In this not uncommon disease, the parasympathetic plexi of a child's rectum and distal colon do not develop normally, so that his faeces are not propelled onwards as they should be. The length of the aganglionic segment varies, and may stretch from his upper rectum, to half-way along his transverse colon. He becomes constipated, and his abdomen distends; and in acute cases his gut may obstruct. He may present at any time during childhood in any of the following ways:
HIRSCHSPRUNG'S DISEASE If a child presents soon after birth with subacute obstruction, its onset is more gradual than with complete mechanical obstruction, but it is still fairly acute. Rectal examination is normal. X-rays show fluid levels and an upside- down X-ray shows air as far as his anus. His distal large gut may look narrow. Do a transverse colostomy, as for a high rectal malformation (28.6), and refer him.
If he presents later, during the first three years, with abdominal distension, and his condition is not acute (usual), refer him for resection of the diseased segment. If it is acute (very unusual), and if it is essential for his health, do a transverse colostomy before referring him.
If he presents up to the age of 10 years as ''a child whose abdomen is large and who does not open his bowels easily', refer him. The surgeon will have to distinguish Hirschsprung's disease from ''chronic constipation', by doing a biopsy which includes the submucosa, and with it the faulty plexi. At operation, he will have to decide where the faulty plexi end, excise the diseased segment, and anastomose the colon to the distal rectum.