Congenital Aganglionic Megacolon - Hirschsprung Disease

Overview, Causes, & Risk Factors

Hirschsprung disease is a blockage in the large intestine. It is caused by an lack of nerve cells in a portion of the intestine. A person is born with this condition.

What is going on in the body?

A person with this disease is missing the nerve cells known as ganglia in part or all of the large bowel. These cells are absent at birth. The normal function of these cells is to enable the bowel muscle to contract. This motion pushes the stool through the intestine. Stool cannot pass through the segment of the bowel where the nerves are missing. As a result, stool collects at that point causing an intestinal blockage.

What are the causes and risks of the disease?

This disease is present at birth. It occurs because some nerve cells fail to develop in portions of the large bowel while the fetus is growing in the uterus. This disease may be inherited. Most of the time, however, the cause is unknown. It is more common in boys than girls. This disease may also be associated with other conditions that are present at birth such as Down syndrome.

Symptoms & Signs

What are the signs and symptoms of the disease?

Indications of this disease usually begin within a few days after birth.

Rarely, symptoms do not appear until childhood or even adulthood. In an infant, symptoms include:

not passing the first bowel movement, called meconium, within the first 24 to 48 hours after birth

difficulty having a bowel movement

watery stools if bowel movements do occur

swelling of the abdomen

vomiting

rapid breathing as the disease progresses

irritability

In older children symptoms include:

passing small, ribbon-like, or watery stools. Stools are passed only rarely.

chronic constipation

lack of appetite

poor weight gain

decreased rate of growth

Diagnosis & Tests

How is the disease diagnosed?

The healthcare provider will first do a physical exam. Abdominal swelling may be present. There may not be any fecal material in the anal canal or rectum. These are the areas in which stool is stored before it leaves the body. Also, there may be a gush of pale, liquid stool and gas as the healthcare provider withdraws a finger after performing the rectal exam. Other tests are done to confirm the diagnosis. These may include:

rectal manometry. This test records pressure changes within the colon and rectum. It is used to evaluate how the bowel contracts and relaxes.

barium enema, an x-ray exam of the colon and rectum

a rectal biopsy. In this procedure, a small piece of bowel tissue is removed. The tissue is examined under a microscope to see if nerve cells are present.

Prevention & Expectations

What can be done to prevent the disease?

This disease cannot be prevented. If a person has this disease, genetic counseling may be useful in understanding how the disease may be passed on to children.

What are the long-term effects of the disease?

Severely affected infants will die without treatment. Other long-term effects include a possible perforation of the intestine, and infection or inflammation of the intestines and colon. These, too, may lead to death. Treatment helps to prevent these complications.

What are the risks to others?

This disease is not contagious. It can be inherited in some cases. Genetic counseling may be useful for family members of children with this disease.

Treatment & Monitoring

What are the treatments for the disease?

Most people with this disease will need surgery. Usually, the affected part of the bowel is removed. Surgery is often a two-part process. A procedure called a colostomy often the first step. During the colostomy, the bowel is divided and the affected portion removed. The surgeon then creates a hole in the skin of the abdomen, known as a stoma. The top part of the bowel is connected to the stoma. Stool can then leave the body through this opening while the lower part of the bowel heals. Once the lower bowel has healed, a second surgery can be done to reconnect it to the rest of the intestine. The stoma will then be closed and normal bowel movements should resume. Fluids may be given through a vein during and after surgery. Antibiotics may also be administered to prevent or treat infection in the bowels.

What are the side effects of the treatments?

Any surgery has possible side effects. These may include bleeding, infection, and allergic reactions to pain medications. If antibiotics are used, they may cause stomach upset or allergic reactions. Some people experience involuntary loss of stool after the surgery.

What happens after treatment for the disease?

After surgery, symptoms usually go away. Most children are able to have normal bowel movements after surgery. In general, the earlier a person receives treatment, the better the outcome.

How is the disease monitored?

The child's caregiver should contact a healthcare provider right away if new or worsening symptoms occur after surgery.