Hirschsprung disease

What it is

Hirschsprung disease is congenital aganglionic megacolon: ganglion cells are absent from the myenteric and submucosal plexuses of a segment of large bowel, and about 75% of cases sit in the rectosigmoid area. The aganglionic segment is narrow and contracted, peristalsis in it is absent or deficient, and the result is a functional intestinal obstruction. Constipation follows, with distention of the bowel proximal to the aganglionic area, and it is this chronically distended bowel that gave the disease the name megacolon.

Causes and risk

It is a congenital disorder of newborns. Boys are affected more than girls, the ratio being given as 3 to 1 in one place and 4 to 1 in another. It is common in Down syndrome; trisomy 21 and multiple endocrine neoplasia type 2 are the associated conditions named.

In the Down syndrome examination the abdomen carries three entries, and Hirschsprung disease is one of them: 1) duodenal stenosis or atresia, which gives the double bubble sign; 2) imperforate anus; 3) Hirschsprung disease. It is also the reason given for constipation in the history of a child with Down syndrome, beside developmental delay, feeding problems from duodenal atresia, obstructive sleep apnea, and the dyspnea, palpitations and respiratory distress of a congenital heart defect.