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Neonatology - Full Clinical Medical Student Curriculum

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MODULE 1: NEWBORN RESUSCITATION

The NRP Algorithm (Neonatal Resuscitation Program, 8th ed.)

1. Term gestation?
2. Good muscle tone?
3. Breathing or crying?

• Warm, dry, stimulate
• Position and clear airway (suctioning is NOT routine unless airway obstruction is evident)
• Assess: breathing + heart rate (HR)

• HR >100 + breathing → monitor, supportive O2 if needed
• HR 60-100 or not breathing → start PPV (Positive Pressure Ventilation) with room air (21%)
• HR <60 despite PPV → chest compressions at 3:1 ratio (compressions:breaths)
• HR still <60 → epinephrine (IV/UVC preferred; ETT dose if IV access not available)

Meconium-Stained Amniotic Fluid

Delayed Cord Clamping

• Delay 30-60 seconds for vigorous term and preterm infants
• Do NOT use cord milking in infants <28 weeks (risk of IVH)
• Absolute contraindications include: monochorionic twins, discordant twins >25%, placental abruption, uterine rupture

ETT Size and Depth (Harriet Lane Table 18.1)

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MODULE 2: ROUTINE NEWBORN CARE OF A TERM INFANT

Immediately After Birth

1. Dry, remove wet blankets → skin-to-skin with mother or under radiant warmer
2. Feeding: Breastfeed within 1 hour; 8-12 feeds/day for breastfed infants
3. Vitamin K 1 mg IM (prevents hemorrhagic disease of the newborn)
4. Erythromycin 0.5% eye ointment (prophylaxis against gonococcal ophthalmia neonatorum)
5. Hepatitis B vaccine (first dose in delivery room if medically stable)
6. Umbilical cord care - keep clean and dry; no alcohol recommended

Newborn Screening

• Metabolic screen (PKU, hypothyroidism, galactosemia, etc.) - state-specific
• Critical congenital heart disease (CCHD) screening: pulse oximetry in right hand AND foot at 24-48 hours
• Hearing screen before discharge

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MODULE 3: NEWBORN ASSESSMENT

APGAR Score (Assess at 1 min and 5 min)

• 7-10 = Normal
• 4-6 = Moderate depression
• 0-3 = Severe depression (requires immediate resuscitation)

Birth Weight Classifications

Gestational Age Estimation - Ballard Score

• Neuromuscular maturity (posture, square window, arm recoil, popliteal angle, scarf sign, heel-to-ear)
• Physical maturity (skin, lanugo, plantar surface, breast, eye/ear, genitals)

Gestational Age Classification

• Term: 37 0/7 - 41 6/7 weeks
• Late preterm: 34 0/7 - 36 6/7 weeks
• Preterm: <37 weeks
• Post-term: ≥42 weeks

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MODULE 4: RESPIRATORY DISEASES

4A. Respiratory Distress Syndrome (RDS) / Hyaline Membrane Disease

• Prematurity (most important)
• Maternal diabetes
• Cesarean section without labor
• Perinatal asphyxia
• Male sex, second twin

• Respiratory distress worsening over first few hours of life
• Progresses 48-72 hours → then improves (with brisk diuresis)
• Signs: grunting, nasal flaring, subcostal/intercostal retractions, tachypnea

1. Antenatal corticosteroids (betamethasone 2 doses 24 hours apart) for all mothers at risk of preterm birth <34 weeks
2. Ventilatory support: CPAP (first line for mild-moderate), intubation for severe
3. Surfactant therapy (natural > synthetic) - give within 2 hours of birth for best effect
4. Oxygen support - target SpO2 91-95% in preterm infants

4B. Transient Tachypnea of the Newborn (TTN)

• Delayed resorption of fetal lung fluid
• Common in late preterm and term infants born by C-section
• Self-resolving within 24-72 hours
• CXR: hyperinflation, perihilar streaking, fluid in fissures

4C. Meconium Aspiration Syndrome (MAS)

• Meconium aspirated into lungs before/during birth → ball-valve obstruction, chemical pneumonitis, surfactant inactivation
• CXR: coarse irregular infiltrates, air trapping, hyperinflation
• Complications: pneumothorax, PPHN
• Management: supportive O2, surfactant (lavage), HFOV, iNO for PPHN

4D. Persistent Pulmonary Hypertension of the Newborn (PPHN)

• Severe hypoxemia (PaO2 <35-45 mmHg in 100% O2)
• Pre-/post-ductal SpO2 gradient ≥7-15 mmHg is significant
• Echocardiogram - structurally normal heart with evidence of shunting

• Supportive: HFOV or conventional ventilation
• Inhaled Nitric Oxide (iNO) - selective pulmonary vasodilator; first-line
• Sildenafil (oral) - second line
• ECMO (extracorporeal membrane oxygenation) for refractory cases

4E. Apnea of Prematurity

• Definition: Cessation of breathing for >20 seconds, or shorter pause with bradycardia or desaturation
• Types:
  • Central: no respiratory effort (most common in preterm)
  • Obstructive: effort but no airflow
  • Mixed: both
• Treatment: Caffeine citrate (first line - reduces apnea frequency, improves neurodevelopmental outcomes); CPAP

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MODULE 5: FLUIDS, ELECTROLYTES, AND NUTRITION

Fluid Requirements by Birth Weight (Harriet Lane Table 18.4)

Glucose Management

• Glucose Infusion Rate (GIR) formula:
  • GIR (mg/kg/min) = 0.167 × [dextrose %] × [infusion rate mL/hr] ÷ weight (kg)
• Preterm neonates require: 5-6 mg/kg/min (target glucose 40-100 mg/dL)
• Term neonates require: 3-5 mg/kg/min

Hypoglycemia

• Definition: Blood glucose <40 mg/dL in term and late preterm infants
• Risk groups: Infants of diabetic mothers (IDM), SGA, LGA, preterm, hypothermia, sepsis
• Treatment: Oral feed first if alert; if persistent or symptomatic → IV dextrose bolus (2 mL/kg of D10W), then continuous GIR

Nutritional Supplements in Preterm Infants

• Iron: 2-6 mg/kg/day elemental iron (start after 10-14 days when on full feeds)
• Vitamin D: 400 IU/day for all infants from birth
• Calcium and phosphorus: Higher requirements in <34 weeks - add breastmilk fortifier or preterm formula

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MODULE 6: NEONATAL JAUNDICE (UNCONJUGATED HYPERBILIRUBINEMIA)

Physiology

1. Higher red cell mass (hematocrit 50-65%)
2. Shorter RBC lifespan (~70 days vs. adult 120 days)
3. Immature hepatic conjugation (low UGT1A1 activity)
4. Increased enterohepatic circulation

Types

Complications

• Acute: hypotonia → hypertonia, retrocollis, seizures
• Chronic: athetoid cerebral palsy, hearing loss, upward gaze palsy (classic triad)

Management

1. Phototherapy: Blue-green light (430-490 nm wavelength) converts unconjugated bilirubin to water-soluble isomers for excretion. Use Bhutani nomogram to determine thresholds.
2. Exchange transfusion: For TSB approaching kernicterus threshold or rising despite intensive phototherapy; removes bilirubin and antibody-coated RBCs
3. IVIG: For immune-mediated hemolytic jaundice (ABO/Rh) to reduce need for exchange transfusion

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MODULE 7: NEONATAL SEPSIS

Classification

Clinical Features (the "sepsis screen")

• Temperature instability (fever or hypothermia)
• CNS: lethargy, irritability, seizures
• Respiratory: apnea, tachypnea, grunting
• GI: poor feeding, vomiting, abdominal distension, diarrhea
• Jaundice (direct hyperbilirubinemia)
• Skin: rash, petechiae
• Hypoglycemia

Diagnosis

• CBC: Neutropenia (<1500/μL) or neutrophilia, elevated I/T ratio (immature/total neutrophil ratio >0.2)
• CRP and procalcitonin (serial monitoring)
• Blood culture: Gold standard - culture before starting antibiotics
• Lumbar puncture: In suspected meningitis
• Urine culture: For late-onset sepsis

GBS Prevention (EOS)

• Universal GBS screening at 35-37 weeks gestation
• Intrapartum antibiotic prophylaxis (IAP) with penicillin/ampicillin for GBS-positive mothers reduces EOS but NOT late-onset GBS disease

Empiric Treatment

• EOS: Ampicillin + Gentamicin (IV)
• LOS/NICU-acquired: Vancomycin + Gentamicin (or cefepime/ceftazidime if Gram-negative coverage needed)
• Meningitis: Ampicillin + Cefotaxime (gentamicin has poor CNS penetration)
• Adjust based on culture/sensitivity results

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MODULE 8: CARDIAC DISEASES IN THE NEWBORN

Patent Ductus Arteriosus (PDA)

• Normal: Ductus closes functionally within 72 hours of birth (triggered by increased O2 + decreased prostaglandins)
• In preterm infants: Delayed closure common due to immature smooth muscle response

