┌─────────────────────────┐
        │  EXTENDED WORKUP        │
        │  • Echocardiography     │
        │  • ECG                  │
        │  • Thrombophilia panel  │
        │  • Placental histopath  │
        │  • APS antibodies       │
        │  • Metabolic screen     │
        │    (if atypical)        │
        └─────────────────────────┘

---

6.2 Why Each Investigation Is Ordered

---

---

SECTION 7: NEUROIMAGING

---

7.1 Why MRI Is Mandatory and CT Is Unreliable in NAIS

• In the first 6-12 hours: CT is normal - cannot detect cytotoxic edema
• Neonatal brain is normally hypodense (unmyelinated white matter is water-rich) → subtle early infarction invisible
• Gray-white matter differentiation is poor at baseline in neonates
• CT sensitivity for acute NAIS in first 24 hours: <30%
• CT only becomes positive at 24-48 hours when vasogenic edema produces detectable hypodensity

• Cranial US misses up to 50-60% of NAIS - it cannot reliably detect cortical infarcts, small infarcts, or posterior territory infarcts
• It is useful for IVH and PVL but not for cortical arterial stroke
• A normal cranial US does NOT exclude NAIS

---

7.2 MRI Sequences - Detailed Teaching

DWI (Diffusion Weighted Imaging)

• Becomes positive within minutes of ischemia onset
• Peak brightness at Days 2-5
• Begins to fade after Day 7
• By Day 14: may be isointense or fading

---

ADC Map (Apparent Diffusion Coefficient)

• ADC is a calculated map of the diffusion coefficient
• Low ADC (dark) = restricted diffusion = cytotoxic edema = acute infarct ✓
• High ADC (bright) = free diffusion = normal or chronic (encephalomalacia)

Day 0-5:    ADC LOW (dark) ← cytotoxic edema dominates
Day 5-10:   ADC NORMALIZING ← cytotoxic + vasogenic cancel out
Day 10-14+: ADC HIGH (bright) ← vasogenic edema + liquefaction dominates

---

T1-Weighted Imaging

• The most ischemia-sensitive cortical layers (III, V) undergo necrosis first
• Dead and dying neurons become T1 bright due to denatured proteins and lipid-laden macrophages (which accumulate as phagocytosis begins)
• Appears as a gyral T1 bright ribbon overlying the infarct zone
• Confirms subacute infarction - if seen, the infarct is 1-2 weeks old
• This is useful for timing the injury

---

T2-Weighted Imaging

---

FLAIR (Fluid-Attenuated Inversion Recovery)

• The neonatal brain's unmyelinated white matter has very high water content with long T1 relaxation times - similar to CSF
• The FLAIR inversion pulse designed to null CSF also partially suppresses the neonatal brain signal
• Result: FLAIR is unreliable and insensitive in neonates under 3-6 months (some say up to 12-18 months)
• DO NOT rely on FLAIR for neonatal stroke diagnosis
• This is a classic exam trap - examiner will ask "why was FLAIR normal?" Answer: expected - neonatal FLAIR has poor sensitivity for acute infarct

---

SWI (Susceptibility Weighted Imaging)

1. Hemorrhagic transformation - petechial or confluent hemorrhage within the infarct (dark blooming spots within the DWI lesion)
2. Cerebral venous thrombosis - deoxyhemoglobin in thrombosed sinus = dark sinus on SWI (confirms CSVT)
3. Cortical venous thrombosis - individual cortical veins thrombosed (often missed on MRA/MRV)
4. Microhemorrhages
5. Hypoxic injury markers (lenticulostriate vasculopathy)

• Hemorrhagic transformation on SWI is a relative contraindication to anticoagulation
• CSVT diagnosis on SWI changes management entirely (LMWH indicated)
• Always acquire SWI in every neonatal brain MRI

---

MRA (MR Angiography)

• May show absent or diminished signal in the affected MCA segment (clot causing flow void)
• A filling defect or abrupt signal cutoff confirms arterial occlusion
• A normal MRA does NOT exclude NAIS - the embolus may have already lysed by the time MRI is done (emboli are soft, often dissolve in first 24-48 hours)
• Small distal MCA branch occlusions may be below MRA resolution

---

MRV (MR Venography)

• Absent flow signal in the thrombosed sinus (normally appears as a bright flow-related signal)
• Combined with SWI (dark thrombus in sinus) = definitive diagnosis

---

7.3 Evolution of MRI Over Time - Summary Table

---

7.4 MCA Territory: Why the MCA is Most Commonly Involved

1. The MCA is the direct continuation of the ICA after it enters the skull through the carotid siphon. An embolus traveling from the heart or great vessels through the ICA has a straight path into the MCA.
2. The MCA receives ~70-80% of the cerebral blood flow - sheer volume predicts embolic frequency
3. The angle of take-off of the MCA from the ICA is gentler than the ACA → emboli continue into MCA rather than bending into ACA
4. In the fetal circulation, the ICA directly feeds the MCA - no aortic arch branching creates obstruction

• The left common carotid artery arises directly from the aortic arch (no innominate artery intermediary) → more direct embolic trajectory
• Some evidence suggests fetal head positioning (left occiput anterior) influences umbilical-carotid flow dynamics
• Still not fully explained - this is a recognized epidemiological observation, not completely mechanistically resolved

• M1 segment: Horizontal; gives off lenticulostriate arteries (deep perforators to basal ganglia, internal capsule)
• M2 segments: Superior and inferior divisions in the Sylvian fissure
• M3 segments: Cortical branches over the surface
• Upper division: Precentral, central, anterior parietal branches → motor/sensory cortex
• Lower division: Temporal, posterior parietal branches → Broca/Wernicke areas (left), auditory cortex

---

---

SECTION 8: SEIZURE MANAGEMENT

---

8.1 The Biology of Neonatal Seizures - Why It Matters for Treatment

• Chloride homeostasis in neurons is controlled by two transporters:
  • NKCC1 (Na-K-2Cl cotransporter 1): IMPORTS Cl⁻ into neurons
  • KCC2 (K-Cl cotransporter 2): EXPORTS Cl⁻ from neurons
• In mature neurons: KCC2 > NKCC1 → intracellular Cl⁻ is LOW → when GABA-A opens Cl⁻ channel → Cl⁻ flows IN → hyperpolarization → inhibition
• In neonatal neurons: NKCC1 > KCC2 → intracellular Cl⁻ is HIGH → when GABA-A opens → Cl⁻ flows OUT → depolarization → excitation
• GABA is EXCITATORY in neonates

1. Phenobarbitone (GABA-A enhancer) partially works because at high concentrations it also blocks Na/Ca channels and AMPA receptors - but its primary GABA mechanism is compromised
2. Benzodiazepines are also less effective for same reason
3. Bumetanide (NKCC1 inhibitor) was designed to fix this - but failed in clinical trial (NEMO)
4. This matures over the first weeks-months postnatally (NKCC1 downregulates, KCC2 upregulates)

---

8.2 Antiseizure Medications - Complete Drug Profile

PHENOBARBITAL (PHENOBARBITONE) - First-Line

• Enhances GABA-A receptor Cl⁻ conductance (positive allosteric modulator)
• At higher doses: blocks AMPA/kainate receptors; reduces Na⁺ channel conductance
• Also reduces neuronal firing rate directly

• Loading dose: 20 mg/kg IV over 15-30 minutes
• If seizures persist: Additional 10 mg/kg IV × 1-2 doses
• Maximum total loading: 40 mg/kg
• Maintenance: 3-5 mg/kg/day once daily (long half-life) or BD
• Therapeutic level: 15-40 mg/L (some use 20-40 for active seizures)
• IV rate: ≤1 mg/kg/minute (avoid cardiac adverse effects)

• Half-life: 40-200 hours in neonates (hepatic immaturity → prolonged elimination)
• Volume of distribution: 0.8-1.0 L/kg
• Protein binding: low in neonates (reduced albumin binding capacity)
• Elimination: hepatic CYP2C19/CYP2C9 + renal; autoinduction of metabolism

1. Respiratory depression (most important acute risk) → have bag-mask ready
2. Hypotension (vasodilation) → avoid in hemodynamically compromised babies
3. Sedation → impairs neurological assessment; masks ECD
4. Neuroapoptosis (animal data, Bittigau et al. 2002, PNAS) → PB induces apoptosis in developing rodent brain; human clinical significance debated but genuine concern

---

LEVETIRACETAM - Second-Line (ILAE 2023 consensus; inferior to PB by NeoLEV2)

• Binds synaptic vesicle glycoprotein SV2A → modulates presynaptic neurotransmitter vesicle release
• Also inhibits N-type voltage-gated Ca²⁺ channels
• Inhibits AMPA receptor activation indirectly
• Does NOT act on GABA directly → avoids NKCC1/KCC2 paradox (theoretically advantageous)

1. SV2A receptor is developmentally expressed - lower expression in immature neonatal brain → less binding target
2. Mechanistic mismatch - In acute ischemic seizures, the dominant driver is glutamate/NMDA excitotoxicity and ionic dysregulation, not primarily SV2A-mediated vesicle release. LEV's mechanism doesn't target the acute ischemic seizure generator well.
3. Underdosing historically - Early studies used 20 mg/kg loading; higher doses (40-60 mg/kg) may be needed

