Congenital Diaphragmatic Hernia: Causes, Symptoms, Management

Posted on Mar 31, 2025 in Biology

Congenital Diaphragmatic Hernia

Anatomic Lung Alterations

  • Failure of the Bochdalek foramen of the diaphragm to close.
  • Migration of the intestines into the thorax.
  • Atelectasis.
  • Complete lung collapse.
  • Mediastinal shift to the unaffected side of the thorax.
  • Reduction in the number of bronchial generations and alveoli per acinus.

Etiology

A congenital diaphragmatic hernia (CDH) occurs in approximately 1 out of 2,000 to 4,000 live births. The baby is usually mature at birth. Two-thirds of affected infants are males. About 95% of cases occur on the left side through the Bochdalek foramen. The mortality rate is about 40%. The prognosis depends on several factors:

  • Size of the defect
  • Degree of pulmonary hypoplasia
  • Condition of the lung on the unaffected side
  • Success of the surgical diaphragmatic closure

Cardiopulmonary Manifestations

A key manifestation is atelectasis.

Physical Examination: Vital Signs

Observe for:

  • Increased Respiratory Rate (Tachypnea): A newborn infant’s respiratory rate (RR) is normally about 40 to 60 breaths per minute (b/m). When a diaphragmatic hernia is present, the RR is generally well over 60 b/m.
  • Increased Heart Rate (Tachycardia): Heart rate (HR) is typically elevated.
  • Increased Blood Pressure: Hypertension may be present.

Manifestations of Negative Intrapleural Pressure

  • Intercostal retractions
  • Substernal retractions
  • Cyanosis of the dependent portion of the thoracic and abdominal area
  • Flaring nostrils

Chest Assessment Findings

  • Diminished or absent breath sounds over the affected side.
  • Bowel sounds heard over the affected side.
  • Apical heartbeat heard over the unaffected side (usually the right).
  • Expiratory grunting.
  • Cyanosis.
  • Barrel chest.
  • Scaphoid abdomen (sunken appearance).

Chest Radiograph Findings

A typical chest radiograph shows:

  • Fluid and air-filled loops of intestine in the chest.
  • A shift of the heart and mediastinum to the unaffected side.
  • Atelectasis and complete lung collapse may be present.
  • Lungs may appear hypoplastic and may not expand to meet the chest wall.
  • A nasogastric (NG) tube (hopefully positioned in the patient’s stomach) may be visible; it is used to decompress the abdominal viscera.

The presence of a diaphragmatic hernia on a chest X-ray film usually confirms the need for surgery.

General Management

Severe diaphragmatic hernia is one of the most urgent neonatal surgical emergencies. The following therapeutic measures may be instituted until the baby is stabilized for surgery:

  • Insertion of a double-lumen orogastric tube with intermittent or low continuous suction.
  • Oxygen therapy.
  • Place the infant in the semi-Fowler’s position.
  • Position the infant on the affected side.
  • Avoid manual ventilation with a bag and mask.
  • Intubation and mechanical ventilation may be necessary. Mechanical ventilation should use low peak pressures (<30 cmH₂O) and rapid respiratory rates.
  • A typical set of initial ventilator parameters might be:
    • PIP: 18-20 cmH₂O
    • RR: 40 breaths/min
    • FiO₂: 100%
    • PEEP: 2 to 3 cmH₂O
    • Inspiratory Time (IT): 0.4 seconds
  • High-frequency oscillatory ventilation (HFOV) and jet ventilation are sometimes successful.
  • Due to the high incidence of pneumothorax, one or more chest tubes may be necessary during mechanical ventilation.
  • Paralysis (e.g., with pancuronium) and sedation (e.g., with morphine) are sometimes helpful.
  • Extracorporeal membrane oxygenation (ECMO) is commonly applied to stabilize the infant prior to surgery. While on ECMO, the infant might be ventilated minimally (e.g., 3 to 4 times per minute) to keep the lungs inflated.

Post-Surgery Management:

  • After surgery, the infant is placed back on the ventilator and managed according to protocol.
  • PEEP and CPAP are commonly required to offset atelectasis.
  • Pharmacologic agents may be used to manage pulmonary hypertension:
    • Tolazoline
    • Digitalis agents
    • Diuretics
    • Nitroglycerin
    • Inhaled Nitric Oxide (iNO)
  • ECMO may be indicated to treat circulatory and respiratory complications after surgery.
  • Pulmonary surfactant is usually administered to support the infant’s immature and hypoplastic lungs.