Congenital diaphragmatic hernia

Congenital diaphragmatic hernia

Congenital diaphragmatic hernia

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🕳️ Anatomy - A Hole in the Floor

A developmental defect in the diaphragm from incomplete fusion of pleuroperitoneal membranes, typically by week 8-10 of gestation. This allows abdominal viscera to enter the thorax.

CDH: Normal vs. anomalous development & Bochdalek hernia

  • Bochdalek Hernia (Posterolateral):
    • Most common type (~85%).
    • Defect in the foramen of Bochdalek.
    • 📌 Bochdalek = Back & lateral.
  • Morgagni Hernia (Anteromedial):
    • Rare, defect in the foramen of Morgagni.

85% of Bochdalek hernias are on the left. The liver's position on the right may physically block herniation, and the right pleuroperitoneal canal closes earlier.

🌬️ Pathophysiology - Lungs Under Pressure

CDH: Normal vs. Anomalous Development & Embryology

  • Primary issue: Pulmonary hypoplasia & pulmonary hypertension, not the diaphragmatic hole itself. Herniation during lung organogenesis compresses the developing lungs, leading to:
    • ↓ Alveoli & bronchioles.
    • Thickened pulmonary arterioles → ↑ Pulmonary Vascular Resistance (PVR).
    • Commonly, surfactant deficiency.

⭐ The main cause of mortality is severe pulmonary hypoplasia and persistent pulmonary hypertension (PPHN), leading to right-to-left shunting and profound hypoxemia.

👶 Clinical Manifestations - The Empty Belly Blues

  • Immediate Postnatal Distress:

    • Severe respiratory distress (cyanosis, tachypnea, retractions).
    • Often requires immediate intubation.
  • Physical Exam Findings:

    • Scaphoid abdomen: "Empty belly" as contents are in the chest.
    • Barrel-shaped chest: Due to herniated viscera.
    • Auscultation: Bowel sounds in chest; ↓/absent breath sounds on affected side.
    • Displaced heart sounds: Apex beat shifted away from hernia.

Left-sided (Bochdalek) hernias are most common (~85%), leading to a rightward mediastinal shift.

🩺 Diagnosis - Seeing the Unseen

  • Prenatal: Routine ultrasound may show polyhydramnios, an intrathoracic stomach bubble, and mediastinal shift.
  • Postnatal:
    • Clinical: Severe respiratory distress at birth, scaphoid abdomen, barrel-shaped chest.
    • Auscultation: Bowel sounds in the chest; absent breath sounds on the affected side (usually left).

⭐ Chest X-ray is the definitive diagnostic test, showing gas-filled loops of bowel in the hemithorax and contralateral mediastinal shift.

🛠️ Management - The Repair Crew

  • Initial: Intubate immediately, place NG tube for bowel decompression. ⚠️ Avoid bag-mask ventilation (insufflates stomach/bowel).
  • Ventilation: Gentle, low-pressure ventilation; permissive hypercapnia is often targeted.
  • Pulmonary HTN: Treat aggressively with inhaled nitric oxide (iNO), sildenafil.
  • ECMO: Bridge to surgery for severe respiratory failure or refractory pulmonary hypertension.

⭐ The primary cause of mortality is pulmonary hypoplasia and persistent pulmonary hypertension (PPHN), not the hernia itself. Surgery is delayed until the patient is stable.

⚡ Biggest Takeaways

  • Most common type is a left posterolateral Bochdalek hernia, allowing abdominal contents into the thorax.
  • Pulmonary hypoplasia and pulmonary hypertension are the primary drivers of mortality, not the defect itself.
  • Classic triad: respiratory distress from birth, a scaphoid abdomen, and bowel sounds in the chest.
  • Initial management is critical: intubate immediately and place an orogastric tube. AVOID bag-mask ventilation.
  • Surgical repair is performed only after medical stabilization, focusing on managing pulmonary hypertension.

Practice Questions: Congenital diaphragmatic hernia

Test your understanding with these related questions

A 42-year-old woman presents to the emergency department in active labor. She has had no prenatal care and is unsure of the gestational age. Labor progresses rapidly and spontaneous vaginal delivery of a baby boy occurs 3 hours after presentation. On initial exam, the child is 1.9 kg (4.2 lb) with a small head and jaw. A sac-like structure containing intestine, as can be seen in the picture, protrudes from the abdominal wall. What complication is closely associated with this presentation?

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Flashcards: Congenital diaphragmatic hernia

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What is the most common type of diaphragmatic hernia? _____

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What is the most common type of diaphragmatic hernia? _____

Sliding hiatal hernia

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