• Loading: 20-60 mg/kg IV (most centers use 20-40 mg/kg; pharmacokinetic modelling suggests higher doses may be needed)
• Maintenance: 10-30 mg/kg/day in BD dosing
• Half-life: 10-20 hours in neonates (renal clearance immature → longer than adults)
• Protein binding: <10% → minimal drug interactions

• Less respiratory depression
• No sedation
• Less apoptosis in animal models
• Safe in renal disease if dose-adjusted

• NeoLEV2 (NEJM 2020): 28% vs 80% for PB → clearly inferior
• Cochrane Review (Abiramalatha et al., 2023): confirms PB superior
• Systematic review (Kumar et al., Indian J Pediatr 2025): PB superior in multiple outcomes

---

LACOSAMIDE - Third-Line / Add-on (Growing Evidence)

• Selective enhancement of slow inactivation of voltage-gated sodium channels (Nav1.1, Nav1.2, Nav1.3, Nav1.6)
• This is distinct from phenytoin/carbamazepine which enhance fast inactivation
• Slow inactivation: the Na channel remains inactive (non-firing) for a longer period after each action potential → reduces repetitive firing of hyperexcitable neurons
• Also binds CRMP-2 (collapsin response mediator protein 2) - a neurodevelopmental protein; exact role in seizure suppression is being studied

• Complementary mechanism to PB (GABA-A) and LEV (SV2A) - different molecular target
• Can be given IV - important in acute NICU setting
• Has oral formulation available - can transition to oral maintenance
• Growing clinical data in neonates

• Loading dose: 8-10 mg/kg IV (some case series use up to 15 mg/kg)
• Maintenance: 5-8 mg/kg/day in BD dosing
• Half-life: estimated 14-20 hours in neonates (limited PK data)
• Protein binding: <15%
• Elimination: 40% renal (unchanged), 30% CYP2C19

• Lacosamide prolongs the PR interval through slow Na-channel inactivation in cardiac conduction tissue (SA node, AV node)
• Risk: First-degree AV block (PR >200 ms), potentially higher degrees
• Protocol: ECG BEFORE and 2-4 hours AFTER lacosamide loading
• Neonatal normal PR: 70-130 ms
• If PR >130 ms after loading → reduce dose; if AV block develops → stop
• Avoid combining with other Na-channel blockers (phenytoin, carbamazepine) - additive conduction effects
• Any baby with structural CHD + known conduction abnormality → extra caution; cardiology consultation before lacosamide

• Kaur et al., Pediatr Neurol 2024 (multicenter): EEG response in ~50-60% of refractory neonatal seizures; ECG monitoring essential
• Chourasia et al., Pediatr Neurol 2024: ~60% reduction in seizure burden as adjunct
• Bamgbose et al., J Child Neurol 2023: Generally well tolerated; no serious AEs attributable to lacosamide
• Langton et al., Epilepsia 2022: Animal model - lacosamide reduces neonatal seizures WITHOUT increasing apoptosis (unlike PB)

---

MIDAZOLAM - Second or Third-Line (Status Epilepticus)

• Acute bolus: 0.05-0.15 mg/kg IV
• Infusion for refractory SE: 0.01-0.1 mg/kg/hour (titrate up)

1. Same NKCC1/KCC2 paradox as PB (GABA-A agent) → less effective
2. Paradoxical excitation possible due to excitatory GABA
3. Acute tolerance develops rapidly with continuous infusion (hours to days)
4. Respiratory depression and hypotension
5. Active metabolite α-hydroxymidazolam accumulates with infusion (renally cleared)

---

PHENYTOIN / FOSPHENYTOIN - Third-Line (Less Used Now)

• Cardiac arrhythmias during rapid IV infusion (bradycardia, heart block, hypotension) - cardiac monitoring mandatory
• Hypotension
• Gingival hyperplasia (long-term)
• Neonatal PK is unpredictable - Michaelis-Menten (saturable) kinetics; half-life 40-140 hours (highly variable)

---

LIDOCAINE (LIGNOCAINE) - Specialized Use (Europe)

---

BUMETANIDE - Research Only; DO NOT USE Clinically

• Multicentre RCT: bumetanide vs placebo in HIE-associated neonatal seizures
• Result: No efficacy - did not reduce seizure burden
• Significant ototoxicity (sensorineural hearing loss) - NKCC1 in the cochlea is also inhibited
• Trial stopped early due to harm
• Not recommended clinically

---

8.3 When to Stop Antiseizure Medication

"Antiseizure medications should be discontinued before hospital discharge in neonates whose seizures are controlled and whose neurological condition is improving."

1. Most neonatal seizures are acute symptomatic - caused by the acute brain injury. When the acute injury stabilizes (Day 3-7 in NAIS), seizures typically stop
2. Prolonged PB exposure worsens neurodevelopment - animal data show PB-induced apoptosis; observational human studies suggest longer PB use correlates with worse outcomes
3. The risk of recurrent neonatal seizures after discharge is low if the EEG has normalized
4. Post-neonatal epilepsy (if it develops) will manifest later and can be treated at that time with appropriate age-appropriate medications

• EEG still shows interictal epileptiform discharges or ongoing seizures
• Large infarct with evidence of cortical injury predisposing to early epilepsy
• Known epileptic encephalopathy syndrome (KCNQ2, CDKL5, SCN2A)
• Family/neurological team unable to monitor clinically

1. Achieve seizure control (PB ± additional agents)
2. Confirm seizure cessation on cEEG for 24-48 hours seizure-free
3. If EEG background improving and no seizures for 24-48 hours → plan ASM taper before discharge
4. Neurological and EEG follow-up at 1-3 months

---

---

SECTION 9: STROKE-SPECIFIC MANAGEMENT

---

9.1 Supportive Care - Target by Target

---

9.2 Should Thrombolysis (tPA) Be Used in Neonatal Stroke?

1. The neonatal hemostatic system is immature - fibrinolytic capacity and platelet function differ from adults; risk of hemorrhage is substantially higher
2. The time window has usually passed by the time NAIS is diagnosed (Day 1-3 presentation + diagnostic workup = already 12-48 hours from onset)
3. No evidence of safety or efficacy in neonates (no clinical trials)
4. Hemorrhagic transformation risk: MCA infarcts already have 20-30% rate of petechial hemorrhage on SWI; tPA would dramatically worsen this
5. In adults, tPA is given within 4.5 hours - an impossible window in neonates who are clinically silent initially

---

9.3 Should Mechanical Thrombectomy Be Used?

1. No clinical trials in neonates
2. MCA caliber in neonates is too small for current thrombectomy devices
3. The embolus has usually lysed by the time of diagnosis
4. The neonatal vascular anatomy (thin vessels, tortuous) makes endovascular access extremely high risk
5. In childhood AIS (>12 years, large vessel occlusion), thrombectomy is considered - but this does not extend to neonates

---

9.4 Role of Anticoagulation (LMWH)

• Active intracranial hemorrhage or large hemorrhagic infarction
• Thrombocytopenia (<50,000/µL) - relative
• Uncorrected DIC
• Large NAIS with expected hemorrhagic transformation

• Therapeutic (treatment): 1.5 mg/kg/dose SC every 12 hours (neonates need higher weight-adjusted doses due to larger Vd and higher anti-Xa clearance)
• Prophylactic: 0.75 mg/kg/dose SC every 12 hours
• Monitor: Anti-Xa level (target therapeutic: 0.5-1.0 IU/mL; drawn 4 hours post-dose)
• Reverse with: protamine sulfate (1 mg per 1 mg enoxaparin given in last 8 hours)

---

9.5 Role of Aspirin

1. Aspirin is an antiplatelet agent; NAIS is primarily embolic (not platelet-driven thrombosis at the site)
2. The stroke has already occurred; aspirin prevents recurrence but recurrence risk in uncomplicated NAIS is only ~1-3%
3. Risk: hemorrhagic transformation of infarct; Reye syndrome (theoretical but low risk in neonates)

• Presumed Perinatal Stroke presenting in later infancy - when child presents at 6 months with hemiplegic CP attributable to previous perinatal stroke, aspirin (1-5 mg/kg/day) may be used for secondary prevention
• Post-cardiac surgery with identified embolic mechanism
• Moyamoya disease in older children (not neonates)

---

---

SECTION 10: CARDIAC EVALUATION

---

10.1 Why Echocardiography Is Performed in Every NAIS Baby

---

10.2 Which Cardiac Conditions Predispose to NAIS?

PATENT FORAMEN OVALE (PFO):

• Present in virtually all neonates at birth (functional closure begins at first breath)
• In normal transition: LA pressure rises → PFO closes functionally within hours; anatomical closure over weeks-months
• During the transition period: any event causing right-to-left pressure reversal (crying, Valsalva-like, pulmonary hypertension, vigorous sucking) can open the PFO transiently
• A venous thrombus (from placenta, UAC, deep veins) can traverse: umbilical vein → IVC → RA → PFO → LA → aorta → ICA → MCA
• This is the paradoxical embolism mechanism
• Echo finding: color Doppler shows right-to-left shunting through an interatrial communication with bubble study

PFO vs ASD:

CYANOTIC CONGENITAL HEART DISEASE:

