Pediatrics 1 : neonatology detailed notes exam oriented
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Pediatrics 1 — Neonatology: Exam-Oriented Notes
Source: The Harriet Lane Handbook 23rd Ed (Johns Hopkins Hospital) • Tintinalli's Emergency Medicine • Robbins Pathology • Creasy & Resnik Maternal-Fetal Medicine
1. NEWBORN ASSESSMENT
Birth Weight Classification
| Term | Definition |
|---|---|
| ELBW | Extremely Low Birth Weight < 1000 g |
| VLBW | Very Low Birth Weight < 1500 g |
| LBW | Low Birth Weight < 2500 g |
| SGA | Small for Gestational Age < 10th percentile |
| LGA | Large for Gestational Age > 90th percentile |
APGAR Score (Assessed at 1 min and 5 min; repeat every 5 min if score <7 at 5 min)
| Component | 0 | 1 | 2 |
|---|---|---|---|
| Appearance (Color) | Blue/pale | Acrocyanosis | Completely pink |
| Pulse (Heart Rate) | Absent | <100 bpm | >100 bpm |
| Grimace (Reflex) | No response | Grimace | Cough/sneeze |
| Activity (Muscle Tone) | Limp | Some flexion | Active motion |
| Respiration | Absent/irregular | Slow, weak cry | Good, strong cry |
Score interpretation: 7–10 = Normal | 4–6 = Moderate depression | 0–3 = Severe depression
Ballard Score (Gestational Age Estimation)
- Used when obstetric dating unavailable; most accurate at ~24 hours
- Combines neuromuscular (posture, square window, arm recoil, popliteal angle, scarf sign, heel-to-ear) and physical maturity criteria
- Scarf sign: score 0 = elbow crosses to opposite axillary line; score 3 = cannot reach midline
Vital Signs (Term Newborn)
- RR: 30–60/min; HR: 100–160/min; BP (mean arterial): related to gestational age
- Temperature: 36.5–37.5°C (axillary)
2. NEWBORN RESUSCITATION (NRP Algorithm)
Equipment Required
Radiant warmer, prewarmed blankets, hat, bag-mask/NeoPIP ventilator, appropriately sized laryngoscope, ETT ± stylet, suction device, emergency medications, vascular access supplies.
ETT Sizing (Quick Reference)
| Gestational Age | ETT Size | Insertion Depth |
|---|---|---|
| <30 weeks | 2.5 mm | Weight (kg) + 6 cm |
| 30–34 weeks | 3.0 mm | |
| >35 weeks | 3.5 mm |
Key Points
- Meconium-stained fluid: Routine intrapartum suctioning NOT recommended (even for nonvigorous infants)
- Delayed cord clamping: ≥30–60 seconds for vigorous term AND preterm infants
- Cord milking: contraindicated <28 weeks (linked to IVH); insufficient evidence 28–32 weeks
- Umbilical venous catheter (UVC): In emergencies, insert just far enough for blood return — no measurement needed
Absolute Exclusions for Delayed Cord Clamping
Monochorionic twins, discordant twins >25%, IUGR <3rd percentile with reversed end-diastolic flow, congenital diaphragmatic hernia, abdominal wall defects, maternal placental abruption, uterine rupture.
