By Dr Saravana K.
It is a disease of the large intestine which results in a blockage of the intestine so that stool cannot pass through. Normally, muscles in the large intestine push stool to the anus, where stool leaves the body. The intestine’s ability to push and relax is enabled by nerve cells in the intestine called ganglion cells. A person with HD does not have these nerve cells in part of the large intestine, creating the problems associated with the disease. Sometimes these nerve cells are missing from only a few centimetres but they also can be missing from long segments of the large intestine and even parts of the small intestine.
The healthy muscles of the intestine push the stool until it reaches the rigid part of the intestine without the nerve cells. At this point, the stool stops moving. New stool then begins to collect behind it.
HD occurs in one out of every 5000 births, commoner in boys and is associated with Down’s syndrome. HD develops before a child is born. Normally, nerve cells grow in the baby’s intestine soon after the baby begins to develop in the womb. These nerve cells grow down from the top of the intestine all the way to the anus. With HD, the nerve cells stop growing before they reach the end.
It is unclear why the nerve cells stop growing.
Usually presents in very young children.
Could also be present in the teenage years or adult life.
Failure to pass contents of the fetal intestine shortly after birth
Failure to pass first stool within 24 to 48 hours after birth
Serious infection of the intestines called enterocolitis.
During physical examination, the doctor might be able to feel the abdomen and detect the area where the large intestine is obstructed and also be swollen. Tests done include:
Abdominal X-ray — looking for a bowel blockage.
During a rectal examination, the doctor will check the rectum for a lack or impaction of stool, as well as whether the anal canal feels narrowed.
Barium enema X-ray is a contrast liquid that makes the intestine show up on the X-ray. For this test, barium is inserted into the intestine through the anus and then X-rays are taken. In places where the nerve cells are missing, the intestine looks too narrow.
Manometry — A test used in older children where the doctor inserts a small balloon inside the rectum and then inflates it. Under normal circumstances, the anal muscle will relax. If it doesn’t, HD might be the cause.
A biopsy is the most accurate test for HD. The doctor removes a tiny piece of the intestinal lining and then looks at it under a microscope. If the nerve cells are missing, HD can be confirmed.
HD is treated with surgery to bypass the part of the colon that has no nerve cells. The lining of the diseased part of the colon is stripped away, and normal colon is pulled through the colon from the inside and attached to the anus.
After surgery, most children pass stool normally – although some may experience diarrhoea initially. Toilet training may take longer because children have to learn how to coordinate the muscles used to pass stool.