• Mechanisms:
  1. Right-to-left intracardiac shunting → venous blood bypasses pulmonary circulation → emboli go directly to systemic (cerebral) circulation
  2. Polycythemia (compensatory for chronic hypoxia) → hyperviscosity → cerebral thrombosis
  3. Perioperative: Cardiopulmonary bypass, cannulation, anticoagulation fluctuations
• Specific lesions with highest stroke risk:
  • Hypoplastic Left Heart Syndrome (HLHS) - extreme hemodynamic instability; Norwood procedure carries significant neurological risk
  • Transposition of Great Arteries (TGA) - before and after arterial switch operation
  • Tetralogy of Fallot - right-to-left shunting across VSD
  • Total anomalous pulmonary venous return (TAPVR) - obstructed forms
  • Single ventricle physiology - any stage of Fontan palliation

INTRACARDIAC THROMBUS:

• May form in the setting of cardiomyopathy (dilated), post-cardiac surgery, or long-standing CHD
• LV thrombus → systemic embolism → cerebral arterial occlusion
• Echo: echo-bright mobile or fixed mass in cardiac chamber
• Management: LMWH anticoagulation + treat underlying cardiac cause

BACTERIAL ENDOCARDITIS:

• Rare in neonates (organisms: Staph. aureus, CoNS from line infection)
• Vegetations on tricuspid valve (right-sided from UAC/UVC) can embolize → paradoxical embolism via PFO
• Echo: valve vegetations; blood cultures positive
• Management: antibiotics + LMWH

ECMO (Extracorporeal Membrane Oxygenation):

• Highest neurological risk procedure in neonates
• ECMO-associated stroke mechanisms:
  1. Cannulation of right ICA/right IJV for VV/VA ECMO → direct vessel injury + thrombus
  2. Circuit thrombus can embolize
  3. Anticoagulation fluctuations → thrombosis when subtherapeutic; hemorrhage when supratherapeutic
  4. Circuit air entry
• NAIS occurs in ~5-10% of ECMO neonates; MRI should be done before and after ECMO

---

---

SECTION 11: THROMBOPHILIA WORKUP

---

11.1 Complete Investigation List with Interpretation

PROTEIN C:

---

PROTEIN S:

---

ANTITHROMBIN III (ATIII):

---

FACTOR V LEIDEN (G1691A Mutation):

---

PROTHROMBIN G20210A MUTATION:

---

HOMOCYSTEINE:

• MTHFR C677T homozygous (especially if B12/folate deficient)
• CBS deficiency (classical homocystinuria - presents with lens dislocation, Marfan habitus, thrombosis in childhood)
• Nutritional B12/folate deficiency

---

MTHFR C677T AND A1298C MUTATIONS:

• AHA 2019 and most guidelines do NOT recommend routine MTHFR testing in neonatal or pediatric stroke workup
• Reason: Heterozygous MTHFR C677T alone does not significantly elevate plasma homocysteine in most individuals; the elevated homocysteine is the risk factor, not the mutation itself
• Only clinically relevant when plasma homocysteine is actually elevated
• MTHFR mutation without hyperhomocysteinemia has no independent thrombotic risk

---

ANTIPHOSPHOLIPID ANTIBODIES (APS):

1. Anticardiolipin antibodies (aCL) - IgG and IgM
2. Anti-β2-glycoprotein I antibodies (anti-β2GP1) - IgG and IgM
3. Lupus anticoagulant (LA) - functional test (prolonged aPTT not corrected by mixing study)

• A single positive test in the neonatal period may represent transient maternal transfer
• Must repeat at 12 weeks (maternal antibodies will have cleared by then)
• Only positive at 12 weeks = persistent neonatal APS (rare; requires investigation for maternal APS)
• Test the mother - maternal APS is an independent risk factor for NAIS via placental thrombosis

---

LIPOPROTEIN(a) [Lp(a)]:

• Not part of standard coagulation panel but increasingly recognized as an independent pediatric stroke risk factor
• Lp(a) inhibits fibrinolysis (structural similarity to plasminogen → competes for fibrin binding → plasmin cannot dissolve clots)
• Elevated Lp(a) found in ~25% of children with AIS
• Test: Lp(a) serum level → elevated >30 mg/dL or >75 nmol/L is considered elevated
• AHA 2019: Lp(a) testing is recommended in pediatric/neonatal stroke workup

---

WHICH TESTS ARE UNRELIABLE IN THE NEONATAL PERIOD:

• Factor V Leiden (PCR)
• Prothrombin G20210A (PCR)
• MTHFR (PCR)

---

---

NEONATAL ARTERIAL ISCHEMIC STROKE

Complete DM Neonatology Teaching Document - Part 2

Sections 12 through 22

---

SECTION 12: PLACENTAL PATHOLOGY

---

12.1 Why Placental Histopathology Is the Single Most Important Etiological Investigation

• Placental pathology is abnormal in 65-80% of NAIS cases when examined systematically
• Fetal Thrombotic Vasculopathy (FTV) - the most specific finding - is present in 10-65% across series
• Normal placental histology is actually reassuring and reduces the list of thrombotic differentials
• AHA 2019 and international stroke guidelines: placental examination is recommended in all neonates with NAIS

• Placenta is regarded as a "waste product" after delivery
• Many hospitals do not have a systematic protocol for placental retention and pathology referral
• NAIS diagnosis may only be confirmed at 24-48 hours after delivery, by which time the placenta may have been discarded

---

12.2 Placental Findings That Support NAIS

---

12.3 How to Report Placental Findings

---

---

SECTION 13: PROGNOSIS

---

13.1 Mortality

• NAIS alone (without major CHD or severe birth asphyxia) has a low mortality rate: ~5-10%
• Deaths are typically from associated conditions (severe cardiac disease, sepsis, severe HIE concurrent with stroke)
• Isolated NAIS in an otherwise well term neonate is not a fatal condition

---

13.2 Risk of Recurrent Stroke

• Recurrence risk after NAIS: ~1-3% (extremely low)
• This is dramatically lower than adult stroke recurrence (10-15% at 1 year)
• Reasons for low recurrence:
  • Most NAIS is secondary to a perinatal event that is non-recurring (FTV resolves with placenta delivery, transitional PFO closes, perinatal asphyxia is over)
  • Once the transitional circulation completes, the paradoxical embolism risk disappears
  • The underlying thrombophilic state of pregnancy is no longer present
• When recurrence risk is HIGHER (~5-10%):
  • Documented major thrombophilia (homozygous FVL, ATIII deficiency)
  • Structural CHD with ongoing embolic risk
  • Persistent APS antibodies

---

13.3 Risk of Post-Neonatal Epilepsy

• ~25-46% of children with NAIS develop post-neonatal epilepsy
• Most commonly cited: ~30-35%
• Onset: Usually in the first 1-2 years of life (not immediately after the neonatal period)
• Most seizures are focal (consistent with the cortical origin of injury)
• Most post-stroke epilepsy is pharmacologically controllable with one or two ASMs

• Large infarct (>1/3 of MCA territory)
• Cortical involvement (vs pure subcortical)
• Temporal lobe involvement (most epileptogenic cortex)
• Interictal epileptiform discharges on EEG at 3 months
• Early high seizure burden in the neonatal period

---

13.4 Hemiplegic Cerebral Palsy

• NAIS is the most common identifiable cause of hemiplegic (unilateral spastic) cerebral palsy
• Risk of hemiplegic CP after unilateral MCA infarction: ~50-75%
• More precisely: depends on which MCA territory is involved
  • Corticospinal tract (internal capsule + corona radiata) involvement → nearly 100% risk of hemiplegia
  • Cortical-only infarction → lower risk (~30-50%) due to cortical reorganization

• Right MCA infarct (your case) → left-sided hemiplegia

• T1 signal in posterior limb of internal capsule (PLIC): Normally T1 bright (myelinated in term baby). Loss of T1 brightness in PLIC on the infarcted side = highly predictive of hemiplegia.
• Wallerian degeneration of the corticospinal tract: seen on T2/DTI at 3 months; asymmetric CST volume on DTI is most accurate predictor of motor outcome

• Infants have remarkable cortical reorganization capacity
• Language cortex in particular can shift to the contralateral hemisphere after early left hemisphere injury
• Motor recovery is less plastic but still remarkable with early intervention

---

13.5 Motor Outcomes (Detailed)

---

13.6 Cognitive Outcomes

• IQ within normal range (>85): ~50-60% of NAIS survivors
• Even with normal IQ, specific deficits are common:
  • Executive function impairment (planning, working memory, cognitive flexibility)
  • Processing speed below age expectation
  • Attention and concentration difficulties
• Left MCA infarction: Greater risk of language-linked learning difficulties, reading/spelling impairment
• Right MCA infarction: Greater risk of visuo-spatial, constructional, and non-verbal reasoning deficits

---

13.7 Language Outcomes

• Left MCA infarction - greatest risk:
  • Expressive language delay (Broca's area - left inferior frontal gyrus)
  • Receptive language delay (Wernicke's area - left posterior superior temporal gyrus)
  • Risk: 30-50% language delay
• Remarkable recovery possible: Neonatal plasticity allows right hemisphere to take over language function after early left hemisphere injury - "right hemisphere language shift"
  • This phenomenon is essentially impossible in adult stroke (where language is strictly lateralized)
  • However, right hemisphere language is not equivalent to left hemisphere language - subtle deficits in pragmatics, prosody, complex comprehension persist