• Continuous/systolic murmur at left upper sternal border
• Bounding pulses, wide pulse pressure
• Hyperactive precordium
• CXR: cardiomegaly, increased pulmonary vascular markings
• Echocardiogram: confirms PDA and shunt direction

1. Watchful waiting (many PDAs close spontaneously)
2. Ibuprofen (fewer renal and GI side effects than indomethacin; equally effective)
3. Indomethacin (COX inhibitor; risk of spontaneous intestinal perforation especially with steroids)
4. Acetaminophen (emerging option; similar efficacy to oral ibuprofen)
5. Surgical ligation or transcatheter closure for refractory cases

Cyanotic vs. Acyanotic Heart Disease

• Give 100% O2 for 10 minutes
• If PaO2 rises >150 mmHg → cardiac cause unlikely
• If PaO2 stays <100 mmHg → cyanotic congenital heart disease likely

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MODULE 9: NEUROLOGICAL DISEASES

Hypoxic-Ischemic Encephalopathy (HIE)

1. Gestational age ≥36 weeks
2. One of: Apgar ≤5 at 10 min, continued need for PPV at 10 min, pH <7.0 or base deficit ≥16, or acute perinatal event
3. AND evidence of moderate-to-severe encephalopathy on exam

HIE Severity (Sarnat Staging) - Harriet Lane Table 18.11

• Core temperature 33-34°C for 72 hours
• Must start within 6 hours of birth
• Reduces neuronal death by slowing apoptosis cascades
• Significantly improves neurodevelopmental outcomes

Intraventricular Hemorrhage (IVH)

• 30-40% of infants <1500 g
• 50-60% of infants <1000 g
• 90% occur within first 96 hours of life

Neonatal Seizures

• Clinical manifestations are subtle (neonatal brain is incompletely myelinated)
• Subtle seizures: bicycling, pedaling, eye deviation, lip smacking
• Tonic/clonic seizures also occur
• EEG is the gold standard (many seizures are electrographic only)
• Causes: HIE, metabolic (hypoglycemia, hypocalcemia), infection, stroke, structural
• Treatment: Phenobarbital (first line), levetiracetam (increasingly used), fosphenytoin

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MODULE 10: GASTROINTESTINAL DISEASES

Necrotizing Enterocolitis (NEC)

• Stage I/II: NPO, NG decompression, IV fluids + TPN, antibiotics (ampicillin + gentamicin ± metronidazole)
• Stage III: Surgical consult; peritoneal drain or laparotomy for perforation

Abdominal Wall Defects

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MODULE 11: HEMATOLOGIC DISEASES

Polycythemia

• Definition: Venous hematocrit >65% on two samples
• Causes: Twin-twin transfusion, maternal-fetal transfusion, intrauterine hypoxia, IDM, delayed cord clamping
• Complications: Hyperviscosity → venous thrombosis, CNS injury, hypoglycemia
• Treatment: Partial exchange transfusion for symptomatic polycythemia (target Hct <55%)

Anemia

• Causes: Hemolysis (ABO/Rh incompatibility, G6PD, hereditary spherocytosis), fetomaternal hemorrhage, blood loss
• Physiologic nadir: Term infants Hgb ~10 g/dL at 8-12 weeks; preterm infants earlier and lower (~7 g/dL)

Neonatal Thrombocytopenia

• Most common in neonatal period is neonatal alloimmune thrombocytopenia (NAIT) - maternal antibodies cross placenta and destroy fetal platelets
• High risk of intracranial hemorrhage
• Treatment: IV immunoglobulin, compatible platelet transfusion

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MODULE 12: COMMON NEONATAL CONDITIONS

Neonatal Hypoglycemia (Harriet Lane Table 18.5)

Neonatal Infection - Key Organisms

Birth Trauma

• Caput succedaneum: Edema crossing suture lines; resolves within days
• Cephalohematoma: Subperiosteal hematoma, does NOT cross suture lines; resorbs in weeks-months; risk of jaundice
• Brachial plexus injury:
  • Erb's palsy (C5-C6): arm adducted, internally rotated, "waiter's tip"
  • Klumpke's palsy (C8-T1): claw hand, Horner syndrome

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MODULE 13: PRETERM INFANT - SPECIAL CONSIDERATIONS

Common Complications of Prematurity

Bronchopulmonary Dysplasia (BPD)

• Chronic lung disease of prematurity, diagnosed at 36 weeks corrected gestational age (CGA)
• Definition: Oxygen requirement >21% at 36 weeks CGA or NICU discharge
• Pathophysiology: Arrested alveolar development + inflammation from mechanical ventilation and O2 toxicity
• Management: Diuretics (furosemide), bronchodilators, corticosteroids (postnatal - use judiciously), adequate nutrition

Retinopathy of Prematurity (ROP)

• Abnormal vascular proliferation in immature retina due to hyperoxia exposure
• Screen all infants <30 weeks GA or <1500 g
• Staging: Zones (I-III) and Stages (1-5)
• Treatment: Anti-VEGF (bevacizumab), laser photocoagulation, surgery for Stage 4-5

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MODULE 14: NEONATAL PHARMACOLOGY HIGH-YIELD DRUGS

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QUICK REVIEW: HIGH-YIELD CLINICAL PEARLS

1. APGAR score is NOT used to decide whether to resuscitate - resuscitation starts before the 1-minute score is assigned
2. Jaundice in the first 24 hours = always pathological (hemolytic cause until proven otherwise)
3. GBS EOS can be prevented by IAP but late-onset GBS is not prevented
4. Surfactant deficiency = cause of RDS in preterm; surfactant inactivation = a key mechanism in MAS
5. Therapeutic hypothermia must start within 6 hours of birth; cannot be initiated if infant already >6 hours old
6. IVH occurs in the germinal matrix - the highly vascular but poorly supported periventricular region that involutes by ~34 weeks
7. Pneumatosis intestinalis = pathognomonic for NEC on X-ray
8. Pre/post-ductal SpO2 gradient (right hand vs foot) differentiates PPHN from cardiac disease
9. NEC is uncommon in exclusively breastfed infants - breast milk is protective
10. Caffeine citrate has multiple benefits in preterm: reduces apnea, reduces BPD, improves neurodevelopmental outcome (CAP trial evidence)

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CURRICULUM OUTLINE SUMMARY

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• Delivery room skills (NRP algorithm, ETT sizing, delayed cord clamping)
• Newborn assessment (APGAR, Ballard score, birth weight classifications)
• All major respiratory conditions (RDS, TTN, MAS, PPHN, Apnea of prematurity)
• Fluids/nutrition with actual tables and the GIR formula
• Jaundice - physiology through kernicterus management
• Neonatal sepsis - EOS vs. LOS, organisms, empiric antibiotics
• Cardiac disease - PDA management, cyanotic vs. acyanotic CHD, hyperoxia test
• Neurology - HIE staging, therapeutic hypothermia criteria, IVH grading
• NEC with Bell's staging, abdominal wall defects
• Preterm complications - BPD, ROP, IVH
• High-yield pharmacology table and 10 clinical pearls

• For ward rotations: focus on Modules 1, 2, 6, 7, and 4A-4E
• For OSCE prep: master the APGAR table, Bell's staging, and HIE criteria
• For written exams: the clinical pearls section summarizes the most testable facts

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NEONATOLOGY - COMPLETE DEEP EXPANDED NOTES

For Clinical Medical Students | Source: Harriet Lane Handbook 23rd ed. + Supporting Textbooks

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MODULE 1: NEWBORN RESUSCITATION (NRP - 8th Edition)

1.1 Pre-Delivery Preparation

• Radiant warmer (pre-warmed to 37°C)
• Pre-warmed blankets and a hat
• Bag-mask device (NeoPIP or equivalent) with T-piece resuscitator
• Appropriately sized laryngoscope + ETT ± stylet
• Suction device + bulb syringe
• Pulse oximeter (place on RIGHT hand - pre-ductal)
• Emergency medications: epinephrine 1:10,000
• Vascular access supplies (UVC tray)

• Gestational age <36 weeks
• Multiple gestation
• Meconium-stained fluid
• Fetal bradycardia or non-reassuring tracing
• Known congenital anomaly
• Maternal medications (narcotics, magnesium)

1.2 The NRP Algorithm - Step by Step

Step 1: Initial Assessment (within 30 seconds)

1. Term gestation?
2. Good muscle tone?
3. Breathing or crying?

• All YES → Routine Care: dry, warm, skin-to-skin with mother, ongoing assessment
• Any NO → Resuscitation sequence

Step 2: Warm, Dry, Stimulate, Position, Clear Airway (30-60 seconds)

• Dry vigorously with warm towels
• Stimulate by rubbing back or flicking soles of feet
• Position: sniffing position (slight neck extension)
• Clear airway only if secretions visible (bulb syringe or catheter)
• Do NOT suction routinely - including for meconium-stained fluid

