Uncommon Causes of Constipation
Hirschsprung's disease is sometimes called congenital megacolon or congenital intestinal aganglionosis. This is a rare disorder that occurs in about 1 of every 5,000 to 10,000 newborn babies, and much more commonly in boys than girls. By comparison, constipation occurs in as many as 1 of every 5 to 10 children.
Hirschsprung's disease results when some of the nerves in the intestine (ganglion cells) don't develop normally. These nerves help the intestine to relax. In children with Hirschsprung's disease, the intestine is constantly squeezed tight, preventing stool from passing. Almost all these children have problems with constipation from the day they are born; almost half will not pass their first bowel movement during the first 36 hours of life.
We still don't know what causes Hirschsprung's disease. Genetics probably play a role, although most parents cannot identify anyone in their family with the disease. There is currently no evidence that Hirschsprung's disease is caused by any medication or exposure to toxins during pregnancy.
When there is concern about the possibility of Hirschsprung's disease, an x-ray procedure called a barium enema is usually done. A small tube is inserted into the baby's rectum and barium (an inert dye) is pumped into the lower intestine. The radiologist looks for an area of narrowing that suggets Hirschsprung's disease (picture at right).
If this narrowing is found, a rectal biopsy is usually performed, removing a small piece of the lower intestine and examining it under the microscope for the presence or absence of ganglion cells. If ganglion cells are present, the baby does not have Hirschsprung's disease.
Sometimes a painless test called anorectal manometry will also be done to measure whether the intestine is able to relax normally. Remember, in Hirschsprung's disease, the absence of nerves prevents the intestine from relaxing normally.
If a child has Hirschsprung's disease, some form of surgery is usually required to eliminate the problems with constipation.
Neurological Causes of Chronic Constipation
Many children who have problems with their nervous system may have constipation. It is not unusual for children with cerebral palsy, meningomyelocele, or muscular dystrophy to be constipated. In rare cases, constipation may be the first sign of an abnormality of the spinal cord. When this happens, there are almost always other signs such as poor coordination, weakness of the legs or feet, and/or difficulties with bladder control.
Hypothyroidism and Chronic Constipation
Many children with hypothyroidism have problems with constipation that go away once their hypothyroidism is treated. It would be extrememly unusual for constipation to be the only sign of thyroid problems. Most children with hypothyroidism would have other symptoms such as sluggishness, puffiness, low temperature, and low heart rate.