---

13.8 Behavioral Outcomes

• ADHD: ~30% (3-4x population risk)
• Anxiety disorders: Elevated
• Autism Spectrum Disorder: Slightly elevated, especially with large bilateral or posterior infarcts
• Behavioral dysregulation (impulsivity, emotional lability)
• These behavioral sequelae are often more functionally disabling than the motor deficit by school age
• ADHD may respond to stimulant medication in these children (same pharmacological approach as idiopathic ADHD)

---

13.9 Predictors of Poor Prognosis

---

---

SECTION 14: LONG-TERM FOLLOW-UP

---

14.1 Follow-Up Schedule

---

14.2 Specific Therapeutic Referrals

PHYSIOTHERAPY:

• Start by 3-4 months (as early as possible)
• Prevents joint contractures on the affected side
• Promotes active use of affected limb
• Constraint-Induced Movement Therapy (CIMT): At 12-18 months; constraining the stronger limb (glove/cast) forces use of the hemiplegic limb → cortical reorganization → improved hand function. Evidence-based from multiple RCTs in hemiplegic CP.
• Modified CIMT (mCIMT): For younger babies; shorter constraint periods; less intensive

OCCUPATIONAL THERAPY (OT):

• Fine motor skills; hand function; activities of daily living
• Adaptive equipment if needed
• School-age: handwriting support; computer aids; occupational adaptation

SPEECH AND LANGUAGE THERAPY:

• Feed assessment first (dysphagia, aspiration risk - in 50% of NAIS babies with cortical involvement)
• Language therapy from 6-12 months
• Augmentative and alternative communication (AAC) if verbal language is severely delayed
• Oral motor therapy for feeding difficulties

HEARING:

• Neonatal hearing screen before discharge (routine UNHS)
• If PB used extensively: follow-up OAE/AABR (PB does not directly cause hearing loss but seizure burden from underlying injury may affect auditory pathways)
• If bumetanide was used: formal audiology at 3 months (ototoxicity risk)

VISION:

• Formal ophthalmology assessment at 6-12 months
• Visual field defects (homonymous hemianopia) may occur with PCA/parieto-occipital involvement
• Cortical visual impairment if extensive parieto-occipital infarction

PSYCHOLOGY/NEUROPSYCHOLOGY:

• Formal neuropsychological assessment at school entry (5-6 years)
• Identifies specific cognitive deficits for educational planning
• ADHD assessment at 5-7 years if behavioral concerns

---

---

SECTION 15: PARENT COUNSELLING

---

15.1 Framework for Counselling

1. Honesty with hope - Do not give false reassurance, but do not catastrophize either. NAIS has a wide range of outcomes and remarkable plasticity potential.
2. Acknowledge uncertainty - Many outcomes cannot be predicted precisely in the first days. Be honest about this.
3. Empower with action - Parents feel helpless. Give them concrete things they can do (physiotherapy, early intervention, follow-up) that make a difference.

---

15.2 Key Questions and Answers

"A small blood clot blocked one of the arteries in your baby's brain around the time of birth. This is called a neonatal stroke. It is not caused by anything you did or did not do during pregnancy - these strokes are related to the normal biological processes that happen during delivery: the placenta, the blood's tendency to clot more during labor, and the way blood vessels connect in a newborn's heart. We are doing thorough tests to find if there is a specific cause we can address."

"No. This is not your fault, and it is not anything the medical team caused. Neonatal strokes occur in the context of the transition from fetal to newborn life - it is a biological event. In many families we never find a single cause - it appears to be a combination of factors that converged around the time of delivery. Please do not carry blame for this."

"The risk of this baby having another stroke is very low - around 1 to 3 in 100. The reason is that the conditions that caused this stroke - the placenta, the way the blood was flowing during delivery, the small opening between the heart chambers that normally closes after birth - these have all changed now. Once we complete our investigations, if we find a specific clotting problem, we will address it to reduce even that small risk."

"This is an important question and it depends on what our investigations find. If we find a genetic clotting condition in your baby, we will test both of you as parents as well. If one of you carries the mutation, future pregnancies can be monitored with specialist input. Most mothers of babies with neonatal stroke go on to have healthy pregnancies and babies. Once all results are back, I will arrange a consultation with our specialist to guide you through this specifically."

"The honest answer is that we cannot tell you for certain today, but we can tell you that the majority of babies with this type of stroke do walk independently. Many walk by 18-24 months, though one side of the body may be weaker. The brain at this age has extraordinary ability to reorganize - pathways can reroute, and early physiotherapy takes advantage of this. We will start physiotherapy referral early. The 3-month MRI will give us much more specific information about what to expect for movement. We are not giving up on walking - we are working toward it."

"There is about a 1 in 3 chance - approximately 30% - that your baby may develop recurring seizures later in the first 1-2 years. If that happens, it is usually manageable with medication. The seizures your baby is having now are related to the acute injury and are expected to settle. We plan to stop the medications before discharge if seizures are controlled. If epilepsy develops later, we will treat it at that time and it is very often well controlled."

"Approximately half to two-thirds of children with this type of stroke have intelligence in the normal range. Even those who have lower scores often have specific areas of difficulty rather than global intellectual disability. Language development is something we will watch closely and support with speech therapy. Your child may have some learning difficulties at school that we can identify and support early. We will do formal developmental testing as your child grows, so nothing is missed."

---

15.3 Sample Counselling Conversation

---

---

---

SECTION 16: DIFFERENTIAL DIAGNOSIS

---

16.1 Complete Comparison Table

---

---

SECTION 17: EVIDENCE AND LANDMARK TRIALS

---

17.1 Landmark Trials - Complete Summary Table

---

---

SECTION 18: RECENT ADVANCES

---

18.1 Neonatal Neurocritical Care (Neonatal NeuroCritical Care - NNCC)

• Neurofocused hemodynamic management: Maintain cerebral perfusion pressure; avoid hypotension; target organ (brain) centered BP management
• Neuromonitoring bundle: Continuous EEG + aEEG + NIRS (near-infrared spectroscopy) for real-time cerebral oxygenation monitoring
• Seizure response protocols: Standardized ASM escalation algorithms based on EEG response, not clinical response
• Neuroprotective bundles: Normoglycemia, normoxia, normothermia, normocapnia, sodium control - all simultaneously

---

18.2 Continuous EEG Monitoring

• cEEG is now considered standard of care in any NICU with capacity
• Seizure detection algorithms (automated) can alert the team within minutes of EEG seizure onset
• Reduces time to treatment → reduces cumulative seizure burden
• EEG-based prognostication: background pattern (normal/mildly-moderately/severely abnormal) is a strong predictor of outcome independent of MRI

• Remains useful as a monitoring bridge when full cEEG technologist coverage is unavailable
• Newer 4-channel aEEG devices improve spatial resolution significantly over 2-channel
• Machine learning algorithms for automated seizure detection on aEEG: sensitivity reaching 85-90% in recent studies

---

18.3 Advanced MRI Techniques

Diffusion Tensor Imaging (DTI):

• Maps white matter tracts quantitatively
• Fractional anisotropy (FA) of the corticospinal tract at 3 months: most accurate early predictor of motor outcome in NAIS
• Asymmetry index of CST (comparing affected vs unaffected hemisphere): >25% asymmetry predicts hemiplegia
• Available at most tertiary centers; requires dedicated post-processing

MR Spectroscopy (MRS):

• Measures metabolite peaks: N-acetylaspartate (NAA - neuronal integrity), lactate (anaerobic metabolism), choline (membrane turnover), creatine (energy metabolism)
• In acute infarct: Lactate peak present; NAA reduced in infarct zone
• Elevated lactate in metabolic stroke (MELAS, pyruvate dehydrogenase deficiency) → helps differentiate from NAIS
• Lactate/NAA ratio at 24-72 hours correlates with neurodevelopmental outcome

Quantitative MRI:

• T1/T2 relaxometry - quantitative measures of myelination progress
• Magnetic transfer imaging - white matter microstructure
• Research tools; not yet standard clinical practice

Arterial Spin Labelling (ASL):

• Non-contrast measure of cerebral blood flow
• Shows perfusion in the penumbra; identifies hypoperfused but viable tissue
• In NAIS: May show reduced CBF in MCA territory with maintained perfusion in penumbra
• Research/advanced clinical tool; increasingly available

---

18.4 Biomarkers in Neonatal Stroke

---

18.5 Neuroprotection Research

• Therapeutic hypothermia is for HIE, not NAIS
• Supportive care bundles (normoglycemia, normoxia, normothermia) are the extent of current evidence

1. Erythropoietin (EPO) and Darbepoetin: Neuroprotective in HIE animal models; several trials in neonatal brain injury; PENUT trial (preterm) and others; specific NAIS trials lacking
2. Melatonin: Antioxidant and neuroprotective; small trials in HIE; anti-inflammatory; safe; may be relevant in NAIS
3. Remote ischemic preconditioning: Concept of protecting brain against ischemic injury through brief ischemia in a limb; theoretical relevance to post-stroke neuroprotection
4. Xenon gas: Neuroprotective via NMDA receptor blockade; MagnaXon trial; combines with TH in HIE; NAIS-specific data lacking
5. Cannabidiol (CBD): Anti-seizure (FDA-approved for Dravet, LGS); neuroprotective potential via CB1/CB2 receptors; preclinical data in neonatal stroke; no clinical trial yet

