People with Hirschsprung's disease have a lack of nerve cells in a part of the large intestine. These nerve cells are responsible for relaying a message from the brain to the muscles in the large intestine, signaling the colon to move food through the intestine. The area missing nerve cells is usually 1 to 2 feet in length and the bowel movement may become stalled in that area, causing that section of colon to become enlarged. This condition is often diagnosed soon after birth, but milder cases may not be discovered for years. The U.S. National Library of Medicine reports that Hirschsprung's disease is much more common in males.
X-ray
After a physical examination in which the physician attempts to feel distended loops of intestine in the abdomen, an X-ray of the abdominal area may be taken. She is looking for enlarged sections of large intestine (above the problem area) or sections of small intestine that are enlarged from a back-up of stool. Stool may be absent from the lower part of the colon, near the rectum. Mayo Clinic explains that the physician may also note a decreased amount of air in the large intestine, indicating that the stool is backing up.
Manometry
The physician may feel the inside of the rectum with her fingers to learn if it has an appropriate muscle tone. She may perform a manometry procedure by inflating a small balloon inside the rectum. Normally, the anal musculature will relax in response to the balloon. This measurement of the pressure inside the rectum during the procedure may indicate Hirschsprung's disease. Manometry is normally not performed on infants.
Diagnostic Enema
If the physician needs to see the entire colon, he may order a diagnostic enema. In this procedure, barium or another liquid is administered into the bowel through the rectum. Air may also be added. The colon can now be visualized more clearly under X-ray; Hirshsprung's disease will appear as a narrowed or blocked portion of the colon with enlargement further up the intestine as stool collects above the narrowing. He may order a follow-up X-ray for the next day, to see if the barium is still present in the intestine.
Biopsy
A biopsy may be performed by suctioning a small amount of tissue from the lining of the intestine. This is accomplished by inserting a small device through the rectum. The tissue is evaluated to determine if unusual cells found in Hirschsprung's are present and the normal nerve cells are absent. If this is the case, a larger tissue sample is obtained---either by suction or minor surgery---and evaluated to confirm the diagnosis.