Step 3: Evaluate - Heart Rate + Breathing

• HR >100 + breathing/crying → Labored breathing or cyanosis? → CPAP/O2 → monitor
• HR 60-100 OR not breathing → Start PPV immediately
• HR <60 → PPV + chest compressions

Step 4: Positive Pressure Ventilation (PPV)

• Rate: 40-60 breaths/minute ("Breathe-two-three, Breathe-two-three...")
• Start with 21% O2 (room air) for term infants; 21-30% for preterm
• Increase O2 if no improvement
• Use SpO2 targets (see table below)
• MR SOPA if no chest rise with PPV:
  • M - Mask adjustment
  • R - Reposition airway
  • S - Suction mouth/nose
  • O - Open mouth
  • P - Pressure increase (by 5-10 cmH2O)
  • A - Airway alternative (intubate or LMA)

Target Pre-ductal SpO2 After Birth (Right Hand)

Step 5: Chest Compressions

• Technique: 2-thumb encircling hands (preferred) or 2-finger method
• Depth: One-third of anterior-posterior chest diameter
• Ratio: 3 compressions : 1 ventilation (3:1)
• Rate: 90 compressions + 30 ventilations = 120 events/minute
• Increase O2 to 100% when compressions begin

Step 6: Medications

Step 7: Post-Resuscitation Care

• Maintain temperature (36.5-37.5°C)
• Glucose monitoring (hypoglycemia common post-asphyxia)
• Continuous monitoring: HR, SpO2, BP
• Consider therapeutic hypothermia if criteria met (see Module 9)
• Establish cause of depression

1.3 ETT Size, Depth, and Laryngoscope Blade Selection

ETT Quick Rules:

• ETT size (mm) = gestational age / 10 → i.e., 28 weeks = 2.8 → round to 2.5
• ETT depth (cm from upper lip) = weight (kg) + 6

Laryngoscope Blade:

• Size 0 (straight/Miller): Preterm infants
• Size 1 (straight/Miller): Term infants

1.4 Umbilical Venous Catheter (UVC) - Emergency Access

• Insert just deep enough to obtain blood return during emergent resuscitation
• No measurement or imaging required before emergent use
• UVC is the primary route for epinephrine and volume in the delivery room

1.5 Cord Clamping

Delayed Cord Clamping (DCC) - 30-60 seconds:

Absolute Contraindications to DCC:

Cord Milking (squeezing):

• CONTRAINDICATED in <28 weeks (increased IVH risk)
• Insufficient evidence for 28-32 weeks
• May be used for term infants if DCC not possible

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MODULE 2: ROUTINE NEWBORN CARE OF THE TERM INFANT

2.1 Immediate Post-Delivery Care

In the First Hour ("Golden Hour"):

1. Temperature: Skin-to-skin contact maintains temperature (or radiant warmer). Target axillary temp 36.5-37.5°C.
2. Feeding: Initiate breastfeeding within first hour. Breastfed infants feed 8-12 times per 24 hours.
3. Vitamin K 1 mg IM - into vastus lateralis. Prevents Vitamin K Deficiency Bleeding (VKDB)/Hemorrhagic Disease of the Newborn (HDN). Oral Vitamin K is NOT recommended (inadequate levels, compliance issues).
4. Erythromycin 0.5% eye ointment - prophylaxis against gonococcal ophthalmia neonatorum. Apply to both eyes within 1 hour.
5. Hepatitis B vaccine (1st dose) - give in delivery room if mother HBsAg-negative and infant is medically stable. If mother HBsAg-positive → give HBV vaccine + HBIG within 12 hours.
6. Umbilical cord care - keep dry and clean. Do not apply antiseptics or alcohol (delays cord separation).

2.2 Newborn Screening

Metabolic Screening (State-mandated, varies by state):

• Endocrine: Congenital hypothyroidism, congenital adrenal hyperplasia
• Amino acid disorders: PKU (phenylketonuria), maple syrup urine disease, homocystinuria, tyrosinemia
• Fatty acid oxidation: MCAD deficiency, LCHAD
• Organic acidemias: Propionic acidemia, methylmalonic acidemia, isovaleric acidemia
• Hemoglobin disorders: Sickle cell disease, hemoglobin variants
• Other: Cystic fibrosis, severe combined immunodeficiency (SCID), spinal muscular atrophy (SMA)
• Timing: 24-48 hours of life (ideally after first feed to allow phenylalanine accumulation for PKU detection)

Critical Congenital Heart Disease (CCHD) Pulse Oximetry Screening:

• Screen at 24-48 hours of life (or just before discharge if <24 hours)
• Measure SpO2 in right hand (pre-ductal) AND either foot (post-ductal)
• Fail criteria (screen positive): SpO2 <90% in any reading; OR SpO2 <95% in both right hand and foot on 3 separate readings (1 hour apart); OR difference >3% between right hand and foot on 3 separate readings

Hearing Screen:

• All newborns before discharge
• Automated otoacoustic emissions (AOAE) or automated auditory brainstem response (AABR)
• Refer for full audiologic assessment if fail bilateral

2.3 Common Normal Newborn Findings (vs. Pathological)

2.4 Breastfeeding Support

• 6+ wet diapers/day by day 4-5
• Regaining birth weight by 10-14 days
• Audible swallowing during feeds
• Satisfied after feeds

• Poor latch → cracked nipples, inadequate intake
• Engorgement → warm compress before, cold after feeds
• Mastitis → antibiotics (dicloxacillin/cephalexin), continue breastfeeding

• HIV-positive mother in developed countries
• Active tuberculosis (untreated)
• Active herpes lesions on the breast
• Maternal chemotherapy/radiation
• Galactosemia in infant

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MODULE 3: NEWBORN ASSESSMENT

3.1 APGAR Score - Deep Dive

Scoring Interpretation:

• 7-10: Normal. Good adaptation.
• 4-6: Moderate depression. Stimulation and supplemental O2 usually sufficient.
• 0-3: Severe depression. Immediate resuscitation required.
• Repeat at 5-minute intervals until score ≥7.

Prognostic Value:

• 5-minute score <7 is associated with increased risk of adverse neurodevelopmental outcomes
• Persistent score of 0 at 10 minutes is associated with mortality and severe disability (consider discontinuing resuscitation)
• Important: Low APGAR alone does NOT diagnose birth asphyxia or HIE. Requires ABG evidence.

3.2 Gestational Age Assessment

Obstetric Dating (most accurate):

• First-trimester ultrasound (crown-rump length)
• Last menstrual period

New Ballard Score (when obstetric dating unavailable):

3.3 Gestational Age Classification

3.4 Neonatal Reflexes

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MODULE 4: RESPIRATORY DISEASES OF THE NEWBORN

4A. Respiratory Distress Syndrome (RDS) / Hyaline Membrane Disease (HMD)

Pathophysiology - Full Chain:

1. Prematurity → immature type II pneumocytes → insufficient surfactant production
2. Surfactant deficit → increased surface tension at air-liquid interface
3. Increased surface tension → alveolar collapse at end-expiration (atelectasis)
4. Atelectasis → V/Q mismatch + intrapulmonary shunting → hypoxemia
5. Hypoxemia + acidosis → pulmonary vasoconstriction → worsens PPHN component
6. Protein-rich fluid leaks into alveoli → forms hyaline membranes (eosinophilic on histology)
7. Decreased lung compliance → increased work of breathing

Surfactant Composition:

• 70-80% phospholipids (mainly dipalmitoylphosphatidylcholine/DPPC)
• 5-10% neutral lipids
• 10% surfactant proteins (SP-A, SP-B, SP-C, SP-D)
• SP-B and SP-C are essential for surface tension reduction
• SP-A and SP-D are involved in immune defense

Clinical Presentation Timeline:

• Birth → 4-6 hours: Symptoms begin (tachypnea >60/min, grunting, nasal flaring, intercostal/subcostal retractions, cyanosis)
• Grunting mechanism: Partial glottis closure during expiration to maintain positive end-expiratory pressure → self-PEEP
• 6-72 hours: Worsening (peak at 48-72 hours)
• 72-96 hours: Improvement (accompanied by brisk diuresis)
• Recovery is marked by diuresis because fluid mobilizes as lung compliance improves

CXR Findings:

• Diffuse, bilateral, symmetric ground-glass opacity (from microatelectasis)
• Low lung volumes (hypoinflation) - ribs appear short
• Air bronchograms (air-filled bronchi visible against collapsed lung parenchyma)
• In severe cases: complete "white-out" of lung fields

RDS Incidence (inversely related to gestational age):

Antenatal Corticosteroids (ACS):

• Betamethasone 12 mg IM x2 doses, 24 hours apart (preferred; less neonatal side effects)
• OR Dexamethasone 6 mg IM x4 doses, 12 hours apart
• Give to ALL women at risk of preterm birth <34 weeks
• Maximally effective if delivered 24 hours - 7 days after 1st dose
• Benefits: Reduces RDS severity, IVH, NEC, overall mortality
• Repeat course: Only if prior course >14 days ago AND <34 weeks
• Use at 34-36 weeks is controversial (insufficient evidence for long-term effects)