---

18.6 Stem Cell Therapy

• Animal (preclinical) data: Mesenchymal stem cells (MSCs) reduce infarct volume, improve motor outcomes in rodent NAIS models (Lehnerer et al., Pediatr Res 2024 - meta-analysis of preclinical studies confirms this)
• Human clinical trials: Insufficient evidence - no adequately powered RCT in neonates
• Safety concerns: route of delivery, tumorigenicity, immune reactions

---

18.7 AI-Assisted Imaging and Seizure Detection

• Machine learning seizure detection algorithms have FDA-cleared devices (BrainStatus, Persyst, Natus)
• In neonatal EEG: multiple proprietary algorithms with sensitivity 80-90%, specificity 70-80% for automated seizure detection
• Key limitation: Training data dominated by adult/older pediatric EEGs; neonatal EEG patterns are unique; performance in neonates lower than in adults
• Federated learning approaches (training on multicenter neonatal EEG databases) are improving performance

• Automated segmentation of neonatal brain MRI: AI tools can automatically segment cortex, white matter, basal ganglia, cerebellum
• Infarct volume automated quantification
• Prediction models combining imaging + clinical features for neurodevelopmental outcome prediction
• Research tool currently; validation for clinical use ongoing

---

---

SECTION 19: DM NEONATOLOGY VIVA QUESTIONS

---

19.1 - 50 Rapid-Fire Viva Questions

---

19.2 - 20 Image-Based MRI Questions

---

19.3 - 20 Case Scenarios

• Case 11: NAIS + abnormal ECG (prolonged PR) after lacosamide → management?
• Case 12: NAIS + thrombocytopenia (plt 40,000) + DIC → anticoagulation decision?
• Case 13: Baby with NAIS, seizure-free for 48 hours on cEEG, EEG background normal → when to stop PB?
• Case 14: PPIS presenting at 4 months → what investigations are still useful?
• Case 15: NAIS + congenital HSV infection → does acyclovir change the stroke management?
• Case 16: Baby on ECMO develops focal seizures Day 5 → what is the differential and approach?
• Case 17: Twin B (polycythemic twin in TTTS) develops left arm clonic seizures Day 2 → mechanism?
• Case 18: Baby post-Norwood procedure for HLHS develops MCA infarction → management dilemma re: anticoagulation?
• Case 19: Mother has known APS and delivered at term; neonatal APS antibodies positive → surveillance or treatment?
• Case 20: School-age child referred; learning difficulties + hemiplegic CP → turns out to be undiagnosed PPIS on MRI → what ongoing management?

---

19.4 - 20 Management Dilemmas

---

19.5 - 20 Higher-Order Reasoning Questions

---

---

SECTION 20: CONSULTANT ROUND QUESTIONS

---

20.1 The Ten Most Difficult Consultant Questions with Full Answers

This is the fundamental tension in neonatal seizure management. The Bittigau et al. 2002 PNAS study convincingly showed PB-induced neuroapoptosis in rodent models at doses equivalent to clinical use. This raised legitimate concern. However: (1) rodent studies do not directly translate to human neonates - human brain development timeline differs significantly; (2) observational human studies show equivocal results; some showing worse outcomes with longer PB exposure, others not; (3) the alternative - uncontrolled seizures - causes direct brain injury through excitotoxicity, ischemia, and metabolic disruption; this harm is certain, while PB-induced apoptosis in humans remains debated. The NeoLEV2 trial showed LEV is inferior (28% vs 80% efficacy); so the only effective alternative performs poorly. The ILAE 2023 guideline committee - having reviewed all evidence - concluded the balance of evidence still favors PB as first-line. The pragmatic solution: use PB effectively, achieve seizure control, and discontinue as soon as possible (before discharge) to minimize cumulative exposure.

Discharge criteria: (1) Seizures controlled clinically AND on cEEG (minimum 24-48 hours seizure-free); (2) EEG background improving (not severely abnormal/burst suppression); (3) Echo complete; (4) Thrombophilia panel sent (results can return outpatient); (5) Placental histopathology requested; (6) ASM taper plan discussed with parents - ILAE 2023 recommends discontinuing before discharge if criteria met; (7) Follow-up appointments made (neurology, developmental pediatrics, physiotherapy); (8) Parents counselled about seizure recognition and when to return to emergency. The investigation results that are pending do NOT need to be back before discharge - they guide outpatient management.

The adult maximum dose of lacosamide is 200 mg/dose BD. In neonates, there is no established maximum, but case series report using up to 15 mg/kg as a loading dose. I would give a second 5 mg/kg load (total 13 mg/kg) with ECG monitoring before and after each dose. The primary safety check is the ECG PR interval - as long as PR remains within acceptable limits (<150 ms) and there is no AV block, further dosing is defensible. Beyond this, switch to an alternative agent (midazolam infusion or phenytoin). There is no published neonatal maximum dose from RCT data; decisions are made on case-by-case basis with ECG monitoring.

I would not give them a number today on Day 3. What I would say is: the 3-month MRI - specifically the DTI scan looking at the motor pathway (corticospinal tract) - will give us the most accurate probability. If the internal capsule signal is preserved at 2 weeks on T1 and the DTI shows minimal asymmetry at 3 months, the majority of babies with this finding walk normally. If the internal capsule is involved, walking is still possible but hemiplegia is likely. I give them a range (50-75% hemiplegia risk for unilateral MCA stroke), explain that this is statistical and that early physiotherapy can shift outcomes positively, and commit to a specific conversation at 3 months when we have imaging evidence.

No. Aspirin is not indicated in acute NAIS. It is an antiplatelet agent - NAIS is embolic, not platelet-thrombosis driven. The stroke has occurred; aspirin for secondary prevention has a recurrence risk reduction benefit, but since NAIS recurrence risk is only 1-3%, the absolute benefit is negligible. The risk of hemorrhagic transformation of the infarct outweighs any benefit. AHA 2019 does not recommend routine aspirin in acute NAIS. Aspirin may be considered later (at 3-6 months in PPIS presentation, or if CHD with ongoing embolic risk is identified).

---

---

SECTION 21: PRACTICAL NICU PEARLS

---

21.1 Common Mistakes Made by Residents

---

21.2 When to Suspect NAIS Despite Normal Cranial Ultrasound

1. Term baby, Day 1-3, with focal clonic unilateral seizures with no HIE, no metabolic cause, and normal glucose/calcium
2. EEG shows focal ictal discharges over one hemisphere with clinical focal seizure
3. Normal Apgar scores, no acidosis (excludes HIE as primary)
4. Any term baby with focal neurological signs (asymmetric tone, eye deviation, asymmetric suck)
5. Post-cardiac surgery neonate developing new focal seizures
6. Baby on ECMO with new neurological deterioration

---

21.3 Red Flags That Change Management

---

21.4 Clinical Pearls for Rounds

1. "A term baby with focal seizures and no HIE is NAIS until proven otherwise" - this is the clinical axiom
2. The seizure lateralizes the lesion before the MRI is done - left arm = right hemisphere = right MCA
3. Placenta is the patient's placenta too - it contains the crime scene evidence; don't let it be discarded
4. Normal cranial US means nothing in NAIS - US is for premature babies (IVH, PVL); MRI is for term seizures
5. After PB loading, check the EEG, not just the baby - clinical quiet ≠ electrographic quiet
6. FLAIR in neonates is a trap - an examiner will ask why FLAIR is normal in a baby with DWI-confirmed infarct; the answer is: FLAIR is unreliable before 3-6 months
7. ADC pseudonormalization: Days 5-10 - if a family or consultant says "the stroke looks better on MRI at Day 7," explain this phenomenon
8. Stop ASMs before discharge - ILAE 2023; do not discharge a baby on PB without a clear plan to stop it
9. The 3-month MRI is the prognostic timepoint - PLIC signal + DTI asymmetry; plan it before discharge
10. Counsel parents with honesty, structure, and a plan - not just diagnosis, but what you're doing next, what to watch for, and when you'll know more

---

---

SECTION 22: HIGH-YIELD SUMMARY

---

22.1 One-Page Revision Sheet

NEONATAL ARTERIAL ISCHEMIC STROKE - MASTER REVISION

DEFINITION: Focal infarction in territory of named cerebral artery; 20 wks
            gestation to 28 days postnatal; confirmed by neuroimaging

INCIDENCE:  1/2,300 - 1/5,000 live births (~1/4,000)

TIMING:     Day 1-3 of life; PPIS presents at 4-6 months

VESSEL:     Left MCA > Right MCA (>80% of NAIS is MCA territory)

MECHANISM:  Placental FTV → embolism via PFO (paradoxical) → ICA → MCA
            + Neonatal hypercoagulability + Perinatal inflammation

PRESENT:    Focal clonic unilateral seizure (left arm = right MCA)
            Term baby + normal HIE + no metabolic cause

DIAGNOSE:   MRI DWI + ADC (most sensitive; positive within minutes)
            • DWI bright + ADC dark = acute infarct
            • FLAIR unreliable in neonates
            • ADC pseudonorm: Days 5-10 (don't be fooled)
            • T1 cortical laminar necrosis: 1-2 weeks = subacute
            • SWI: hemorrhagic transformation + venous thrombus
            • MRA: MCA occlusion (may be normal if embolus lysed)
            • MRV: CSVT (changes management → LMWH)

EEG:        cEEG mandatory (ECD = clinical gone but EEG continues)
            aEEG: 76-85% sensitivity (not enough alone)

