Congenital Diaphragmatic Hernia

Introduction & Embryology - Hernia Hullabaloo

• Definition: Congenital Diaphragmatic Hernia (CDH) is a developmental defect in the diaphragm, allowing abdominal viscera to herniate into the thoracic cavity.
• Incidence: Occurs in approximately 1 in 2,500 to 1 in 4,000 live births.
• Embryology:
  • Diaphragm develops from fusion of four key structures (📌 Mnemonic: Septum transversum, Pleuroperitoneal membranes, dorsal Mesentery of esophagus, Muscle ingrowth from lateral body walls - "Some People Make Mistakes").
  • Defect arises from failed closure of the pleuroperitoneal canal, typically between 8-10 weeks of gestation.
  • Leads to pulmonary hypoplasia and persistent pulmonary hypertension (PPHN).

⭐ Bochdalek hernia (postero-lateral defect, usually left) is the most common type, accounting for 85-90% of CDH cases. Left-sided cases are more frequent (~85%) than right-sided (~13%).

Clinical Features & Diagnosis - Spotting the Gap

• Presentation (Often at birth):
  • Severe respiratory distress (tachypnea, retractions, grunting).
  • Cyanosis.
  • Scaphoid abdomen.
  • Barrel-shaped chest (unilateral).
  • ↓/absent breath sounds (usually left).
  • Bowel sounds in chest.
  • Apparent dextrocardia (heart sounds shifted).
  • 📌 Mnemonic: CDH = Cyanosis, Dyspnea, Heart shifted & Herniated bowel sounds.
• Key Pathophysiology: Pulmonary hypoplasia & Persistent Pulmonary Hypertension (PPHN).
• Associated Anomalies: Common (cardiac most frequent, ~20-30%).
• Prenatal Diagnosis:
  • Antenatal USG: Polyhydramnios, stomach/bowel in chest, mediastinal shift.
  • LHR / o/e LHR (from USG) for prognosis.
  • Fetal MRI: Details anatomy, lung volume.
• Postnatal Diagnosis:
  • CXR (Confirmatory): Bowel loops in chest, mediastinal shift, ↓ abdominal gas.
  • ABG: Assesses hypoxia, hypercapnia, acidosis.
  • Echocardiogram: Exclude cardiac defects, assess PPHN severity.

⭐ Most CDH cases (~85%) are left-sided posterolateral (Bochdalek) hernias.

Management & Prognosis - Fixing the Flaw

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High‑Yield Points - ⚡ Biggest Takeaways

• Bochdalek hernia (posterolateral, 85% left-sided) is the most common CDH.
• Caused by defective closure of the pleuroperitoneal membrane.
• Pulmonary hypoplasia and persistent pulmonary hypertension (PPHN) are critical determinants of outcome.
• Classic triad: Respiratory distress at birth, scaphoid abdomen, bowel sounds in chest.
• Diagnosis: Chest X-ray (bowel in thorax, mediastinal shift); prenatal ultrasound for early detection.
• Management: Immediate intubation, gentle ventilation, gastric decompression; delayed surgical repair. Avoid bag-mask ventilation.
• Lung-to-head ratio (LHR) on prenatal ultrasound is a key prognostic indicator for severity and survival.