Congenital megacolon

Definition

Hirschsprung's disease is a blockage of the large intestine due to improper muscle movement in the bowel. It is a congenital condition, which means it is present from birth.

Alternative Names

Causes

Muscle contractions in the gut help digested materials move through the intestine. This is called peristalsis. Nerves in between the muscle layers trigger the contractions.

In Hirschsprung's disease, the nerves are missing from a short or long part of the bowel. Areas without such nerves can not push material through. This causes a blockage. Intestinal contents build up behind the blockage, causing the bowel and abdomen to become swollen. If the condition is severe, the newborn may fail to pass meconium or stool, and the newborn may vomit.

Milder cases may not be diagnosed until a later age. In older children, the disease may be cause chronic constipation, abdominal swelling, and decreased growth.

Hirschsprung's disease causes about 25% of all newborn intestinal obstructions. It occurs 5 times more frequently in males than in females. Hirschsprung's disease is sometimes associated with other inherited or congenital conditions such as Down syndrome

Symptoms

• Failure to pass meconium shortly after birth
• Failure to pass a first stool within 24 - 48 hours after birth
• Constipation
• Abdominal distention
• Vomiting
• Watery diarrhea (in the newborn)
• Poor weight gain
• Slow growth (child 0-5 years)
• Malabsorption

Exams and Tests

During a physical examination, the doctor may be able to feel loops of bowel in the distended abdomen. A rectal examination may detect a loss of muscle tone in the rectal muscles.

Tests used in the diagnosis of Hirschsprung's disease include:

• Abdominal x-ray, showing distention of colon with gas and feces
• Barium enema
• Anal manometry (a balloon is dilated in the rectum to measure the anal sphincter pressure)
• Rectal biopsy, showing absence of ganglion nerve cells

Treatment

The abnormal section of colon must be surgically removed. Sometimes this can be accomplished with a single operation. However, it is frequently performed as a two-staged procedure with a colostomy being performed at the time of diagnosis, and a definitive procedure being performed later in the first year of life.

Outlook (Prognosis)

Symptoms are eliminated in 90% of children after surgical treatment. A better outcome is associated with early treatment, and shorter bowel segment involvement.

Possible Complications

• Perforation of the intestine
• Enterocolitis
• Short gut syndrome

When to Contact a Medical Professional

Call your child's health care provider if symptoms suggestive of Hirschsprung's disease develop.

Call your child's health care provider if abdominal pain or other new symptoms develop after treatment for Hirschsprung's disease.