WORKUP:     Glucose STAT (always first)
            CBC, CRP, cultures, coagulation
            Echo (cardiac source in 25-30%)
            Placental histopathology (MOST IMPORTANT, MOST MISSED)
            Thrombophilia: FVL (PCR) + PT mutation (PCR) + Protein C/S/ATIII
              (with neonatal norms, repeat at 3-6 months)
            APS antibodies (repeat at 12 weeks; test mother)
            MTHFR: only if homocysteine elevated (NOT routine per AHA)

ASM THERAPY:
  1st:  PB 20 mg/kg IV → up to 40 mg/kg total (NeoLEV2: 80% vs 28% LEV)
  2nd:  LEV 20-40 mg/kg IV (inferior to PB; safer profile)
  3rd:  Lacosamide 8-10 mg/kg IV (ECG before/after! → PR prolongation)
        Midazolam infusion 0.01-0.1 mg/kg/hr (refractory SE)
  STOP: Before discharge (ILAE 2023) if seizures controlled

MANAGEMENT: No TH, no tPA, no thrombectomy
            Normoglycemia 2.6-5.5 mmol/L
            SpO2 94-99%, normothermia, euvolemia, MAP ≥ GA in mmHg
            LMWH ONLY for: CSVT / cardiac thrombus / major thrombophilia

PROGNOSIS:
    Mortality: ~5-10%
    Recurrence: ~1-3% (very low)
    Epilepsy: ~30-35%
    Hemiplegia: ~50-75% (depends on CST involvement)
    Normal IQ: ~50-60%
    ADHD: ~30%
    PLIC loss of T1 signal at 2 weeks → predicts hemiplegia
    DTI CST asymmetry at 3 months → most accurate motor predictor

FOLLOW UP:  MRI + DTI at 3 months; EEG at 3 months
            Physio from 4 months; CIMT from 12 months
            Annual review until school age

---

22.2 Mnemonics

• S - Seizure type and lateralization
• T - Timing (Day 1-3 = NAIS; Day 4-7+ = think CSVT, infection)
• R - Risk factors (maternal, placental, cardiac, thrombophilia)
• O - Order: Glucose FIRST → MRI → Echo → Placenta → Thrombophilia
• K - Key imaging: DWI bright + ADC dark = ACUTE stroke
• E - EEG mandatory (ECD after ASM loading is common)

---

• P - Placental histopathology
• L - Labs (glucose, calcium, CBC, coagulation)
• A - Angiography (MRA for arteries, MRV for veins)
• C - Cardiac echo (25-30% have cardiac source)
• E - EEG continuous (mandatory)

---

• NKCC1 > KCC2 → High intracellular Cl⁻ → GABA causes depolarization (excitation)
• This matures postnatally as KCC2 upregulates

---

• Cytotoxic edema (days 0-5): ADC ↓ (dark)
• Pseudonormalization (days 5-10): ADC ≈ normal (TRAP!)
• Vasogenic / liquefaction (days 10+): ADC ↑ (bright)

---

22.3 Top 100 Take-Home Points

1. NAIS: Focal cerebral arterial infarction, 20 weeks gestation to 28 days postnatal
2. PPIS: Same but presenting after 28 days (4-6 months usually)
3. CSVT: Venous sinus thrombosis; non-territorial; hemorrhagic; treat with LMWH
4. Fetal circulation: PFO + PDA allow paradoxical embolism in transitional period
5. Neonatal stroke is NOT a miniature adult stroke; different biology, mechanisms, prognosis

---

22.4 Diagnostic Algorithm

TERM NEONATE + FOCAL CLONIC SEIZURES (Day 1-3)
                        ↓
        ═══════════════════════════════
        IMMEDIATE (Bedside, within 5 min)
        ═══════════════════════════════
        • Glucose → if <2.6: IV D10W 2mL/kg BOLUS NOW
        • Airway, SpO2 target 94-99%
        • Temperature: normothermia
        • IV access
                        ↓
        ═══════════════════════════════
        WITHIN 30 MINUTES
        ═══════════════════════════════
        • Serum Na, Ca, Mg, blood gas
        • CBC, CRP, blood culture
        • PT, aPTT, fibrinogen, D-dimer
        • aEEG / cEEG (START NOW)
                        ↓
        ═══════════════════════════════
        ASM IF SEIZURE ONGOING
        ═══════════════════════════════
        Phenobarbitone 20mg/kg IV
        → If persists: PB 10mg/kg × 1-2 (max 40 total)
        → If persists: LEV 20-40mg/kg IV
        → If persists: Lacosamide 8-10mg/kg IV (ECG before/after)
        → Status: Midazolam infusion 0.01-0.1mg/kg/hr
                        ↓
        ═══════════════════════════════
        WITHIN 12-24 HOURS
        ═══════════════════════════════
        MRI BRAIN (PRIORITY)
        DWI + ADC + T1 + T2 + SWI + MRA + MRV
                        ↓
        ┌──────────────────────────────────────────────────────┐
        │                                                      │
   DWI bright +      Absent venous        Normal MRI +
   ADC dark +        sinus on MRV +       ongoing seizures
   arterial          hemorrhagic          → Metabolic screen
   territory         infarction           → Repeat MRI Day 14
   = NAIS ✓          = CSVT              → Genetic panel
        │                  │
   NAIS CONFIRMED     CSVT CONFIRMED
        │                  │
   Supportive         LMWH (enoxaparin
   care +             1.5mg/kg BD) +
   Extended           supportive care
   workup             
        ↓
        ═══════════════════════════════
        WITHIN 48 HOURS
        ═══════════════════════════════
        • Echocardiography
        • ECG
        • Placental histopathology (REQUEST URGENTLY)
        • Thrombophilia panel:
          FVL (PCR), PT mutation (PCR), Protein C, S, ATIII
          (with neonatal reference ranges)
          APS antibodies (aCL IgG/IgM, β2GP1, LA)
          Homocysteine, Lp(a)
          
        ═══════════════════════════════
        BEFORE DISCHARGE
        ═══════════════════════════════
        • Seizure-free ×24-48h on cEEG
        • ASM discontinuation (ILAE 2023) if criteria met
        • Parents counselled
        • MRI at 3 months booked
        • Physiotherapy referral
        • Neurology + developmental follow-up

---

---

• NeoLEV2: PB 80% vs LEV 28%
• ADC pseudonormalization: Days 5-10
• Most missed investigation: Placental histopathology

---

NEONATAL ARTERIAL ISCHEMIC STROKE

Complete DM Neonatology Teaching Document — PART 1

Sections 1 through 11

---

SECTION 1: DEFINITION AND CLASSIFICATION

---

1.1 What Is Neonatal Stroke?

"A group of heterogeneous conditions in which there is focal disruption of cerebral blood flow secondary to arterial or venous thrombosis or embolization, occurring between 20 weeks of fetal life through the 28th postnatal day, confirmed by neuroimaging or neuropathologic studies."

1. Timing - 20 weeks gestation to 28 postnatal days
2. Mechanism - focal arterial or venous disruption
3. Confirmation requirement - imaging or pathology; clinical seizure alone does not make the diagnosis

---

1.2 Classification of the Four Distinct Entities

---

1.3 Why Neonatal Stroke Differs from Childhood Stroke

---

---

SECTION 2: EPIDEMIOLOGY

---

2.1 Incidence

• 1 in 2,300 to 1 in 5,000 live births
• Most authoritative figure: ~1 in 2,500 to 1 in 4,000 term neonates
• More common than any single pediatric cancer
• More common than childhood stroke per population age-year
• Second most common cause of neonatal seizures in term babies (after HIE)
• NAIS is the most common identifiable cause of hemiplegic cerebral palsy

2.2 Age at Presentation

• Acute neonatal presentation: Day 1-3 of life (most common); peak Day 2
• Why Day 2? Perinatal circulatory transition (closure of PDA/PFO, shift from fetal to neonatal circulation) occurs over first 24-72 hours, increasing embolic risk during this window
• Delayed presentation (PPIS): 3-6 months of age, when asymmetric hand use becomes apparent

2.3 Which Babies Are at Highest Risk?

• Term neonates (>37 weeks) - predominantly a term baby problem
• Male sex (slight predominance, ~60%)
• Primigravida mothers (longer labor, higher instrumental delivery rate)
• Maternal thrombophilia carriers
• Babies with congenital heart disease
• Babies of mothers with chorioamnionitis or preeclampsia
• IUGR babies (polycythemia, hyperviscosity)
• Babies receiving ECMO
• Post-cardiac surgery neonates

---

---

SECTION 3: PATHOPHYSIOLOGY

---

3.1 Why Does Stroke Occur Around Birth? The Five Converging Mechanisms

Mechanism 1: Fetal Circulation and Transitional Physiology

• PVR drops → pulmonary blood flow increases → LA pressure rises → PFO begins to close
• Cord clamping → PDA closes
• The transitional period (first 24-72 hours) is hemodynamically unstable

Placental thrombus → umbilical vein → IVC → RA → PFO → LA → aorta → ICA → MCA

Mechanism 2: Relative Neonatal Hypercoagulability

• Fetal hemoglobin has higher O2 affinity → lower O2 delivery → compensatory polycythemia
• Hematocrit at term: 45-65% - when Hct >65%, viscosity increases exponentially
• High fibrinogen and activated coagulation cascade during labor
• Relatively low Protein C and S (natural anticoagulants) - physiologically 40-60% of adult levels
• Net result: a prothrombotic milieu at the time of circulatory transition

