A nine-month-old girl was brought with complaints of recurrent upper respiratory tract infection since the age of two months. She had history of regurgitation after feeds.

RADIOLOGICAL FINDINGS:

Plain radiographs of the chest revealed a well-defined soft tissue opacity in the right lower zone in the paracardiac region. Laterally, the margin of the soft tissue opacity could be traced upto the hilum. Inferiorly, the lesion seemed to extend beyond the diaphragm. The thoraco-abdominal sign was positive and the medial border of the opacity could not be well delineated. The right border of heart could be seen well through the soft tissue opacity which was thus interpreted to be posterior placed possibly arising from below the diaphragm.

Fig. 1	Fig. 2

A CT scan revealed herniation of the stomach posterior to the heart in the right paraspinal region.

Fig. 3	Fig. 4

A barium study confirmed the diagnosis of herniation of stomach into the thoracic cavity posterior to the heart on the right side.

Fig. 5	Fig. 6

DISCUSSION:

A congenital diaphragmatic hernia (CDH) is a displacement of abdominal contents into the thoracic cavity through a defect in the diaphragm. Riverius, who incidentally noted a CDH during a postmortem examination of a 24 year old person, first described CDH in 1679.

CDH occurs 1 in every 2000-4000 live births and accounts for 8% of all major congenital anomalies.

Benjamin et al reported a male preponderance in left-sided hernias - with a male-to-female ratio of 3:2. The incidence is even more striking in right-sided hernias, with a male-to-female ratio of 3:1. The risk of recurrence of isolated CDH for future siblings is approximately 2%.

Age: While CDH is most commonly a disorder of the newborn period, as many as 10% of patients may present after the newborn period and even during adulthood. Outcome in patients with late presentation of CDH is extremely good with low or no mortality.

Pathophysiology:

The three basic types of CDH are the posterolateral Bochdalek hernia (occurring at approximately 6 weeks' gestation), the anterior Morgagni hernia, and the hiatus hernia. The left-sided Bochdalek hernia occurs in approximately 90% of cases. Left-sided hernias allow herniation of both small and large bowel as well as intra-abdominal solid organs into the thoracic cavity. In right-sided hernias, only the liver and a portion of the large bowel tend to herniate. Bilateral hernias are uncommon and usually fatal. The major problem in a Bochdalek hernia is the posterolateral defect of the diaphragm which results in either the failure of the pleuro-peritoneal folds to develop or the improper or absent migration of the diaphragmatic musculature. Bilateral Bochdalek hernias are rare.

The Morgagni hernia is a less-common CDH, occurring in only 5-10% of cases of CDH. This hernia occurs in the anterior midline through the sternocostal hiatus of the diaphragm, with 90% of cases occurring on the right side.

CDH is characterized by a variable degree of pulmonary hypoplasia associated with a decrease in the cross-sectional area of the pulmonary vasculature and dysfunction of the surfactant system.

Associations: De Lange syndrome, Fryns syndrome, Trisomy 13, Trisomy 18

Clinical presentation:

Infants may have an antenatal history of polyhydramnios. Infants most commonly present with a history of cyanosis and respiratory distress in the first minutes or hours of life - although a later presentation is possible. Frequently, infants exhibit a scaphoid abdomen, respiratory distress and cyanosis. In left-sided posterolateral hernias, auscultation of the lungs reveals poor air entry on the left with a shift of cardiac sounds over the right chest.

Morgagni hernias are usually asymptomatic in the infant.

Imaging:

Antenatal USG- In patients presenting in the prenatal period, ultrasonographic features indicative of CDH include the following: polyhydramnios; an absent or intrathoracic stomach bubble; mediastinal and cardiac shift away from the side of the herniation.

Chest radiograph - Typical findings in left-sided posterolateral CDH include air or fluid-filled loops of the bowel in the left hemithorax and shift of the cardiac silhouette to the right.

CT scan usually reveals retroperitoneal fat, kidney and bowel loops herniating through the defect.

Barium studies reveals herniation of bowel loops, stomach through the defect.

Treatment:

Until recently, specialists believed that reduction of the herniated viscera and closure of the diaphragmatic defect should be performed emergently following birth. More recent research demonstrates that a delayed surgical approach that enables preoperative stabilization decreases morbidity and mortality. This change is due to the recent understanding that pulmonary hypoplasia, PPHN, and surfactant deficiency are largely responsible for the outcome of CDH and that the severity of these pathophysiologies is largely predetermined in utero. The pathophysiology does not appear to be exacerbated postnatally by herniated viscera in the chest as long as bowel decompression is continuous using a nasogastric tube.