3. RESPIRATORY DISORDERS OF THE NEWBORN
A. Respiratory Distress Syndrome (RDS) / Hyaline Membrane Disease
- Etiology: Deficiency of pulmonary surfactant → increased surface tension → alveolar collapse
- Surfactant produced in increasing quantities after 32 weeks
- Risk factors: Prematurity, maternal diabetes, C-section without labor, perinatal asphyxia, second twin
- Protective factors (accelerate lung maturity): Hypertension, sickle cell disease, narcotic addiction, IUGR, PROM, fetal stress
Incidence by Gestational Age
| Gestational Age | With Antenatal Steroids | Without Antenatal Steroids |
|---|---|---|
| <30 weeks | 35% | 60% |
| 30–34 weeks | 10% | 25% |
| 34–36 weeks | ~1.4–5.5% | ~2.3–6.4% |
| >37 weeks | 2.6% | 5.4% |
- Clinical presentation: Respiratory distress worsens in first hours, peaks at 48–72 hrs, then improves; recovery accompanied by brisk diuresis
- CXR: Hypoinflation + diffuse/symmetric "ground glass" appearance
- Prevention: Antenatal corticosteroids — optimal timing: >24 hours and <7 days before anticipated preterm delivery; repeat course if GA <34 weeks and prior course >14 days ago
- Management: Ventilatory support + surfactant therapy
B. Transient Tachypnea of the Newborn (TTN)
- Etiology: Delayed resorption of amniotic fluid (immature Na⁺ transport by respiratory epithelium)
- Risk factors: C-section, male sex, macrosomia, lower GA, maternal diabetes/asthma/smoking
- Clinical features:
- Onset within first 6 hours, resolves within 72 hours (within first postnatal week)
- Tachypnea >60/min (often 80–100/min)
- Retractions, grunting, nasal flaring; cyanosis and hypoxia are rare
- CXR: Fluid in fissures, hyperinflation, perihilar streaking
C. Meconium Aspiration Syndrome (MAS)
- Occurs in term/post-term infants; meconium-stained amniotic fluid aspirated before/during birth
- Features: Respiratory distress, hyperinflation, CXR shows patchy infiltrates + air trapping
- Complication: PPHN
D. Persistent Pulmonary Hypertension of the Newborn (PPHN)
- Etiology: Idiopathic or secondary to elevated PVR with right-to-left shunting (at PFO/PDA)
- Risk factors: Term/post-term, C-section, fetal distress, low APGAR, hypoxemia, acidosis, meconium aspiration, pulmonary hypoplasia, diaphragmatic hernia/renal agenesis
- Key diagnostic clue: Severe hypoxemia (PaO₂ <35–45 mmHg in 100% O₂) disproportionate to radiologic changes; pre/post-ductal O₂ gradient ≥7–15 mmHg
- Treatment:
- Optimize oxygenation; avoid severe hypocarbia (PCO₂ <30 mmHg)
- Maintain systemic BP (volume + inotropes)
- Inhaled nitric oxide (iNO): Starting dose 20 ppm; reduce if methemoglobin >4%
- Sildenafil (PDE5 inhibitor) → pulmonary vasodilation
- ECMO if OI >40 for >3 hours; infant >2000 g, >34 weeks
4. NEONATAL JAUNDICE / HYPERBILIRUBINEMIA
Physiologic vs. Pathologic Jaundice
| Feature | Physiologic | Pathologic |
|---|---|---|
| Onset | After 24 hours | Within 24 hours |
| Peak (term) | Day 3–4, <12 mg/dL | Any time, >12 mg/dL |
| Duration (term) | <1 week | >1–2 weeks |
| Direct bilirubin | <2 mg/dL | >2 mg/dL |
Rule: Any jaundice OR TSB >5 mg/dL in first 24 hours = PATHOLOGIC until proven otherwise.
Risk Factors for Severe Hyperbilirubinemia
Isoimmune hemolytic disease, G6PD deficiency, asphyxia, significant lethargy, temperature instability, sepsis, acidosis, albumin <3.0 g/dL, birth weight <2500 g, exclusive breastfeeding, prematurity, ABO incompatibility.
Management
a) Phototherapy
- Term infants (≥35 weeks): Use AAP/Bhutani nomogram (high/medium/low risk curves)
- Intensive phototherapy → TSB decline of 1–2 mg/dL within 4–6 hours
Preterm phototherapy thresholds (age <1 week):
| Gestational Age | Start Phototherapy | Consider Exchange Transfusion |
|---|---|---|
| <28 weeks | 5–6 mg/dL | 11–14 mg/dL |
| 28–29 6/7 weeks | 6–8 mg/dL | 12–14 mg/dL |
| 30–31 6/7 weeks | 8–10 mg/dL | 13–16 mg/dL |
| 32–33 6/7 weeks | 10–12 mg/dL | 15–18 mg/dL |
b) IVIG: In isoimmune hemolytic disease: 0.5–1 g/kg over 2 hours if TSB rising despite phototherapy or within 2–3 mg/dL of exchange transfusion level
c) Double-volume exchange transfusion
- Volume: 160 mL/kg (term), 200 mL/kg (preterm)
- Route: Blood removed via UAC, equal volume infused via UVC
- Replaces ~85% of infant's circulation; exchange in 15 mL aliquots (term) or 2–3 mL/kg/min (preterm)
5. NEONATAL SEPSIS
Classification
| Early-Onset (<7 days) | Late-Onset (>7 days) | |
|---|---|---|
| Presentation | Fulminant | More gradual |
| Risk factors | Maternal fever, GBS+, PROM, fetal distress | Less associated with maternal factors |
| Common complication | Septic shock, neutropenia | Meningitis more common |
Signs of Neonatal Sepsis
- Temperature instability (fever ≥38°C rectally or hypothermia <36.5°C)
- CNS: Lethargy, irritability, seizures
- Respiratory: Apnea, tachypnea, grunting — most common presenting feature
- GI: Vomiting, poor feeding, gastric distension, diarrhea
- Jaundice, rashes
Causative Organisms
- Early-onset: Group B Streptococcus (GBS), E. coli, Listeria monocytogenes, Klebsiella
- Late-onset: Coagulase-negative Staph (CoNS in NICU), GBS, E. coli, Candida
- Viral: Enteroviruses (coxsackievirus, echovirus); acquired at delivery or postnatally
Workup
Full sepsis evaluation: Blood culture, CBC, CRP, LP for CSF (meningitis screen), urine culture; threshold for LP is lower in neonates than older infants.