Mechanism 3: Placental Thromboembolism

• Thrombin is generated at the placental bed during placental separation
• Fetal thrombotic vasculopathy (FTV) - thrombi in fetal stem villous vessels - can send emboli upstream through umbilical vein → cardiac circulation → cerebral arteries
• Confirmed by placental histopathology in 10-65% of NAIS cases
• The placenta is the "upstream factory" of the embolus

Mechanism 4: Perinatal Inflammation (Chorioamnionitis Pathway)

Mechanism 5: Birth-Related Vascular Injury

• Forceps → ICA/MCA injury → in-situ thrombosis
• Vacuum extraction → carotid dissection
• Shoulder dystocia → carotid stretch injury

---

3.2 The Ischemic Cascade in the Brain

Arterial occlusion
        ↓
Energy failure (ATP depleted in 2-5 minutes)
        ↓
Na-K-ATPase fails → Na⁺/Ca²⁺ enter cells, K⁺ exits
        ↓
Cytotoxic edema (cell swelling) → DWI restriction
        ↓
Glutamate release (excitotoxicity) → NMDA activation → Ca²⁺ flooding
        ↓
Calpain/phospholipase/endonuclease activation → cell death
        ↓
Peri-infarct spreading depolarizations → extend injury zone
        ↓
iNOS activation → nitric oxide/free radicals → oxidative damage
        ↓
Reperfusion injury (if blood flow restores) → ROS burst

• Core: Dead tissue within minutes; electrically silent
• Penumbra: Ischemic but viable; hyperexcitable; the seizure generator

• NKCC1 > KCC2 → GABA is excitatory in neonates
• Excess NMDA receptor density in neonatal cortex
• Immature inhibitory interneurons
• High extracellular glutamate from ischemia activates an already hyperexcitable system

---

---

SECTION 4: RISK FACTORS

---

4.1 Complete Classification

MATERNAL:

PLACENTAL:

FETAL/NEONATAL:

CARDIAC:

GENETIC THROMBOPHILIA:

---

---

SECTION 5: CLINICAL PRESENTATION

---

5.1 The Classical Presentation Triad

1. Focal clonic seizures (present in 70-90%)
2. Term baby, Day 1-3 of life
3. No features of HIE (no perinatal asphyxia, Apgars normal/near-normal, no acidosis)

---

5.2 Seizure Characteristics

---

5.3 Full Range of Presentations

---

5.4 Differentiating NAIS from Common Mimics

---

---

SECTION 6: DIAGNOSTIC APPROACH

---

6.1 Stepwise Algorithm

TERM NEONATE + FOCAL CLONIC SEIZURES (Day 1-3)
                    │
    ┌───────────────────────────────┐
    │   IMMEDIATE STABILIZATION     │
    │  Airway / SpO2 target 94-99%  │
    │  BEDSIDE GLUCOSE NOW          │
    │  IV access + temperature      │
    └───────────────┬───────────────┘
                    │
           Is glucose low?
     YES → IV dextrose 2mL/kg D10W bolus
     NO → Continue
                    │
    ┌───────────────────────────────┐
    │      FIRST INVESTIGATIONS     │
    │  Blood glucose, Na, Ca, Mg    │
    │  CBC + CRP + blood culture    │
    │  PT, aPTT, INR, fibrinogen    │
    │  D-dimer, blood gas           │
    └───────────────┬───────────────┘
                    │
    ┌───────────────────────────────┐
    │  ASM (if seizure ongoing)     │
    │  → PB 20 mg/kg IV first-line  │
    └───────────────┬───────────────┘
                    │
    ┌───────────────────────────────┐
    │     cEEG / aEEG START         │
    │  Confirm electroclinical      │
    │  correlation; detect ECD      │
    └───────────────┬───────────────┘
                    │
    ┌───────────────────────────────┐
    │    MRI BRAIN (PRIORITY)       │
    │  DWI+ADC+T1+T2+SWI+MRA+MRV  │
    └───────────────┬───────────────┘
                    │
         MRI confirms infarct?
                    │
    YES → NAIS CONFIRMED
                    │
    ┌───────────────────────────────┐
    │     EXTENDED WORKUP           │
    │  Echocardiography + ECG       │
    │  Thrombophilia panel          │
    │  Placental histopathology     │
    │  APS antibodies               │
    └───────────────────────────────┘

---

6.2 Why Each Investigation Is Ordered

---

---

SECTION 7: NEUROIMAGING

---

7.1 Why MRI Is Mandatory and CT Is Unreliable

• First 6-12 hours: CT is normal - cannot detect cytotoxic edema
• Neonatal brain is normally hypodense (unmyelinated, water-rich) → subtle infarction invisible
• Sensitivity for acute NAIS in first 24 hours: <30%

• Misses 50-60% of NAIS - cannot reliably detect cortical infarcts
• A normal cranial US does NOT exclude NAIS

---

7.2 Each MRI Sequence - Detailed Teaching

DWI (Diffusion Weighted Imaging)

• Positive within minutes of ischemia
• Peak brightness Days 2-5
• Begins to fade after Day 7
• Always interpret alongside ADC map - T2 shine-through can mimic true restriction on DWI alone
• True restriction = DWI bright + ADC dark

---

ADC Map (Apparent Diffusion Coefficient)

• Low ADC (dark) = restricted diffusion = cytotoxic edema = acute infarct ✓
• High ADC (bright) = free diffusion = normal or chronic encephalomalacia

Day 0-5:    ADC LOW (dark)          ← cytotoxic edema dominates
Day 5-10:   ADC NORMALIZING         ← cytotoxic + vasogenic cancel out
Day 10-14+: ADC HIGH (bright)       ← vasogenic edema + liquefaction dominates

---

T1-Weighted

• Acute (0-48h): Normal or subtly hypointense
• Subacute (5-14 days): Cortical T1 hyperintensity = Cortical Laminar Necrosis
  • Hallmark of subacute infarction
  • Most ischemia-sensitive cortical layers (III, V) undergo necrosis
  • Dead neurons appear T1 bright due to denatured proteins + lipid-laden macrophages
  • Appears as a T1 bright gyral ribbon over the infarct zone
  • Confirms subacute infarction timing (1-2 weeks)
• Chronic: T1 dark cystic encephalomalacia

---

T2-Weighted

• Acute (0-6h): Normal
• 6-24h: Subtle T2 hyperintensity begins
• Days 1-7: Clear T2 bright zone in infarct territory
• Chronic: Very bright (cystic/encephalomalacic)

---

FLAIR (Fluid Attenuated Inversion Recovery)

• The neonatal unmyelinated brain has high water content with long T1 relaxation times - similar to CSF
• The FLAIR inversion pulse designed to null CSF also suppresses the neonatal brain signal
• FLAIR is unreliable and insensitive in neonates under 3-6 months
• DO NOT rely on FLAIR for neonatal stroke diagnosis
• Classic exam trap: "Why was FLAIR normal?" → Expected - neonatal FLAIR has poor sensitivity

---

SWI (Susceptibility Weighted Imaging)

1. Hemorrhagic transformation - petechial/confluent hemorrhage within infarct (dark blooming within DWI lesion)
2. Cerebral venous thrombosis - deoxyhemoglobin in thrombosed sinus = dark sinus (confirms CSVT)
3. Cortical venous thrombosis - individual thrombosed cortical veins
4. Microhemorrhages

• Hemorrhagic transformation → relative contraindication to anticoagulation
• CSVT on SWI → changes management entirely (LMWH indicated)
• Always acquire SWI in every neonatal brain MRI

---

MRA (MR Angiography)

• Time-of-flight MRA (no contrast needed)
• Shows Circle of Willis, MCA (M1, M2), ACA, PCA, basilar

• May show absent/diminished signal in affected MCA segment
• Normal MRA does NOT exclude NAIS - embolus may have already lysed by imaging time
• Small distal branch occlusions may be below MRA resolution

---

MRV (MR Venography)

---

7.3 MRI Evolution Over Time - Master Table

---

7.4 Why the MCA Is Most Commonly Involved

1. MCA is the direct continuation of ICA - emboli travel straight from ICA into MCA
2. MCA receives ~70-80% of cerebral blood flow - sheer volume predicts embolic frequency
3. Angle of MCA take-off from ICA is gentler than ACA → emboli prefer MCA
4. In fetal circulation, ICA directly feeds MCA without major branching obstruction

• Left CCA arises directly from aortic arch (no innominate intermediary) → shorter, more direct embolic trajectory from left heart/aorta
• Possible fetal head positioning influence (left occiput anterior)
• Recognized epidemiological observation; not entirely mechanistically resolved

• M1: Horizontal; gives lenticulostriate arteries → basal ganglia + internal capsule
• Upper division (M2/M3): Precentral, central branches → motor/sensory cortex
• Lower division (M2/M3): Temporal branches → Broca/Wernicke (left); auditory cortex

---

---

SECTION 8: SEIZURE MANAGEMENT

---

8.1 The Biology That Explains Why Drugs Are Partly Ineffective

• NKCC1 (Na-K-2Cl cotransporter 1): IMPORTS Cl⁻ INTO neurons
• KCC2 (K-Cl cotransporter 2): EXPORTS Cl⁻ FROM neurons

