Hirschsprung's Disease (also called congenital megacolon, congenital intestinal aganglionosis or aganglionic megacolon)
Hirschsprung's disease (HURSH-sproongz . duh-zeez) is a congenital condition where the large intestine (rectal area) lacks a kind of nerve cell called ganglion cells. Most babies (80%) have just a short segment of bowel affected, termed “short segment disease”. Other babies (about 15% of those with Hirschprung's disease) have a larger section of colon that lacks these special cells, and that affected bowel is located higher up in the colon (long-segment disease). A few babies (perhaps 5%) will lack these cells in their entire large intestine (called aganglionosis).
During fetal life a particular type of cell from the parasympathetic nervous system fails to migrate to the bowel, and thus the affected area has only sympathetic nerves in that area. The sympathetic nerves cause contraction of the bowel, and since they lack the parasympathetic system that has the opposite effect, the bowel does not relax to allow stool to pass through. This results in a narrow and contracted bowel segment with a large amount of stool dilating the bowel ahead of the narrowing (the enlarged area is called megacolon). Most babies (at least 50%) with Hirschprung's disease are diagnosed in the first 48 hours of life because they do not pass meconium (the first stool after birth, dark and sticky in consistency) and have abdominal distention. However, other infants with a milder form of the condition (partial innervation of the segment resulting in only a partial blockage) have constipation, vomiting, abdominal pain and distention, and sometimes, anemia, and they will be diagnosed in the first 2 months of life because of those symptoms. Rarely, Hirschsprung's disease is diagnosed later in childhood or adulthood following a life-long constipation problem.
Hirschsprung's disease occurs in 1 of 5000 live births and accounts for 20% of neonatal bowel obstructions. The most common type is three to four times more common in boys than girls. A family history can be traced in 7% of cases. There is a mortality rate of 20-25%. Children with Down syndrome (Trisomy 21) have a 3-10% risk of also being affected with Hirschsprung's disease.
Common Associated Symptoms
In the newborn period acute intestinal obstruction with bilious vomiting can become life-threatening. Infection can develop and spread throughout the system causing severe symptoms.
In less severe cases where Hirschsprung's disease is not promptly diagnosed, the baby will typically have irritability, poor growth and difficulty with feeding (called failure to thrive) as well as chronic constipation.
Short-term Treatment and Outcomes
Typically emergency surgery will be done to bring a healthy loop of bowel to the surface and create an opening in the skin for bowel contents to drain. This is called a temporary colostomy and it is necessary to allow the bowel to decompress and heal. At the time of surgery, many tiny samples of tissue will be collected from numerous places in the bowel and examined under the microscope to look for ganglionic cells. The location and number of ganglionic cells will pinpoint just where the affected bowel is located so that it can be removed in a second stage procedure. Once the child gains weight (typically in 3-5 months) the affected bowel is removed in a second-stage surgery. The colostomy will be closed and normal bowel will be connected to the rectum.
Children who are healthy and growing well at diagnosis and who have only a small segment of bowel affected may be able to have a one-stage surgical repair called a pull-through procedure. There are several different types of surgical procedures that can be performed, depending on the age of the child and the bowel segment affected.
Long-term Treatment and Outcomes
The majority of children have a very good outcome from the surgery and will develop normal bowel function. However, in some cases, even after successful surgery there may be ongoing problems with defecation and incontinence. Long-term follow-up with a gastrointestinal specialist will be very important, and growth will need to be carefully monitored.
Necrotizing enterocolitis (also called acute bacterial enterocolitis) is a severe complication where the bowel tissue dies because of inflammation and lack of blood supply. The mortality rate of this serious complication is 20-25%. Post-operative complications may also include anal stenosis (scarring and tightening, requiring dilatation to correct), fecal incontinence due to lack of sphincter tone, prolapse of the bowel, and perianal abscesses. Enterocolitis can also occur as a later complication, presenting with diarrhea due to inflammation of the bowel.
Implications for Children's Development
Except in children with Down syndrome, Hirschprung's disease should not have a global effect on the child's overall development if it is quickly diagnosed and treated. However, if it is not diagnosed early in life, the prolonged failure to thrive could affect growth as well as limit the child's general well-being due to poor nutrition. It is especially important for children to have excellent nutrition in the first years of life when the brain is growing rapidly.
Multiple surgeries can be difficult for the child and family. Complications of fecal soiling or constipation (occurring in perhaps 10% of children) can be very difficult for the child and family and may affect the child's life and social development. A school nurse might be very helpful to the child and family in setting up a school schedule that allows for frequent toileting with privacy for the child.
For more information, including resources for parents and general information about Hirschsprung’s disease, visit the following websites:
- American Pediatric Surgical Association
- National Digestive Diseases Information Clearinghouse (NDDIC)
- National Organization for Rare Diseases (NORD)
- The Mayo Clinic