Congenital megacolon

Alternative names
Hirschsprung’s disease

Definition
Hirschsprung’s disease is an obstruction of the large intestine caused by inadequate motility (muscular movement of the bowel) that occurs as a congenital (present at birth) condition.

Causes, incidence, and risk factors

Digested matter normally passes through the intestine as a result of the rhythmic contraction of the muscles that line the gut (peristalsis). These muscles are stimulated to contract by nerve bundles, called ganglia, located between the muscle layers.

In Hirschsprung’s disease, the ganglia are missing, usually from only a few centimeters of bowel, but sometimes from long segments of bowel. Segments in which there is no peristalsis will not pass any digested matter beyond that point. The end result is that the bowel cannot push material through and is effectively obstructed.

Intestinal contents accumulate behind the obstruction, thus causing the bowel and abdomen to become distended. 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 characterized by chronic constipation, abdominal distention, and decreased growth rate.

Hirschsprung’s disease causes one fourth of all newborn intestinal obstruction, but the condition may not be detected until later in infancy or childhood. It occurs five 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 to 48 hours after birth  
  • constipation  
  • abdominal distention  
  • vomiting  
  • watery diarrhea (in the newborn)  
  • poor weight gain  
  • slow growth (child 0-5 years)  
  • malabsorption

Signs 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

Most cases require surgery. A temporary colostomy (an opening from the bowel to the abdominal wall) is performed as soon as possible to prevent complications associated with bowel obstruction.

Removal of the affected bowel segment and reconnection of the colon is usually performed when the infant is 6 months or older. Antibiotics are given if a hole in the bowel (perforation) or enterocolitis has occurred.

Expectations (prognosis)

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

Complications

     
  • perforation of the intestine  
  • enterocolitis  
  • short gut syndrome

Calling your health care provider

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.

Johns Hopkins patient information

Last revised: December 8, 2012
by Armen E. Martirosyan, M.D.

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