---

8.2 Each Antiseizure Drug

PHENOBARBITAL (First-Line - ILAE 2023)

• Loading: 20 mg/kg IV over 15-30 minutes
• Additional: 10 mg/kg IV × 1-2 doses if seizures persist
• Maximum total loading: 40 mg/kg
• Maintenance: 3-5 mg/kg/day once daily (long half-life)
• Therapeutic level: 15-40 mg/L

• Half-life: 40-200 hours (very long; hepatic immaturity)
• Volume of distribution: 0.8-1.0 L/kg
• Protein binding: low (reduced neonatal albumin binding)
• Elimination: hepatic CYP2C19/CYP2C9 + renal

1. Respiratory depression (most important acute risk) - have bag-mask ready
2. Hypotension (vasodilation)
3. Sedation - impairs neurological assessment; masks ECD
4. Neuroapoptosis (Bittigau et al. 2002, PNAS) - develops brain apoptosis in animal models

• NeoLEV2 (NEJM 2020): PB 80% vs LEV 28% seizure cessation → PB clearly superior as first-line

---

LEVETIRACETAM (Second-Line - inferior to PB by NeoLEV2)

1. SV2A expression is lower in immature neonatal brain → less binding target
2. Mechanism mismatch - acute ischemic seizures are driven by glutamate/ionic shifts, not primarily SV2A-mediated vesicle release
3. Historical underdosing (20 mg/kg loading may be insufficient)

---

LACOSAMIDE (Third-Line/Add-on - growing evidence)

• Loading: 8-10 mg/kg IV (some case series up to 15 mg/kg)
• Maintenance: 5-8 mg/kg/day BD
• Half-life: ~14-20 hours in neonates

• Lacosamide prolongs PR interval through slow Na-channel inactivation in SA/AV node
• ECG before AND after every loading dose
• Normal neonatal PR: 70-130 ms
• If PR >130-150 ms after loading → reduce dose; if AV block → stop
• Never combine with phenytoin - additive cardiac conduction effects

• Kaur et al., Pediatr Neurol 2024 (multicenter): ~50-60% EEG response; ECG monitoring essential
• Chourasia et al., Pediatr Neurol 2024: ~60% seizure burden reduction as adjunct
• Bamgbose et al., J Child Neurol 2023: Generally well tolerated
• Langton et al., Epilepsia 2022: Animal model - reduces neonatal seizures WITHOUT increasing apoptosis

---

MIDAZOLAM (Second or Third-Line; SE)

• Bolus: 0.05-0.15 mg/kg IV
• Infusion for SE: 0.01-0.1 mg/kg/hour (titratable)

1. Same NKCC1/KCC2 paradox as PB
2. Rapid acute tolerance with continuous infusion
3. Respiratory depression
4. Active metabolite α-hydroxymidazolam accumulates

---

PHENYTOIN/FOSPHENYTOIN (Third-Line; being displaced by lacosamide)

---

BUMETANIDE (Research only - DO NOT use clinically)

---

8.3 When to Stop Antiseizure Medication

"Antiseizure medications should be discontinued before hospital discharge in neonates whose seizures are controlled and whose neurological condition is improving."

1. Seizures are acute symptomatic - cease when brain injury stabilizes (Day 3-7 in NAIS)
2. Prolonged PB worsens neurodevelopment (apoptosis risk)
3. Risk of recurrent neonatal seizures after discharge is low if EEG normalized
4. Post-neonatal epilepsy manifests later and is treated at that time

• EEG still shows interictal epileptiform discharges or ongoing seizures
• Known epileptic encephalopathy syndrome
• Large infarct with early epilepsy risk markers

---

---

SECTION 9: STROKE-SPECIFIC MANAGEMENT

---

9.1 Supportive Care Targets

---

9.2 Thrombolysis (tPA) - NO

• Immature hemostatic system → high hemorrhagic risk
• Time window impossible to meet (diagnosis too delayed)
• No evidence of safety or efficacy in neonates
• Hemorrhagic transformation risk too high
• AHA 2019 does not recommend thrombolysis in neonatal AIS

---

9.3 Mechanical Thrombectomy - NO

• No clinical trials
• MCA caliber too small for current devices
• Embolus has usually lysed by diagnosis
• Vascular access risks prohibitive

---

9.4 Anticoagulation (LMWH)

• Active intracranial hemorrhage / large hemorrhagic infarction
• Thrombocytopenia <50,000/µL (relative)
• Uncorrected DIC

• Therapeutic: 1.5 mg/kg/dose SC every 12 hours
• Monitor: Anti-Xa level 4 hours post-dose (target: 0.5-1.0 IU/mL)

---

9.5 Aspirin - Not in Acute NAIS

---

---

SECTION 10: CARDIAC EVALUATION

---

10.1 Why Echo Is Done in Every NAIS Baby

---

10.2 Cardiac Conditions That Predispose to NAIS

PFO vs ASD:

Cyanotic CHD - Highest Risk Lesions:

• HLHS - extreme hemodynamic instability
• TGA - before and after arterial switch operation
• Tetralogy of Fallot - R→L shunting across VSD
• TAPVR (obstructed forms)

1. Turbulent flow → thrombus → embolism
2. Polycythemia → hyperviscosity → cerebral thrombosis
3. Perioperative: CPB, cannulation, anticoagulation fluctuations

ECMO - Highest Risk Procedure:

• Cannulation of right ICA/IJV → direct vessel injury
• Circuit thrombus can embolize
• Anticoagulation fluctuations (thrombosis when subtherapeutic; hemorrhage when supratherapeutic)
• NAIS occurs in ~5-10% of ECMO neonates

Intracardiac Thrombus:

• Cardiomyopathy (dilated, EF <30%) → LV thrombus → systemic embolism
• Echo: echo-bright mobile/fixed mass
• Management: LMWH + treat underlying cardiac cause

Endocarditis:

• Rare in neonates; Staph. aureus or CoNS from line infections
• Right-sided vegetations (UAC/UVC) can embolize via PFO paradoxically
• Echo + blood cultures

---

---

SECTION 11: THROMBOPHILIA WORKUP

---

11.1 Complete Investigation List

PROTEIN C:

• Role: Natural anticoagulant; cleaves Factors Va and VIIIa
• Neonatal physiology: Physiologically low (40-60% of adult normal in ALL neonates)
• Interpretation trap: A value of 40-60% is NORMAL for a neonate; adult lower limit (~70%) does NOT apply
• True deficiency: Homozygous (<1%) → purpura fulminans at birth; NOT NAIS alone
• When to test: Repeat at 3-6 months using age-appropriate reference ranges

PROTEIN S:

• Role: Cofactor for Protein C
• Neonatal issue: Physiologically low; free Protein S especially low (most bound to C4b-binding protein)
• Interpretation: Always use free Protein S assay with neonatal reference ranges

ANTITHROMBIN III (ATIII):

• Role: Inhibits thrombin, Xa, IXa, XIa; requires heparin as cofactor
• Neonatal physiology: 40-60% of adult normal
• Clinical pearl: Severe ATIII deficiency (<25%) → heparin resistance (LMWH won't achieve anti-Xa targets)

FACTOR V LEIDEN (G1691A):

• Most common inherited thrombophilia (~5% of Caucasians; ~1-2% South Asian)
• Factor Va resistant to Protein C cleavage → sustained thrombin generation
• Testing: PCR - not affected by acute illness, age, or anticoagulation - valid at any time
• Risk: Heterozygous 4-8x VTE; Homozygous 80x VTE

PROTHROMBIN G20210A:

• Second most common inherited thrombophilia (~2-3% Caucasians)
• Elevated plasma prothrombin II → excess thrombin
• Testing: PCR - valid at any time

HOMOCYSTEINE:

• Test before B12/folate supplementation
• Normal <15 µmol/L
• Elevated → endothelial damage → prothrombotic state
• If elevated → then investigate for MTHFR and nutritional deficiencies

MTHFR:

• AHA 2019: NOT routinely recommended in neonatal/pediatric stroke workup
• Heterozygous MTHFR C677T alone does NOT significantly elevate homocysteine in most individuals
• Only clinically relevant if plasma homocysteine is actually elevated
• Exam answer: "I test homocysteine first. If elevated, I then test MTHFR. MTHFR mutation alone without hyperhomocysteinemia is not an independent risk factor."

ANTIPHOSPHOLIPID ANTIBODIES:

1. Anticardiolipin (aCL) IgG and IgM
2. Anti-β2-glycoprotein I (β2GP1) IgG and IgM
3. Lupus anticoagulant (functional test)

• Single positive test in neonatal period = possible transient maternal transfer
• Must repeat at 12 weeks (maternal antibodies cleared by then)
• Test the mother (maternal APS = independent risk factor for NAIS via placental thrombosis)

LIPOPROTEIN(a):

• Elevated Lp(a) found in ~25% of children with AIS
• Inhibits fibrinolysis (structural similarity to plasminogen → competes for fibrin binding)
• AHA 2019 recommends Lp(a) testing in pediatric/neonatal stroke workup

---

11.2 Which Tests Are Unreliable in the Neonatal Period

• Factor V Leiden (PCR)
• Prothrombin G20210A (PCR)
• MTHFR (PCR - but interpret only if homocysteine elevated)

---