6. TORCH INFECTIONS
| Organism | Key Features | Neonatal Findings |
|---|---|---|
| Toxoplasma | Cat litter/raw meat; mothers often asymptomatic | Hydrocephalus, intracranial calcifications (periventricular), chorioretinitis; classic triad |
| Other (Syphilis, VZV, Parvovirus B19, Zika, HBV, HIV) | Various | Rash, bone lesions (syphilis); hydrops (parvo B19) |
| Rubella | First trimester worst | Cataracts, PDA, sensorineural deafness, blueberry muffin rash |
| CMV | Most common congenital infection | Periventricular calcifications, SNHL (most common cause), hepatosplenomegaly, microcephaly, thrombocytopenia, blueberry muffin spots |
| Herpes (HSV) | Often HSV-2; acquisition during delivery | Skin-eye-mouth (SEM), encephalitis, disseminated; vesicular rash |
CMV vs. Toxoplasma calcification pattern:
- CMV → periventricular calcifications
- Toxoplasma → diffuse/scattered calcifications
7. NECROTIZING ENTEROCOLITIS (NEC)
Definition
Serious intestinal inflammation and injury (multifactorial: bowel ischemia + immaturity + infection); primarily in premature infants who have been fed.
Risk Factors
Prematurity, RDS, HIE, polycythemia-hyperviscosity, umbilical vessel catheterization, exchange transfusion, bacterial/viral pathogens, enteral feeds, PDA, congestive heart failure, cyanotic heart disease.
Modified Bell's Staging
| Stage | Description |
|---|---|
| IA – Suspected | Temperature instability, apnea, bradycardia, lethargy, mild abdominal distension, gastric residuals, occult blood in stool; X-ray: normal to mild ileus |
| IB – Suspected | As IA but gross blood in stool |
| IIA – Definite, mildly ill | Pneumatosis intestinalis, absent bowel sounds ± tenderness |
| IIB – Definite, moderately ill | IIA + metabolic acidosis, mild thrombocytopenia, abdominal tenderness ± cellulitis/RLQ mass ± portal venous gas |
| IIIA – Advanced, bowel intact | Hypotension, bradycardia, apnea, DIC, peritonitis, ascites |
| IIIB – Advanced, perforated | Pneumoperitoneum |
Pathognomonic X-ray finding: Pneumatosis intestinalis (air in bowel wall) Portal venous gas = advanced disease
Management
- Stages I–IIA: NPO, IV antibiotics (ampicillin + gentamicin ± metronidazole), NG decompression
- Stage III / perforation: Surgical consultation (peritoneal drain or laparotomy)
8. HYPOXIC-ISCHEMIC ENCEPHALOPATHY (HIE)
Criteria for Therapeutic Hypothermia (≥35 weeks GA)
Initiate within 6 hours of delivery:
- Cord gas or blood gas pH <7.0 OR base deficit >16 in first hour
- If pH 7.01–7.15 or base deficit 10–15.9, additional criteria needed:
- 10-minute APGAR ≤5
- Evidence of moderate to severe encephalopathy
- Need for assisted ventilation at birth ≥10 minutes
Sarnat Classification of HIE
| Feature | Mild (Grade I) | Moderate (Grade II) | Severe (Grade III) |
|---|---|---|---|
| Consciousness | Hyperalert/irritable | Lethargic | Stupor/coma |
| Seizures | Rare | Common | Uncommon |
| Primitive reflexes | Exaggerated | Suppressed | Absent |
| Brain stem dysfunction | Rare | Rare | Common |
| Elevated ICP | Rare | Rare | Variable |
| Duration | <24 hours | >24 hours (variable) | >5 days |
| Poor outcome | 0% | 20–40% | 100% |
9. INTRAVENTRICULAR HEMORRHAGE (IVH)
Epidemiology
- 30–40% of infants <1500 g; 50–60% of infants <1000 g
- 50% occur within 24 hours of birth; 90% within 96 hours
- Arises in the germinal matrix (periventricular region)
Grading (Ultrasonography)
| Grade | Description |
|---|---|
| I | Hemorrhage in germinal matrix only |
| II | IVH without ventricular dilation |
| III | IVH with ventricular dilation |
| IV | Periventricular hemorrhagic infarct ± IVH |
- Grade III–IV → increased risk for neurodevelopmental disabilities + posthemorrhagic hydrocephalus
Screening
Indicated in: infants <32 weeks GA or birth weight <1500 g within 72 hours of birth; repeat in 1–2 weeks.