Surfactant Therapy:

• Mechanism: Exogenous surfactant replaces deficient endogenous surfactant → reduces surface tension → recruits alveoli → improves compliance and oxygenation
• Types:
  • Natural (animal-derived): Poractant alfa (Curosurf), Beractant (Survanta), Calfactant (Infasurf)
  • Synthetic: Lucinactant (Surfaxin), Poractant alfa recombinant
  • Natural > synthetic (better outcomes in RCTs)
• Timing: Prophylactic (at birth, before symptoms) vs. rescue (after diagnosis) - rescue now standard with improved antenatal steroid use
• Route: Via ETT, either direct intratracheal instillation or LISA (Less Invasive Surfactant Administration) - a thin catheter while infant breathes on CPAP
• Dose: Poractant alfa 200 mg/kg for first dose, 100 mg/kg for subsequent doses
• Repeat dosing: If FiO2 >0.30-0.40 within 6-12 hours (up to 2-3 total doses)

Ventilatory Support:

1. CPAP (Continuous Positive Airway Pressure): First-line for mild-moderate RDS; prevents atelectasis; target 4-8 cmH2O
2. High-Flow Nasal Cannula (HFNC): Alternative to CPAP for milder disease
3. Intubation + mechanical ventilation: Severe RDS, apnea, or failure of non-invasive support
4. HFOV (High Frequency Oscillatory Ventilation): For air-leak syndrome or failure of conventional ventilation
5. Target SpO2 91-95% in preterm infants (avoid hyperoxia - causes ROP, BPD)

Complications of RDS:

• Air leak: Pneumothorax, pneumomediastinum, pulmonary interstitial emphysema (PIE)
• BPD (chronic lung disease of prematurity)
• IVH (from hypoxia and hypotension)
• PDA (common in preterm with RDS)
• NEC

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4B. Transient Tachypnea of the Newborn (TTN)

Pathophysiology:

• During vaginal delivery, thoracic squeeze expels ~30 mL of fetal lung fluid
• Cesarean section (especially without labor) → no thoracic squeeze → fluid retained
• Immature epithelial Na+ channels (ENaC) fail to reabsorb fluid normally
• Fluid in alveoli/interstitium → reduced compliance → tachypnea

Risk Factors:

• C-section without labor (biggest risk)
• Male sex
• Macrosomia
• Lower gestational age (late preterm)
• Maternal diabetes, asthma, maternal smoking

Clinical Features:

• Symptoms within first 6 hours of birth
• Tachypnea (>60/min, often 80-100/min)
• Mild retractions, grunting, nasal flaring
• Cyanosis is rare (distinguishes from RDS)
• Resolves within 12-72 hours (usually by 72 hours)

CXR:

• Hyperinflation (retained fluid increases lung volumes - opposite of RDS)
• Perihilar streaking (fluid in lymphatics)
• Fluid in interlobar fissures
• Mild cardiomegaly possible

Management:

• Supportive only - this is self-resolving
• NPO with IV dextrose if tachypnea persists and aspiration risk is high
• Supplemental O2 and/or CPAP as needed
• Monitor for resolution; rule out other diagnoses if not resolving by 72 hours

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4C. Meconium Aspiration Syndrome (MAS)

Pathophysiology:

• Meconium passed in utero (sign of fetal stress, hypoxia, or post-term) mixes with amniotic fluid
• Aspirated during gasping movements in utero or at first breath
• Three mechanisms of injury:
  1. Mechanical obstruction - thick meconium plugs airways → ball-valve effect → hyperinflation + atelectasis
  2. Chemical pneumonitis - bile salts in meconium irritate airways → inflammation → edema
  3. Surfactant inactivation - meconium inactivates surfactant → atelectasis + V/Q mismatch

Clinical Features:

• Stained amniotic fluid (yellow-green meconium)
• Infant may be post-term, SGA, or distressed
• Respiratory distress within hours of birth
• Barrel chest (from air-trapping)
• Cyanosis, grunting, tachypnea

CXR:

• Coarse, irregular, patchy infiltrates (mixed atelectasis and hyperinflation)
• Hyperinflation (barrel chest on film)
• Air leaks in 10-20% (pneumothorax from ball-valve effect)

Complications:

• Pneumothorax/pneumomediastinum
• PPHN (most serious - from hypoxic pulmonary vasoconstriction)
• Chemical pneumonitis
• Bacterial superinfection

Management:

• Delivery room: Do NOT routinely suction even if non-vigorous (NRP 8th ed. removed this recommendation). Provide PPV if needed.
• NICU:
  • Supplemental O2, CPAP, or mechanical ventilation
  • Surfactant (lavage or bolus - inactivated surfactant replaced)
  • Antibiotics (secondary infection possible)
  • Treat PPHN with iNO if develops
  • ECMO for severe refractory cases

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4D. Persistent Pulmonary Hypertension of the Newborn (PPHN)

Fetal vs. Neonatal Circulation:

• In utero: High PVR (lungs not needed, fluid-filled) → blood shunts R→L through foramen ovale and ductus arteriosus → bypasses lungs
• At birth: Lungs inflate → O2 dilates pulmonary vessels → PVR drops dramatically → L→R flow now through pulmonary circulation

Causes:

1. Idiopathic PPHN (pulmonary vasculature maladaption/remodeling)
2. Secondary PPHN from:
   • Meconium aspiration (most common cause)
   • Pneumonia/sepsis
   • Congenital diaphragmatic hernia (CDH) - pulmonary hypoplasia
   • RDS
   • Polycythemia
   • Hypoxia/acidosis from any cause

Clinical Features:

• Presents within 12-24 hours of birth
• Severe hypoxemia disproportionate to radiologic changes (key feature)
• PaO2 <35-45 mmHg in 100% O2 (fails hyperoxia test)
• Pre-post ductal gradient:
  • Pre-ductal (right hand SpO2) MINUS post-ductal (foot SpO2) ≥7-15 mmHg = significant
  • This means blood is shunting R→L through the ductus (post-ductal blood is less oxygenated)
• Loud S2 (elevated RV pressure)
• Structurally normal heart on echo (distinguishes from cyanotic CHD)

Hyperoxia Test:

• Place in 100% O2 for 10 minutes
• PaO2 rises to >150 mmHg → cardiac cause unlikely (lung disease)
• PaO2 stays <100 mmHg → cyanotic CHD or PPHN

Management of PPHN:

1. Optimize oxygenation: Supplemental O2 (pulmonary vasodilator)
2. Minimize stimulation: Minimal handling, sedation, paralysis if intubated (noxious stimuli cause acute pulmonary vasoconstriction)
3. Avoid hypocarbia: PCO2 <30 mmHg → myocardial ischemia + decreased cerebral blood flow; target PCO2 40-50 mmHg
4. Maintain systemic BP: Volume expanders (normal saline 10 mL/kg), inotropes (dopamine, dobutamine) to keep systemic BP > pulmonary arterial pressure
5. Pulmonary vasodilators:
   • Inhaled Nitric Oxide (iNO): First-line; dose 20 ppm (10 ppm for preterm); reduces PVR WITHOUT reducing systemic BP (selective pulmonary vasodilator); watch for methemoglobinemia (reduce if >4%), NO2 toxicity
   • Sildenafil (oral): PDE-5 inhibitor → cGMP → pulmonary vasodilation; second-line when iNO unavailable or inadequate
   • Prostacyclin analogs (epoprostenol): IV or inhaled; third-line
6. ECMO (Extracorporeal Membrane Oxygenation): Last resort; criteria: oxygenation index (OI) >40 for >3 hours OR A-aO2 gradient ≥610 for 8 hours; infant must be >2000 g and >34 weeks

Oxygenation Index (OI):

• OI >25 = severe respiratory failure
• OI >40 = consider ECMO

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4E. Apnea of Prematurity

Definition:

Types:

Pathophysiology:

• Immature brainstem respiratory center (nucleus tractus solitarius)
• Depressed hypoxic ventilatory response - preterm paradoxically decrease breathing in response to hypoxia (opposite of adults)
• Elevated inhibitory neurotransmitters (adenosine)

Differential Diagnosis of Neonatal Apnea (must exclude before diagnosing "apnea of prematurity"):

• Infection (sepsis, meningitis)
• Metabolic: hypoglycemia, hypocalcemia, hyponatremia
• Respiratory: RDS, pneumonia, airway obstruction
• Neurologic: IVH, seizures, HIE
• Cardiac: PDA, arrhythmia
• Anemia
• Temperature instability (hypothermia or hyperthermia)
• Gastroesophageal reflux (GER) - controversial causal link

Management:

