The diaphragm is the muscular sheath that separates the organs of the chest from those of the abdomen.
Diaphragmatic hernias occur on the left side of the body 85% of the time. The stomach, loops of intestine, and even the liver and spleen can protrude through the hernia. If the hernia is large, the lung on the affected side is usually incompletely developed, but the lung on the opposite side also can be affected. About half of children with diaphragmatic hernias also have heart defects, kidney defects, or chromosome disorders.
After delivery, as the newborn cries and breathes, the loops of intestine quickly fill with air. This rapidly enlarging structure pushes against the heart, compressing the other lung and causing severe difficulty breathing, often right after birth. Also, if the lung had been compressed a lot before birth, the blood vessels in the lung become narrowed, which causes high blood pressure in the lung arteries (persistent pulmonary hypertension). The high blood pressure does not let enough blood flow through the lungs, which limits the amount of oxygen in the bloodstream. Persistent pulmonary hypertension is the major cause of death among infants who are born with diaphragmatic hernia.
(See also Overview of Digestive Tract Birth Defects.)
Measures to deliver oxygen, such as a breathing tube and ventilator (a machine that helps air get in and out of the lungs), may be needed.
Surgery is required to repair the diaphragm.