10. HEMATOLOGIC CONDITIONS
Neonatal Polycythemia
- Definition: Venous hematocrit >65% (confirmed on 2 consecutive samples)
- Causes: Twin-twin transfusion, maternal-fetal transfusion, intrauterine hypoxia, maternal diabetes, delayed cord clamping, neonatal thyrotoxicosis, trisomies, Beckwith-Wiedemann
- Features: Plethora, respiratory distress, hypoglycemia, irritability, seizures, thrombocytopenia, hyperbilirubinemia
- Complication: Hyperviscosity → venous thrombosis, CNS injury, hypoglycemia (increased RBC glucose consumption)
- Management: Partial-volume exchange transfusion (symptomatic infants); isovolemic replacement 80 mL/kg (term) / 100 mL/kg (preterm); exchange in 10–20 mL increments to goal Hct <55%
11. NEONATAL HYPOGLYCEMIA
Definition
Blood glucose <45–50 mg/dL (clinical threshold varies; symptomatic below 40 mg/dL)
At-Risk Groups
- Infants of diabetic mothers (IDM) — hyperinsulinism
- SGA / IUGR — reduced glycogen stores
- Prematurity — reduced gluconeogenesis
- LGA / macrosomia
- Perinatal asphyxia
Clinical Features
Jitteriness, poor feeding, hypotonia, apnea, seizures, temperature instability, cyanosis
Management
- Asymptomatic: Early enteral feeding; glucose gel 0.5 mL/kg buccally
- Symptomatic: IV dextrose bolus (D10W 2 mL/kg) followed by continuous infusion
12. NEUROLOGICAL CONDITIONS
Neonatal Seizures
- Causes (in order): HIE (most common), metabolic (hypoglycemia, hypocalcemia, hyponatremia), infection (meningitis), IVH, inborn errors of metabolism, drug withdrawal
- Types: Subtle (most common — lip smacking, eye deviation, cycling), focal clonic, multifocal clonic, myoclonic, tonic
- Investigation: Glucose, Ca, Na, Mg, LP, EEG, head ultrasound, MRI
- Treatment: Correct metabolic causes → phenobarbital (first-line) → levetiracetam, phenytoin
Neonatal Abstinence Syndrome (NAS)
- Onset usually within 24–72 hours (methadone can delay to >96 hours); symptoms may last weeks-months
- Mnemonic "DRAW-ALS":
- D – Diarrhea, diaphoresis, disturbed sleep
- R – Rub marks, respiratory distress, rhinorrhea, regurgitation
- A – Apnea, autonomic dysfunction
- W – Weight loss
- A – Alkalosis (respiratory)
- L – Lacrimation, lethargy
- S – Seizures, sneezing, sweating, stuffy nose, sucking (nonproductive)
- Assessment: Finnegan Neonatal Abstinence Scoring System
- Management: Non-pharmacologic (swaddling, low stimulation, breastfeeding) → morphine/methadone if pharmacologic therapy needed
13. BIRTH INJURIES
Brachial Plexus Injuries
| Type | Levels | Features |
|---|---|---|
| Erb-Duchenne palsy (90%) | C5–C6 (± C4) | Adduction + internal rotation of arm; forearm pronated, wrist flexed ("waiter's tip"); diaphragm paralysis if C4 involved |
| Total palsy (8–9%) | C5–T1 (± C4) | Entire arm involved; Horner syndrome if T1 involved |
| Klumpke paralysis (<2%) | C7–T1 | Hand flaccid; Horner if T1 involved |
14. GASTROINTESTINAL ANOMALIES
Omphalocele vs. Gastroschisis (High-Yield Comparison)
| Feature | Omphalocele | Gastroschisis |
|---|---|---|
| Position | Central (umbilical) | Right paraumbilical |
| Hernia sac | Present | Absent |
| Umbilical cord insertion | At vertex of sac | Normal |
| Associated anomalies | Frequent (cardiac, Beckwith-Wiedemann) | Rare |
| Intestinal infarction/atresia | Less frequent | More frequent |
| Umbilical ring | Absent | Present |
Bilious Emesis in Neonate — Key Differentials
| Proximal Obstruction | Distal Obstruction | |
|---|---|---|
| DDx | Duodenal atresia, annular pancreas, malrotation ± volvulus | Ileal atresia, meconium ileus, Hirschsprung, meconium plug |