1. Caffeine citrate (methylxanthine - first line):
   • Loading dose: 20 mg/kg IV/PO
   • Maintenance: 5-10 mg/kg/day
   • Mechanism: Adenosine receptor antagonist → stimulates respiratory center, increases chemoreceptor sensitivity to CO2, improves diaphragmatic contractility
   • CAP Trial evidence: Caffeine reduces apnea, reduces BPD, reduces need for PDA treatment, and improves neurodevelopmental outcomes at 18-21 months and at 11 years
   • Wean when infant is 34-35 weeks corrected gestational age
2. CPAP/HFNC: Provides positive pressure → splints upper airway → reduces obstructive component
3. Stimulation: Tactile stimulation for individual episode
4. Doxapram: Second line when caffeine insufficient (respiratory stimulant)
5. Intubation/mechanical ventilation: For very frequent or severe refractory apnea

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MODULE 5: FLUIDS, ELECTROLYTES, AND NUTRITION

5.1 Neonatal Fluid Physiology

Why Neonates Have Special Fluid Needs:

• High body water content (85% of body weight at 24 weeks → 75% at term → 60% in adults)
• Large surface area to body weight ratio → higher insensible losses
• Insensible water loss (IWL) = losses through skin (60%) + lungs (40%)
• IWL is dramatically higher in preterm infants due to:
  • Immature skin (no keratin barrier in <30 weeks)
  • High respiratory rate
  • Radiant warmers and phototherapy lamps further increase IWL

Maintenance Fluid Requirements (Harriet Lane Table 18.4):

• Physiologic postnatal diuresis occurs on Days 2-4 (reabsorption of fetal lung fluid + normal weight loss)
• Expected weight loss of 7-10% in first week (normal)

Factors That Increase Fluid Requirements:

• Phototherapy (+20-30 mL/kg/day)
• Radiant warmer vs. incubator (radiant warmer increases IWL by 2-3x)
• Fever
• Diarrhea
• Surgical drains, ostomies

Electrolyte Requirements (Harriet Lane Table 18.6):

5.2 Glucose Management

Glucose Infusion Rate (GIR):

• D10W at 60 mL/kg/day in a 1 kg infant: 0.167 × 10 × 2.5 ÷ 1 = 4.2 mg/kg/min
• Term neonate requirement: 3-5 mg/kg/min
• Preterm neonate requirement: 5-6 mg/kg/min (target glucose 40-100 mg/dL)

Hypoglycemia Management:

• Causes: Excess glucose delivery, sepsis, hypoxia, hyperosmolar formula, neonatal diabetes, medications (steroids, dopamine)
• Management: Decrease GIR; monitor glucosuria; insulin infusion for persistent hyperglycemia

5.3 Nutrition

Caloric Requirements:

• Term infant: 100-120 kcal/kg/day for growth
• Preterm infant: 110-135 kcal/kg/day (higher needs due to higher metabolic rate and catch-up growth)
• 80 kcal/kg/day = maintenance only (no growth)

Enteral Nutrition:

• Human milk is gold standard for all infants, especially preterm
• Reduces NEC incidence, improves neurodevelopmental outcomes, provides immunoprotective factors
• Human milk fortifier: Added to expressed breast milk for infants <34 weeks (breast milk alone insufficient for preterm protein/mineral needs)
• Donor breast milk (pasteurized): Used when mother's own milk unavailable
• Preterm formula (24-30 kcal/oz): Used when breast milk unavailable

Parenteral Nutrition (PN) for Preterm Infants:

• Amino acids: Start 2-3 g/kg/day, advance to 3.5-4 g/kg/day
• Lipids (intralipid): Start 1-2 g/kg/day, advance to 3-4 g/kg/day
• Dextrose: Titrate to maintain GIR 5-6 mg/kg/min
• Monitor triglycerides, liver function, glucose

Mineral and Vitamin Supplementation:

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MODULE 6: NEONATAL JAUNDICE

6.1 Bilirubin Metabolism in Neonates

Bilirubin Production Pathway:

Why Neonates Get Jaundiced:

1. High bilirubin production: Hematocrit 50-65%; fetal Hgb (HbF) replaced by adult Hgb → massive RBC breakdown; neonatal RBC lifespan only 70-90 days (vs. adult 120 days)
2. Low hepatic clearance: Immature UGT1A1 (glucuronosyltransferase) - only 1% of adult activity at birth; low hepatic uptake protein (ligandin)
3. Increased enterohepatic circulation: β-glucuronidase in neonatal gut deconjugates bilirubin → reabsorption; sterile gut (no bacteria to convert to urobilinogen)

6.2 Classification of Neonatal Jaundice

Physiologic vs. Pathologic:

Types in Detail:

ABO Incompatibility:

• Mother type O; baby type A or B
• Anti-A or Anti-B IgG crosses placenta
• Usually mild hemolysis (antibodies less potent than anti-D)
• Positive direct Coombs (DAT) in baby - not always strongly positive

Rh Incompatibility (Erythroblastosis Fetalis):

• Rh-negative mother sensitized to Rh-positive fetal blood
• Anti-D IgG crosses placenta → massive hemolysis in fetus/neonate
• Hydrops fetalis in severe cases (massive hemolysis → fetal anemia → heart failure → generalized edema)
• Prevention: Rh immunoglobulin (RhIG/RhoGAM) given to Rh-negative mothers at 28 weeks and within 72 hours after delivery of Rh-positive baby

6.3 Kernicterus (Bilirubin Encephalopathy)

Mechanism:

• Unconjugated bilirubin crosses the blood-brain barrier when:
  • TSB is very high
  • Albumin is saturated (binding capacity exceeded)
  • Conditions reduce albumin-bilirubin binding: acidosis, hypoxia, hypothermia, certain drugs (sulfonamides, ceftriaxone, furosemide)

Preferred sites of deposition:

• Basal ganglia (especially globus pallidus)
• Hippocampus
• Subthalamic nuclei
• Brainstem nuclei (cranial nerve nuclei, inferior colliculus)

Clinical Phases:

• Phase 1 (early): Hypotonia, poor suck, lethargy, shrill cry
• Phase 2 (middle): Hypertonia, retrocollis (neck hyperextension), opisthotonus, fever
• Phase 3 (late): Hypotonia returns; may appear to improve

1. Athetoid/choreoathetoid cerebral palsy (basal ganglia damage)
2. Sensorineural hearing loss (auditory pathway damage)
3. Upward gaze palsy (Parinaud syndrome - midbrain compression) Plus: dental dysplasia, intellectual disability

6.4 Management of Hyperbilirubinemia

Bhutani Nomogram:

• High risk zone (>75th percentile at age)
• High intermediate risk zone
• Low intermediate risk zone
• Low risk zone (<40th percentile)

• Isoimmune hemolytic disease
• G6PD deficiency
• Birth asphyxia
• Significant lethargy
• Temperature instability
• Sepsis, acidosis
• Albumin <3.0 g/dL

Phototherapy:

• Lumirubin (major product) - water-soluble, excreted in bile and urine without needing conjugation
• Photoisomers - less stable

• Conventional (overhead fluorescent/LED lamps)
• Intensive phototherapy: Multiple light sources, fiber-optic biliblanket underneath
• Maximum skin surface exposure is key (remove clothing, diaper for maximum exposure)

• "Bronze baby syndrome" - gray-brown discoloration (in infants with cholestasis - conjugated bilirubin absorbs light → toxic photoproducts)
• Loose stools/diarrhea
• Hyperthermia
• Dehydration (increased IWL)
• Retinal damage (cover eyes!)

Exchange Transfusion:

• Double volume exchange: 160 mL/kg (term) or 200 mL/kg (preterm) of blood
• Replaces ~85% of infant's blood volume
• Route: Blood withdrawn via UAC; equal volume infused via UVC; in 15 mL aliquots
• Pre-exchange blood: Send CBC, reticulocyte count, peripheral smear, bilirubin, Ca2+, glucose, blood type, Coombs - these are useless post-exchange

IVIG:

• For isoimmune hemolytic disease (ABO or Rh)
• Dose: 0.5-1 g/kg IV over 2 hours
• Mechanism: Blocks Fc receptors on reticuloendothelial cells → reduces RBC destruction
• Reduces need for exchange transfusion

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MODULE 7: NEONATAL SEPSIS

7.1 Overview and Classification

Early-Onset Sepsis (EOS): 0-6 days of life

• Primary source: Vertical transmission from colonized maternal genital tract
• Typically presents as respiratory distress or generalized illness within hours of birth
• Organisms:
  • Group B Streptococcus (GBS/S. agalactiae): #1 cause
  • E. coli: #2 cause, especially in preterm; K1 capsular antigen associated with meningitis
  • Listeria monocytogenes: From contaminated food (deli meats, soft cheese); granulomatosis infantiseptica
  • Enterococcus, Haemophilus influenzae, Klebsiella

Late-Onset Sepsis (LOS): Day 7-89+ (some define 8-28 days for LOS)

