Summary

Congenital Diaphragmatic Hernia (CDH) is a birth defect where there is a defect in the diaphragm (most commonly left-sided, posterolateral – Bochdalek hernia), allowing abdominal organs (stomach, intestines, liver, spleen) to herniate into the chest during fetal development. This compresses the developing lungs, causing pulmonary hypoplasia (underdeveloped lungs) and pulmonary hypertension, which are the main determinants of morbidity and mortality. CDH presents at birth with respiratory distress, scaphoid (sunken) abdomen, and displaced heart sounds. Management requires immediate intubation (NOT bag-mask ventilation), gentle ventilation (permissive hypercapnia), treatment of pulmonary hypertension, and surgical repair once stabilised. ECMO (Extracorporeal Membrane Oxygenation) may be required for severe cases.

Key Facts

• Incidence: ~1 in 2500-3000 live births.
• Location: Left-sided (Bochdalek) ~85%. Right-sided ~15%.
• Key Features: Scaphoid abdomen, Respiratory distress, Displaced heart sounds.
• Main Prognostic Factors: Degree of Pulmonary Hypoplasia, Presence of Liver herniation, Lung-to-Head Ratio (LHR) on antenatal USS.
• DO NOT Bag-Mask Ventilate: Inflates stomach in chest -> Worsens lung compression.
• Treatment: Gentle Ventilation, NO/iNO for PPHN, ECMO if needed, Delayed Surgical Repair.

Clinical Pearls

"Scaphoid Abdomen": The abdomen appears sunken/flat because abdominal contents are in the chest. A key clinical clue at birth.

"DON'T Bag-Mask – Intubate": Bag-mask ventilation pushes air into the stomach (which is in the chest), worsening pulmonary compression. Immediate intubation is critical.

"Gentle Ventilation": Target permissive hypercapnia (pH 7.2-7.25, CO2 up to 60-65 mmHg). Avoid barotrauma to the hypoplastic lungs.

"It's Not the Hole, It's the Lungs": Mortality in CDH is primarily due to pulmonary hypoplasia and pulmonary hypertension, not the diaphragmatic defect itself.

Why This Matters Clinically

CDH is a major neonatal surgical emergency. Outcomes have improved significantly with the shift from immediate surgery to a "gentle ventilation" and stabilisation-first approach. Antenatal diagnosis and delivery at a specialist centre dramatically improve survival.

Survival

Prognostic Indicators (Poor Prognosis)

Long-Term Complications

Key Guidelines / Resources

Key Evidence

Scenario 1:

• Stem: A baby is born at term with immediate respiratory distress. Examination reveals a scaphoid abdomen and absent breath sounds on the left. Heart sounds are displaced to the right. What is the likely diagnosis?
• Answer: Congenital Diaphragmatic Hernia (CDH) – Left-sided (Bochdalek).

Scenario 2:

• Stem: A neonate with suspected CDH is in respiratory distress. An inexperienced colleague prepares to bag-mask ventilate. What should you advise?
• Answer: DO NOT bag-mask ventilate. This will inflate the stomach (which is in the chest) and worsen pulmonary compression. IMMEDIATE INTUBATION is required.

Scenario 3:

• Stem: What are the main determinants of mortality in CDH?
• Answer: Pulmonary Hypoplasia and Persistent Pulmonary Hypertension of the Newborn (PPHN). It's not the hole – it's the lungs.

Scenario 4:

• Stem: What is the ventilation strategy in CDH?
• Answer: Gentle Ventilation. Low peak inspiratory pressures. Permissive hypercapnia (Accept CO2 up to 60-65 mmHg, pH ≥7.20). Avoid barotrauma.

What is Congenital Diaphragmatic Hernia?

CDH is a condition where a baby is born with a hole in the muscle that separates the chest from the tummy (the diaphragm). Before birth, parts of the tummy (like the intestines) move up through the hole into the chest. This stops the lungs from growing properly.

What are the symptoms?

• Difficulty breathing at birth.
• A flat or sunken tummy.
• The heart may be pushed to the wrong side.

How is it treated?

• Breathing support: Your baby will be put on a breathing machine.
• Other treatments: Medicines to help the lungs and heart work better. Sometimes a special machine (ECMO) is needed if the lungs are very weak.
• Surgery: Once stable, an operation is done to put the tummy contents back and close the hole.

Key Counselling Points

1. Serious Condition: "This is a serious condition. The main problem is that the lungs haven't developed fully."
2. Specialist Care: "Your baby will be cared for at a specialist centre with experts in this condition."
3. Outcome Varies: "Survival depends on how developed the lungs are. Most babies with isolated CDH have a good chance with modern treatment."
4. Long-Term Follow-Up: "Babies with CDH need follow-up for lung problems, feeding, and development."

• Vincent Bochdalek (1848): Czech anatomist who described the posterolateral diaphragmatic defect bearing his name.
• Giovanni Morgagni (1769): Italian anatomist who described the anterior (retrosternal) diaphragmatic hernia.
• Shift from Immediate Surgery (Pre-1990s): Previously surgery was performed immediately. Realisation that stabilisation first improves outcomes led to the modern "delayed repair" approach.
• ECMO (1980s-Present): Introduced as a rescue therapy. Has improved survival in severe cases.