| X-ray | "Double bubble" | Dilated loops of bowel |
| Workup | Upper GI series | Contrast enema, sweat test, rectal biopsy |
Bilious vomiting in a neonate = emergency until malrotation with volvulus excluded
15. RETINOPATHY OF PREMATURITY (ROP)
Pathophysiology
Exposure of immature retina to high O₂ → vasoconstriction + obliteration of capillary network → abnormal vasoproliferation
Screening Criteria
- All infants ≤30 weeks GA or birth weight <1500 g
- Infants >30 weeks with unstable clinical course (requiring cardiorespiratory support)
Screening Timing
- ≤27 weeks: Initial ROP exam at 31 weeks postmenstrual age
- ≥28 weeks: Initial exam at 4 weeks chronologic age
- <25 weeks: Consider earlier at 6 weeks chronologic age
Staging (Zone I–III + Stage 1–5)
- Stage 1: Demarcation line
- Stage 2: Ridge
- Stage 3: Ridge with extraretinal fibrovascular proliferation
- Stage 4: Partial retinal detachment
- Stage 5: Total retinal detachment
- Plus disease: Dilation and tortuosity of posterior retinal vessels (indicates active ROP)
16. PREMATURITY — OVERVIEW & COMPLICATIONS
Definition
- Preterm: <37 weeks gestation
- Extreme preterm: <28 weeks
- Very preterm: 28–32 weeks
- Late preterm: 34–36 6/7 weeks
Major Complications by System
| System | Complication |
|---|---|
| Pulmonary | RDS, BPD (chronic lung disease), apnea of prematurity |
| CNS | IVH, periventricular leukomalacia (PVL), cerebral palsy |
| GI | NEC, feeding intolerance |
| Eyes | ROP |
| CVS | Patent ductus arteriosus (PDA) |
| Metabolic | Hypoglycemia, hypocalcemia, hypothermia |
| Immune | Increased susceptibility to sepsis |
Periventricular White Matter Injury (PVL)
- Ischemic necrosis of periventricular white matter
- Etiology: Ischemia-reperfusion, infection, hypoxia, hypoglycemia
- Outcome: Cerebral palsy (spastic diplegia most common), sensory/cognitive deficits
- Ultrasound: Cysts in periventricular area or noncystic white matter injury on MRI
17. QUICK-FIRE EXAM FACTS
| Fact | Answer |
|---|---|
| Most common cause of neonatal cardiorespiratory distress | Sepsis |
| First-line drug for neonatal seizures | Phenobarbital |
| Pathognomonic X-ray finding of NEC | Pneumatosis intestinalis |
| Surfactant deficiency → disease | Hyaline membrane disease (RDS) |
| PPHN treatment agent | Inhaled nitric oxide (iNO) |
| Exchange transfusion volume (term) | 160 mL/kg (double volume) |
| Jaundice in first 24 hours | Always pathologic |
| IVH screening in preterm: when? | Within 72 hours if <32 weeks or <1500 g |
| Therapeutic hypothermia window for HIE | Within 6 hours of birth |
| Most common congenital infection | CMV |
| CMV calcification location | Periventricular |
| Toxoplasma calcification location | Diffuse/scattered |
| Rubella triad | Cataracts + PDA + sensorineural deafness |
| Erb-Duchenne palsy levels | C5–C6 |
| ROP: screening starts at (≥28 wks) | 4 weeks chronologic age |
| Delayed cord clamping: when to delay | ≥30–60 sec for vigorous term/preterm |
| Cord milking: contraindicated | <28 weeks (IVH risk) |
| NAS onset (opioids) | 24–72 hours (methadone: may delay to >96 hours) |
| Polycythemia definition | Venous Hct >65% on 2 consecutive samples |
| Omphalocele vs. Gastroschisis: sac | Omphalocele has sac; gastroschisis does not |
| TTN resolves within | 72 hours |
| HIE severe grade: outcome | 100% poor outcome |
— The Harriet Lane Handbook 23rd Ed (Johns Hopkins) | Tintinalli's Emergency Medicine | Robbins & Kumar Basic Pathology | Creasy & Resnik Maternal-Fetal Medicine
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