• Primary source: Environmental/nosocomial (NICU) or community
• More insidious onset ("rule out sepsis" work-up)
• Organisms:
  • Coagulase-negative Staphylococci (CoNS) / S. epidermidis: Most common in NICU; associated with indwelling lines
  • S. aureus (including MRSA)
  • GBS: Late-onset GBS (not prevented by IAP)
  • Gram-negative bacilli: E. coli, Klebsiella, Enterobacter, Pseudomonas
  • Candida species: C. albicans, C. parapsilosis; high risk in VLBW infants on broad-spectrum antibiotics, TPN, indwelling catheters

7.2 Risk Factors

For EOS:

• GBS-positive mother without IAP
• Preterm delivery (<37 weeks)
• Prolonged rupture of membranes (PROM) >18 hours
• Intrapartum fever (maternal chorioamnionitis)
• Previous sibling with invasive GBS disease
• GBS bacteriuria in current pregnancy

For LOS:

• Prematurity/VLBW (immature immune system)
• Prolonged NICU stay
• Indwelling central lines (UAC, PICC, UVC)
• Mechanical ventilation (ETT bypasses mucociliary defenses)
• TPN (medium for bacterial growth)
• Broad-spectrum antibiotic use (Candida overgrowth)
• Prolonged NPO (disrupted gut microbiome)

7.3 Clinical Features

7.4 Diagnosis

Blood Work:

Lumbar Puncture (LP):

• Any suspected EOS in term infants
• Any confirmed bacteremia (blood culture positive)
• Clinical deterioration despite antibiotics
• Any neonatal seizures

Urine Culture:

• Obtain by catheterization or suprapubic aspiration (NOT bag specimen)
• Indicated for LOS work-up and any infant >7 days old

Surface cultures (skin, ear, umbilicus): Low utility, not recommended routinely

7.5 GBS Prevention Program

• GBS-positive → Intrapartum Antibiotic Prophylaxis (IAP)
• IAP agents:
  • Penicillin G (preferred, narrow spectrum)
  • Ampicillin (alternative)
  • Cefazolin (penicillin-allergic, low risk)
  • Clindamycin (resistant if susceptibility unknown → use vancomycin)

• Previous infant with invasive GBS disease
• GBS bacteriuria in current pregnancy
• Unknown GBS status + delivery <37 weeks, PROM >18h, or intrapartum fever ≥38°C

7.6 Empiric Antibiotic Treatment

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MODULE 8: CARDIAC DISEASES IN THE NEWBORN

8.1 Patent Ductus Arteriosus (PDA)

Fetal Ductus Physiology:

• In fetus: Ductus arteriosus connects pulmonary artery (PA) to descending aorta
• Maintained patent by: High prostaglandin E2 (PGE2), low O2 tension
• At birth: Lung expansion + O2 → inhibit prostaglandins → ductal smooth muscle contracts → functional closure within 72 hours
• Anatomic closure (fibrosis to ligamentum arteriosum): 1-3 months

PDA in Preterm Infants:

• Smooth muscle response to O2 is immature → duct fails to close
• High PGE2 levels in preterm due to immature prostaglandin metabolism
• Incidence: 45-70% of infants <28 weeks; decreases with increasing GA

Hemodynamic Effects:

• Blood flows Aorta → PA → pulmonary circulation (overcirculation)
• Pulmonary edema → respiratory distress, increased FiO2 requirement
• Pulmonary steal → decreased diastolic flow in aorta → intestinal ischemia (NEC risk), renal hypoperfusion

• Bounding pulses (wide pulse pressure = high systolic from LA/LV overflow, low diastolic from run-off into PA)
• Hyperactive precordium
• Widened pulse pressure (diastolic BP low)
• Systolic or continuous murmur at left upper sternal border / infraclavicular area
• Increased FiO2 requirement
• Worsening respiratory status

Echocardiogram (gold standard):

• Demonstrates ductus arteriosus
• Measures: size of duct, direction of shunt, LA:Ao ratio (>1.4 suggests significant left heart overcirculation), LV function

Management Controversy:

1. Conservative/Watchful waiting: Many centers now favor expectant management; restrict fluids, maintain hematocrit >35%
2. Indomethacin (COX inhibitor): Reduces PGE2 → ductal closure; side effects: renal (decreased GFR, oliguria), GI bleeding, spontaneous intestinal perforation (SIP), thrombocytopenia
3. Ibuprofen (oral or IV): Equally effective as indomethacin but fewer renal and GI side effects; preferred when available
4. Acetaminophen (oral or IV): Emerging evidence suggests similar efficacy to oral ibuprofen without platelet effects; mechanism unclear (possibly inhibits PG synthetase differently)
5. Surgical ligation: For medically refractory PDA with significant hemodynamic compromise
6. Transcatheter device closure: Now available even for VLBW infants at some centers

8.2 Congenital Heart Disease (CHD) - Overview

Incidence:

• 8 per 1000 live births (most common congenital anomaly)
• 1/3 are critical (require intervention in first year)

Acyanotic vs. Cyanotic:

"5 Ts of Cyanotic CHD":

Critical Management Principles:

• Indication: Any ductal-dependent circulation (TGA, pulmonary atresia, critical PS, severe CoA, HLHS)
• Dose: 0.05-0.1 mcg/kg/min IV infusion
• Side effects: Apnea, fever, hypotension, jitteriness - have intubation equipment ready
• Mechanism: Maintains ductal patency by stimulating PGE2 receptors in ductal smooth muscle

Hyperoxia Test (Nitrogen Washout Test):

1. Place in 100% O2 × 10 minutes
2. Measure PaO2 (ABG from right hand = pre-ductal)
3. PaO2 >150-200 mmHg = pulmonary cause likely (RDS, pneumonia, PPHN - responds to O2)
4. PaO2 <100 mmHg = cyanotic CHD or PPHN (fixed R→L shunt not overcome by O2)

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MODULE 9: NEUROLOGICAL DISEASES OF THE NEWBORN

9.1 Hypoxic-Ischemic Encephalopathy (HIE)

Mechanism of Brain Injury (2-phase):

• O2 deprivation → anaerobic metabolism → lactic acidosis → ATP depletion
• Cell membranes fail → Na+/K+ ATPase fails → cellular swelling
• Glutamate release → excitotoxicity → NMDA receptor activation → Ca2+ influx
• Immediate neuronal death (necrosis)

• Reperfusion injury: O2 restoration + mitochondrial dysfunction → reactive oxygen species (ROS)
• Continued Ca2+ influx → mitochondrial dysfunction → cytochrome c release → apoptosis
• Inflammation, cytokine release
• This is the therapeutic window - target for cooling!

• Reduces cerebral metabolic rate (~5% per 1°C decrease)
• Reduces excitatory amino acid release
• Inhibits apoptosis cascades
• Reduces inflammation
• Reduces ROS production

Clinical Criteria for Therapeutic Hypothermia (TH):

• Cord gas or blood gas in first hour with pH <7.0 OR base deficit ≥16
• If pH 7.01-7.15 or base deficit 10-15.9 → need additional criteria:
  • Acute perinatal event (abruption, cord prolapse, uterine rupture, shoulder dystocia)
  • 10-minute APGAR ≤5
  • Need for assisted ventilation at birth ≥10 minutes

• Lethargy or coma
• Seizures
• Abnormal tone (hypotonia or hypertonia)
• Abnormal brainstem reflexes

Sarnat Staging (modified - Harriet Lane Table 18.11):

Therapeutic Hypothermia Protocol:

• Target temperature: 33-34°C core (rectal or esophageal)
• Duration: 72 hours
• Must start within 6 hours of birth (beyond 6 hours: uncertain benefit)
• Method: Whole-body cooling blanket (servo-controlled) preferred
• Monitoring during cooling: Continuous EEG, hourly temperatures, glucose (hypoglycemia common), electrolytes, coagulation, cardiovascular monitoring
• Complications of cooling: Bradycardia (expected), coagulopathy, pulmonary hypertension, feeding intolerance, metabolic acidosis
• Rewarming: 0.2-0.5°C per hour over 6-12 hours (do NOT rewarm rapidly → risks rebound seizures)

Adjunctive Therapies (emerging evidence):

• Erythropoietin (EPO)
• Melatonin
• Xenon gas (hyperpolarizes NMDA receptors)
• Stem cell therapy (investigational)

9.2 Intraventricular Hemorrhage (IVH)

Anatomy of the Germinal Matrix:

• Highly cellular, vascular subependymal region
• Source of neuronal and glial precursors in fetal brain
• Involutes by 34-36 weeks gestation
• Poorly supported thin-walled capillaries → vulnerable to pressure fluctuations

Mechanism of IVH:

• Fluctuating cerebral blood flow (CBF) → pressure overload on germinal matrix capillaries → rupture → blood fills lateral ventricles
• Triggers for CBF fluctuation:
  • Hypotension or hypertension
  • Rapid volume boluses
  • Vigorous suctioning
  • Head turning (compromises jugular venous drainage)
  • High ventilator pressures
  • Pneumothorax (acute)
  • Seizures

Incidence:

• 30-40% of infants <1500 g
• 50-60% of infants <1000 g
• 50% of IVHs occur within first 24 hours of life
• 90% occur within first 96 hours
• Rare after 7-10 days of life

