Hirschsprung disease: Hirschsprung's disease; Aganglionosis

Hirschsprung's disease (HD) affects 1 in 4,500 live births throughout the world. In the United Kingdom this equates to about one hundred and fifty to two hundred new cases of HD each year.

HD affects the nerves of the large intestine (colon). The main function of the colon is to conserve water and salt, to store faecal material (stool), and to regulate its release from the body. Normally, special nerve cells (ganglion cells) control the pushing movement of muscles in the colon and push stool to the anus where it is expelled from the body. In HD, ganglion cells can be missing (aganglionosis) from any part of the colon. As a result the colon becomes narrowed and unable to function. Stool will then build up behind the narrowed segment and that part of the colon becomes chronically distended, giving rise to the name 'megacolon.' Usually, a ring of muscles just inside the body (internal anal sphincter) automatically relaxes to allow stool to pass from the body. In HD the internal anal sphincter becomes permanently contracted and so stool either passes through with great difficulty or not at all.

The length of colon affected can vary from child to child. Short segment HD involves up to a third of the large intestine and long segment HD involves more than one third, often the whole colon. Seventy per cent of individuals have short segment HD. The severity of the symptoms is not always consistent with the length of the intestinal segment involved but children with the whole colon involved tend to have more severe symptoms.

In most patients, HD presents during the first few days of life. The major symptoms of HD in a newborn baby are delayed first bowel movement (meconium stools), abdominal distension, chronic constipation, and reluctance to feed. Babies with HD may grow and develop more slowly than other babies (failure to thrive). Older children may experience constipation alternating with bouts of diarrhoea, vomiting, pain and anaemia (a shortage of red blood cells) due to blood being lost in the stool, so-called enterocolitis. When HD becomes apparent during adolescence and adulthood (acquired HD), constipation and anaemia are characteristic symptoms. Acquired HD may be associated with diseases such as Parkinson's disease, scleroderma, intestinal pseudo-obstruction, Chagas disease and drug induced or idiopathic (cause unknown) constipation.

Currently, HD diagnosis is confirmed with a rectal biopsy. This involves taking a small biopsy from the wall of the last part of the large bowel (rectum) to confirm the absence of ganglion nerves.

If HD is not treated, stool can fill the large intestine causing problems such as infection, bursting of the colon and sometimes death. Individuals diagnosed with HD, therefore, require immediate surgery. A number of procedures have been developed and vary depending upon on the extent of the involvement of the colon, the age of the patient, the severity of the symptoms and presence of enterocolitis. In the majority, surgery essentially involves removal of the aganglionic segment and rejoining of the remaining bowel. This is effective in relieving the obstruction caused by HD and most children with HD may lead near normal lives thereafter. Drug therapy is not effective.

Inheritance patterns
HD develops in children before they are born and is due to genetic factors. It is not caused by anything the mother did while pregnant. HD is a familiar disease, but is not inherited as a simple Mendelian trait.

Prenatal diagnosis
None at present.

Medical text written January 2003 by Contact a Family. Approved January 2003 by Professor P Milla, Professor of Paediatric Gastroenteritis and Nutrition, Great Ormond Street Hospital, London, UK. Last updated November 2006 by Dr Nikhil Thapar, Clinician Scientist and Honorary Consultant in Paediatric Gastroenterology and Nutrition, Great Ormond Street Hospital, London, UK.

Support for families of children with Hirschsprung disease can be obtained from Tummy Trouble.