Hirschsprung's disease

Alternative names:

congenital megacolon

Definition:

An obstruction of the large intestine caused by inadequate motility (muscular movement of the bowel) that occurs as a congenital condition.

Causes, incidence, and risk factors:

Congenital megacolon is cause by the absence of nerves cells (called ganglia cells) in the large intestine which stimulate the rhythmic contraction which moves material through the gut (peristalsis). These ganglia cells may be absent from only a short segment of large intestine or they may be absent from all of it. Segments in which there is no peristalsis will not pass any bowel content beyond that point. The end result is that the bowel, although open, can not move material and is effectively obstructed.

Accumulation of intestinal contents behind the obstruction causes distention of the bowel and abdomen. If the condition is severe, symptoms may occur in the newborn with failure to pass meconium, failure to pass stool, abdominal distention, and vomiting. Milder cases may not be diagnosed until a later age. In older children they may be characterized by chronic constipation, abdominal distention, and decreased growth rate.

Hirschsprung's disease causes one fourth of all newborn intestinal obstruction, but the condition may not be detected until later in infancy or childhood. It occurs 5 times more often in males than in females. Hirschsprung's disease is sometimes associated with other inherited or congenital conditions such as Down syndrome.