Grading (Papile Classification - by head ultrasound):

Prevention:

• Antenatal corticosteroids (most evidence-based prevention)
• Delayed cord clamping (reduces need for volume resuscitation)
• Avoid rapid fluid boluses
• Maintain head in midline position
• Minimize blood pressure swings
• Prophylactic indomethacin (reduces IVH incidence but does not improve neurodevelopmental outcomes - not routinely recommended)
• Gentle ventilation strategies
• Minimize handling, noxious stimuli

Management:

• Serial head ultrasounds (weekly × 4 weeks, then as clinically indicated)
• No medical treatment to stop IVH or reverse it
• Treat complications:
  • Post-hemorrhagic hydrocephalus (PHH): Serial LPs or ventricular access device (reservoir) → VP shunt if persistent
  • Seizures: Phenobarbital, levetiracetam
  • Anemia from blood loss: Transfusion

Long-term Outcomes:

• Grade I-II: Neurodevelopmental outcome generally favorable
• Grade III: 25-50% risk of motor/cognitive disability
• Grade IV: 50-80% risk of severe disability; significant mortality

9.3 Periventricular Leukomalacia (PVL)

• White matter injury of prematurity (different from IVH)
• Cystic PVL: Most severe form - cysts in periventricular white matter on ultrasound
• Diffuse PVL: More common, white matter signal abnormality on MRI
• Mechanism: Hypoxia-ischemia or infection damages pre-oligodendrocytes → impaired myelination → CP, cognitive impairment
• Association: Spastic diplegia (bilateral leg spasticity - from damage to descending corticospinal tracts serving legs running near ventricles)

9.4 Neonatal Seizures

Why Neonatal Seizures Are Unique:

• Incomplete myelination and immature inhibitory pathways → seizures manifest differently
• GABA is excitatory in neonates (immature chloride transporters)
• High rate of electrographic-only (subclinical) seizures - clinical exam alone misses >50% of seizures in monitored infants

Clinical Manifestations:

Etiology by Timing:

Diagnostic Work-up:

1. Blood glucose (immediate)
2. Electrolytes: Na, Ca, Mg, phosphate
3. Blood gas (pH, bicarbonate)
4. CBC, blood culture (sepsis evaluation)
5. LP (meningitis)
6. EEG (most important - confirms and monitors seizures)
7. Brain imaging: Head ultrasound (IVH, PVL); MRI (HIE pattern, stroke, structural)
8. Metabolic screen (organic acids, amino acids, ammonia)

Treatment:

• Loading dose: 20 mg/kg IV (can give additional 10-20 mg/kg if seizures continue)
• Maintenance: 3-5 mg/kg/day divided Q12-24h
• Monitor for respiratory depression and sedation

• Loading: 40-60 mg/kg IV
• Better side effect profile than phenobarbital
• NEOLEV2 trial: Similar efficacy to phenobarbital

• Loading: 15-20 mg PE/kg IV
• Side effects: Arrhythmia, hypotension

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MODULE 10: GASTROINTESTINAL DISEASES

10.1 Necrotizing Enterocolitis (NEC)

Pathophysiology Triad:

1. Intestinal immaturity - immature mucosal barrier, reduced mucus production, immature immune defenses (reduced secretory IgA, TLR4 overexpression)
2. Microbial colonization - dysbiotic gut flora, bacterial overgrowth after enteral feeding begins
3. Bowel ischemia - mesenteric vasoconstriction, redistribution of blood flow away from gut

Risk Factors:

• Prematurity (greatest risk - 90% of NEC cases are preterm)
• RDS, HIE, polycythemia-hyperviscosity
• Umbilical catheterization
• Exchange transfusion
• PDA with significant hemodynamic compromise
• Cyanotic CHD (particularly associated with certain lesions requiring PGE1)
• Enteral feeding (particularly rapid advancement)
• Intrauterine cocaine exposure

Bell's Staging (modified - Harriet Lane eTable 18.1):

Key Radiographic Signs:

• Pneumatosis intestinalis: Gas in bowel wall (pathognomonic for NEC) - bubbles or linear lucencies in bowel wall
• Portal venous gas: Gas tracking toward liver along portal veins (indicates severe disease)
• Fixed, dilated bowel loop: Same loop persisting on serial films (suggests ischemic, non-viable bowel)
• Pneumoperitoneum: Free air under diaphragm (perforation - surgical emergency)

Management:

• NPO (bowel rest) - duration based on stage: 10-14 days for confirmed NEC
• Nasogastric decompression (continuous low-pressure suction)
• IV fluids + TPN
• Antibiotics: Ampicillin + Gentamicin + Metronidazole (covers gram-positive, gram-negative, and anaerobes)
• Serial abdominal X-rays Q6-8h (or sooner if deteriorating)
• Cardiovascular support if hypotensive

• Surgical consult for Stage IIB and all Stage III
• Peritoneal drain: Bedside procedure; temporizing measure in VLBW (<1000 g) too unstable for surgery
• Exploratory laparotomy: Resection of necrotic bowel; stoma formation
• Indications: Pneumoperitoneum, clinical deterioration despite medical therapy, peritonitis, abdominal wall cellulitis

• Short bowel syndrome (after extensive resection)
• Stricture formation (occurs in 20-35% of medically treated NEC) - look for feeding intolerance weeks-months later
• TPN-associated cholestasis
• Neurodevelopmental impairment

10.2 Bilious Emesis in the Newborn

• Can present any time in neonate/infant
• Bile-stained vomiting, sudden-onset abdominal pain in a previously well infant
• Can progress to ischemia/gangrene in hours
• UGI (upper GI series) gold standard - "corkscrew" appearance of duodenojejunal junction
• Treatment: Emergency Ladd's procedure

• "Double bubble" on X-ray (gas in stomach + duodenum only - no gas distally)
• Associated with Down syndrome (trisomy 21) in 30%
• Polyhydramnios in pregnancy (fetus cannot swallow amniotic fluid)

• Absence of ganglion cells in distal colon (aganglionic segment)
• Failure to pass meconium within 48 hours of birth
• Contrast enema: Transition zone (narrow aganglionic segment → dilated proximal colon)
• Rectal biopsy: Absent ganglion cells + hypertrophic nerve fibers (gold standard)
• Complication: Hirschsprung-associated enterocolitis (HAEC) - explosive watery/bloody stools, fever, abdominal distension - can be fatal

10.3 Abdominal Wall Defects - Detailed Comparison

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MODULE 11: HEMATOLOGIC DISEASES

11.1 Neonatal Polycythemia

Definition:

• Heel stick can falsely elevate Hct (capillary stasis)
• Arterial sample can falsely lower Hct

Pathophysiology:

Etiologies:

• Intrauterine hypoxia (SGA, post-term, pregnancy-induced hypertension)
• IDM (maternal hyperglycemia → fetal erythropoietin → increased RBC production)
• Congenital adrenal hyperplasia, trisomies (21, 18, 13)
• Beckwith-Wiedemann syndrome

• Twin-to-twin transfusion syndrome (recipient twin)
• Maternal-fetal transfusion
• Delayed cord clamping (more blood received)

Clinical Features:

• Plethora (ruddy, brick-red appearance) - most visible sign
• Respiratory distress, tachypnea
• Hypoglycemia (erythrocytes consume glucose)
• Neurologic: Irritability, lethargy, seizures, poor feeding
• Thrombocytopenia (platelets consumed in microthrombi)
• Hyperbilirubinemia (excess RBC breakdown)
• Cardiac failure (increased viscosity increases cardiac work)

Management:

• Goal: Reduce Hct to <55%
• Volume to exchange = [current Hct - desired Hct] / current Hct × blood volume × weight
  • Blood volume: 80 mL/kg (term), 100 mL/kg (preterm)
• Exchange fluid: Normal saline (isotonic) replaces removed blood
• Exchange in 10-20 mL increments

11.2 Neonatal Anemia

Causes:

1. Blood loss: Feto-maternal hemorrhage, twin-twin transfusion, vasa previa, umbilical cord hemorrhage, adrenal hemorrhage
2. Hemolysis:
   • Immune: ABO incompatibility, Rh incompatibility, minor blood group incompatibility
   • Non-immune: G6PD deficiency, hereditary spherocytosis, pyruvate kinase deficiency
   • Infection
3. Decreased production: Physiologic anemia of infancy, Diamond-Blackfan anemia (rare)

Physiologic Anemia:

• Term: Nadir Hgb ~10-11 g/dL at 8-12 weeks (bone marrow switches from HbF to HbA)
• Preterm: Nadir earlier and lower (~7-8 g/dL at 4-8 weeks)
• Anemia of prematurity: Exaggerated physiologic anemia in preterm infants due to:
  • Phlebotomy losses in NICU
  • Shortened RBC lifespan
  • Blunted EPO response
  • Rapid growth

