A congenital diaphragmatic hernia (CDH) is a serious condition present at birth, where an opening in the diaphragm allows abdominal organs like the intestines, stomach, or liver to move into the chest cavity. While a significant medical challenge, advancements in care have made it a treatable condition. Understanding this condition is an important first step for parents.
Understanding Diaphragmatic Hernia
A congenital diaphragmatic hernia (CDH) is a defect in the diaphragm, the dome-shaped muscle separating the chest from the abdominal cavity. This allows abdominal organs like the intestines, stomach, spleen, or liver to move into the chest. The most common type is a Bochdalek hernia, located on the left side and accounting for over 95% of cases.
The presence of abdominal organs in the chest limits room for the developing lungs, leading to pulmonary hypoplasia, where the lungs are smaller and less developed. This displacement also affects blood vessels within the lungs, which may not form correctly, contributing to high blood pressure in the lung arteries, known as pulmonary hypertension. Both pulmonary hypoplasia and pulmonary hypertension are factors contributing to breathing difficulties after birth.
The precise cause of CDH is often idiopathic, understood as a developmental issue occurring early in pregnancy, between the 4th and 8th week of gestation, when the diaphragm fails to close completely. In 10-15% of cases, CDH can be associated with genetic factors, such as chromosomal abnormalities, specific gene mutations, or other syndromes.
Recognizing the Signs and Diagnosis
Many CDH cases are identified before birth during routine prenatal ultrasound examinations, around 20 weeks of gestation. Sonographers look for specific indicators, such as abdominal organs, including the stomach or intestines, within the chest cavity, and a shift of the heart from its normal position. The fetal lung size relative to head circumference, known as the lung-to-head ratio (LHR), is also assessed to predict lung underdevelopment severity. A low LHR, less than 25%, suggests a more severe condition.
For newborns not diagnosed prenatally, signs appear shortly after birth, especially in severe cases. These signs include severe breathing difficulties, characterized by rapid breathing, grunting sounds, and a bluish discoloration of the skin, known as cyanosis. The baby’s abdomen might appear caved in or “scaphoid” because abdominal contents have moved into the chest, and breath sounds may be diminished or absent on the affected side.
A chest X-ray is the primary tool to confirm diagnosis after birth. X-ray images show loops of bowel or other abdominal organs in the chest cavity, a mediastinal shift where the heart and other structures are pushed to the opposite side, and a reduced volume of the affected lung. Further tests, such as an echocardiogram, may be performed to assess heart function and pulmonary hypertension.
Treatment and Immediate Care
Immediate post-birth stabilization is a priority for newborns diagnosed with CDH. The medical team prioritizes respiratory support, involving endotracheal intubation to assist underdeveloped lungs. Bag-mask ventilation is avoided because it can introduce air into the stomach and intestines, causing them to distend and further compress the compromised lungs. A tube is inserted into the baby’s nose or mouth and threaded into the stomach to keep it empty, providing more space for the lungs.
Once the baby is stabilized and their physiological condition is optimized, surgical repair addresses the hernia. The timing of surgery is individualized, often delayed for several days after birth to allow the baby’s condition to improve. During the procedure, abdominal organs are repositioned back into the abdomen, and the hole in the diaphragm is closed, sometimes using a patch or mesh for larger defects. Delaying surgery until the baby is stable is a common approach.
In severe CDH cases, where conventional respiratory support is insufficient, Extracorporeal Membrane Oxygenation (ECMO) may be utilized. ECMO acts as a temporary heart and lung bypass system, allowing these organs to rest and recover while a machine oxygenates the blood and removes carbon dioxide. Babies on ECMO require this support for a period of time.
Following surgical repair, post-operative care is necessary. This includes continued respiratory support with mechanical ventilation to ensure adequate oxygenation and carbon dioxide removal. Pain management is provided, and nutritional support is initiated, which may involve intravenous fluids or tube feedings, as feeding difficulties are common. The medical team monitors the baby’s progress, including lung function, blood pressure, and overall stability.
Life Beyond Surgery and Long-Term Care
The prognosis for infants with CDH has improved over the past decades, with national survival rates now ranging from 65% to 70%, and even higher in specialized centers. However, outcomes can vary based on factors such as lung underdevelopment severity and the presence of other associated conditions.
Despite improved survival, many CDH survivors may experience long-term complications. Chronic lung disease is a common issue, requiring ongoing respiratory support or oxygen at home. Gastroesophageal reflux disease (GERD), where stomach acid flows back into the esophagus, and feeding difficulties are also observed. Some children may face developmental delays, such as motor and speech delays, and sensorineural hearing loss has also been noted.
Hernia recurrence is a possibility, occurring months to years after the initial repair. Orthopedic issues, such as chest wall deformities or scoliosis, can also develop. Ongoing monitoring is needed for these long-term health considerations.
Multidisciplinary follow-up care is recommended for CDH survivors, extending through childhood and into adolescence. This comprehensive care involves various specialists:
- Pulmonologists for lung health
- Gastroenterologists for digestive issues
- Nutritionists for growth support
- Developmental pediatricians to address any developmental delays
Families can also find support through various organizations dedicated to CDH, offering resources, information, and a community for those navigating this journey.