11.3 Neonatal Alloimmune Thrombocytopenia (NAIT)

• Most common cause of severe thrombocytopenia in neonates
• Mechanism: Mother lacks platelet antigen (usually HPA-1a) → forms IgG antibodies → cross placenta → destroy fetal platelets
• Severely low platelets (<20,000) without maternal thrombocytopenia (differentiates from neonatal ITP where mother also thrombocytopenic)
• High risk of ICH (10-20%) - including in utero
• Treatment: IVIG 1 g/kg; HPA-1a-negative (compatible) platelets if available; no blood products sharing maternal HPA-1a antigen

11.4 Vitamin K Deficiency Bleeding (VKDB) / Hemorrhagic Disease of the Newborn

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MODULE 12: COMMON NEONATAL CONDITIONS

12.1 Neonatal Abstinence Syndrome (NAS) / Neonatal Opioid Withdrawal Syndrome (NOWS)

Background:

• Occurs when opioid-exposed infant is born and maternal drug is discontinued
• Spectrum includes: heroin, methadone, buprenorphine, prescription opioids, alcohol, benzodiazepines, SSRIs, nicotine
• Methadone maintenance therapy correlates with NAS severity in a dose-response relationship
• Buprenorphine (Subutex) is associated with milder NAS than methadone

Clinical Features - Mnemonic "WITHDRAWAL":

• W - Wakefulness
• I - Irritability, insomnia
• T - Tremors, temperature variation, tachypnea, twitching (jitteriness)
• H - Hyperactivity, high-pitched cry, hiccups, hyperreflexia, hypertonia
• D - Diarrhea (explosive), diaphoresis, disorganized suck
• R - Rub marks (from excessive movements), respiratory distress, rhinorrhea, regurgitation
• A - Apnea, autonomic dysfunction
• W - Weight loss
• A - Alkalosis (respiratory)
• L - Lacrimation (photophobia), lethargy
• S - Seizures, sneezing, stuffy nose, sweating, sucking (non-productive)

Onset by Drug:

Scoring: Finnegan Neonatal Abstinence Scoring System (FNAS)

• 21-item behavioral and physiologic scoring
• Total score at each assessment guides treatment
• Score ≥8 three consecutive times → initiate pharmacologic treatment

Management:

• Rooming-in with mother (reduces NAS severity and length of stay)
• Breastfeeding (encouraged if mother in opioid maintenance program, HIV-negative, not using illicit drugs)
• Skin-to-skin contact
• Swaddling, reduced stimulation, quiet environment
• Small frequent feeds (high-calorie formula for poor weight gain)

1. Morphine or methadone (first-line oral opioids)
2. Buprenorphine (emerging evidence for shorter hospital stay)
3. Clonidine (α2-agonist, adjunct therapy - reduces autonomic symptoms)
4. Phenobarbital (for poly-drug exposure, seizures, or opioid non-responsive)

12.2 Infant of a Diabetic Mother (IDM)

Pathophysiology:

• Maternal hyperglycemia → fetal hyperglycemia → fetal hyperinsulinism
• Insulin acts as growth factor → macrosomia (weight >4000g or >90th percentile)
• At birth: Maternal glucose supply cut off → hyperinsulinism continues → neonatal hypoglycemia (occurs within 30 min - 2h of birth)

Clinical Features of IDM:

Management:

• Glucose monitoring: 30 min after first feed, then Q2-4h × 12 hours
• Early feeds (first 30 minutes)
• IV dextrose if symptomatic or glucose <40 mg/dL

12.3 Birth Trauma

Cephalohematoma vs. Caput Succedaneum:

Subgaleal Hemorrhage (most dangerous):

• Blood collects in potential space between scalp aponeurosis (galea) and periosteum
• Crosses suture lines, can expand to massive size (entire scalp)
• Caused by vacuum extraction
• Life-threatening hemorrhage (head can hold up to 260 mL of blood)
• Clinical: Expanding boggy scalp swelling, pallor, shock
• Management: Aggressive blood transfusion, coagulation support

Brachial Plexus Injuries (Harriet Lane Table 18.12):

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MODULE 13: THE PRETERM INFANT

13.1 Overview of Prematurity

Global Burden:

• ~15 million preterm births per year worldwide
• Leading cause of neonatal mortality
• Survival rates: ~50% at 23 weeks; ~80% at 25 weeks; >90% at 28 weeks at centers with intensive care

Viability:

• 22 weeks: Periviable - individualized counseling required; intensive care optional
• 22-24 weeks: Periviable - intensive care offered; significant morbidity if survive
• 25+ weeks: Threshold where most centers offer full intensive care
• Depends on: GA, birth weight, sex (females do better), antenatal steroids (most important modifiable factor)

13.2 Bronchopulmonary Dysplasia (BPD)

Definition (NICHD 2019 updated criteria):

Severity Grading:

Pathophysiology ("New BPD"):

• Old BPD (pre-surfactant era): Fibrosis, scarring from barotrauma
• New BPD (current era): Arrested lung development due to:
  • Premature lung exposed to extrauterine environment too early
  • Oxygen toxicity → ROS → impaired alveolarization
  • Inflammation (cytokines from ventilator-induced lung injury)
  • Infection (chorioamnionitis, postnatal sepsis)
  • Hemodynamic shunting (PDA)
• Result: Fewer, larger, simplified alveoli; abnormal vasculature → pulmonary hypertension

Management:

Outcomes:

• BPD infants have increased rates of asthma, neurodevelopmental impairment, school-age learning difficulties
• Pulmonary hypertension in 17-30% of severe BPD

13.3 Retinopathy of Prematurity (ROP)

Pathophysiology:

• Retinal vessels grow from optic disc outward (centrifugal) from ~16 weeks gestation
• Reach nasal ora serrata by ~36 weeks; temporal by ~40 weeks
• Incomplete at birth in preterm infants

ROP Classification:

• Zone I: Circle around optic disc (most posterior, worst prognosis)
• Zone II: From edge of Zone I to nasal ora serrata
• Zone III: Remaining crescent temporal retina (least severe location)

Screening Criteria (AAP 2019):

• All infants born ≤30 weeks GA OR birth weight <1500 g
• Infants born >30 weeks with unstable clinical course (cardiorespiratory support)
• First exam timing:
  • Born ≤27 weeks → first exam at 31 weeks PMA
  • Born 28 weeks or more → first exam at 4 weeks chronologic age
  • Born <25 weeks → consider 6 weeks chronologic age (even if before 31 weeks PMA)

Treatment (Harriet Lane - Module XIV):

• Zone I: Any stage + plus disease
• Zone I: Stage 3 without plus disease
• Zone II: Stage 2 or 3 + plus disease

1. Laser photocoagulation: Ablates avascular peripheral retina → eliminates VEGF signal; preferred for Zone II disease
2. Intravitreal anti-VEGF (bevacizumab): First-line for Zone I disease (peripheral laser cannot reach Zone I safely); concern for systemic VEGF suppression in premature infants; reactivation can occur weeks later → need careful follow-up

• Zone I: Stage 1-2 without plus disease
• Zone II: Stage 3 without plus disease → Serial exams every 1-2 weeks

• Within 1 week if Zone I disease
• Every 2-3 weeks until full vascularization confirmed

13.4 Other Complications of Prematurity

Metabolic Bone Disease of Prematurity (Rickets of Prematurity):

• Inadequate calcium and phosphorus accretion (most fetal bone mineralization occurs in 3rd trimester)
• Risk factors: VLBW, chronic illness, prolonged PN, medications (furosemide leaches calcium, steroids impair bone formation)
• Clinical: Fractures with minimal trauma, hypophosphatemia, elevated ALP
• Prevention/Treatment: Calcium + phosphorus supplements; Vitamin D; breastmilk fortifier

Hypothermia in Preterm Infants:

• Preterm infants cannot thermoregulate (lack brown fat, large surface area/weight ratio, minimal subcutaneous fat, immature skin)
• Prevention: Delivery in warm room (26°C), polyethylene wrap at <30 weeks (reduces evaporative heat loss), radiant warmer, early use of servo-controlled incubator
• Cold stress → metabolic acidosis, hypoglycemia, pulmonary vasoconstriction, coagulopathy

Late Preterm Infants (34-36+6 weeks) - Special Considerations:

• RDS (surfactant deficiency)
• TTN
• Hypoglycemia
• Hyperbilirubinemia (jaundice up to 21 days)
• Temperature instability
• Feeding difficulties (immature suck-swallow coordination)
• Higher SIDS risk than term infants
• Lower threshold for NICU admission

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MODULE 14: NEONATAL PHARMACOLOGY - COMPLETE DRUG GUIDE

14.1 NICU Antimicrobials (Harriet Lane Table 18.13)

14.2 Respiratory Drugs

14.3 Cardiovascular Drugs

14.4 Neurological Drugs

14.5 Prophylactic and Routine Drugs

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INTEGRATIVE CLINICAL PEARLS - ALL MODULES

Must-Know Clinical Decision Points:

Pharmacology Decision Rules:

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What You Now Have - Complete Deep Neonatology Notes