Hirschsprung's Disease - Short-Segment and Long-Segment HD
Hirschsprung’s disease (HD) is a congenital disease of the large intestine that causes constipation in infants and young children.
Under normal circumstances, muscle contractions move food through the large intestine (also called the colon). Those muscle contractions are controlled by nerve cells that sense food within the colon. In Hirschsprung’s disease, those nerve cells are absent from the colon. A term to describe this kind of missing nerve cells is aganglia. As a result of the disease, food becomes stuck and blocks the colon, worsening the constipation.
HD is present from birth and affects roughly 1 out of 5,000 children born. It is five times more common in boys. The disease varies in severity depending on how much of the colon is affected.
In the more common short-segment HD, nerves cells are absent only in the last segment of the colon.
In long-segment HD, meanwhile, most of the colon is affected.
In some cases (total colonic aganglionosis), parts of the small intestine are also affected, although this is rare.
Most infants are diagnosed during the first few days after birth because they are unable to pass meconium (newborn stool). Mild cases of Hirschsprung’s disease may be diagnosed at a later age. HD treatment involves removing/bypassing the diseased portion of the colon in order to achieve normal bowel movement. Most children with HD respond well to treatment and live normal adult lives.
Causes and Risk Factors
Hirschsprung’s disease is caused by a defect in the migration of nerve cells along the developing colon. This developmental arrest occurs between 5 and 12 weeks of gestation (fetal development in the womb) for reasons that are not fully understood. Normally, the bundles of nerve cells called ganglia constitute the enteric nervous system, which lines the gastrointestinal tract and regulates the movement of content entering the body (as food) and exiting the body (as stool). Without the proper nerve signals, the muscles that push feces through the colon and towards the anus are in effect paralyzed. The risk factors for HD include:
Family history. Some genetic factors have been associated with HD. Therefore, having one child with HD increases the likelihood that other offspring will also have the condition.
Other inherited/genetic conditions. HD has been linked to other inherited or chromosomal diseases, such as Down syndrome.
Gender. For reasons that are not known, HD is five times more prevalent in boys.
Symptoms of Hirschsprung’s Disease
HD symptoms are highly dependent on disease severity. In a newborn, the inability to pass stool within 48 hours of birth is an indication of HD. If Hirschsprung’s disease is only present in a small percentage of the colon, symptoms may not appear until an older age.
Newborn symptoms include:
Not having a bowel movement within 48 hours of birth
Difficulty passing stool
Delayed symptoms in toddlers/older children include:
Poor weigh gain
Lack of energy.
If doctors suspect Hirschsprung’s disease, various tests are performed to examine the colon.
Manual exam. The doctor may press on the belly to feel for bulges associated with impacted stool. A digital rectal exam may also be performed, where a gloved finger is inserted into the rectum.
X-ray. The combination of X-ray and a contrast agent (barium) allows for visual inspection of the abdominal region. On a typical X-ray image showing HD, a normal functioning proximal colon appears swollen in comparison to the affected distal colon.
Manometry. Anal manometry looks at muscle conditioning within the colon. This test measures the amount of pressure exerted by the colon onto a balloon that is inserted into the colon.
Biopsy. A tissue sample collected from the colon may be examined under the microscope. Nerves will be absent in samples from areas affected by HD.
Treatment and Prevention
Surgical removal of the diseased colon and rerouting of the healthy colon to the anus is the most common treatment for Hirschsprung’s disease. Most patients recover fully and achieve normal bowel movement through adulthood. Following surgery, children may continue to experience some symptoms and, depending on age, face challenges during toilet training. The risk of infection is also high following surgery. Without treatment, severe inflammation, infection (enterocolitis) and perforation may occur inside the intestines.
Pull-through. This surgical procedure involves removing the diseased portion of the colon and connecting the healthy proximal colon segment directly to the anus.
Ostomy. With infants or patients with severe HD, an ostomy is performed first. Once the child has reached age 1 or shows improvement in symptoms, then the pull-through procedure is carried out. With a colostomy, part of the colon is removed, while an ileostomy allows for removal of the entire colon. The healthy portion of the colon is then connected to an opening on the abdomen to form a stoma. The stoma becomes the new exit route for waste, which is collected into a pouch on the outside. The opening in the abdomen is closed later when the intestine is connected to the anus.
At-home remedies. Regular exercise and a healthy, high-fiber diet of good fats, whole grains, fruits and vegetables help relieve/prevent constipation following surgery. With some or all of the colon removed, the body absorbs less water and can easily become dehydrated; extra fluid intake helps keep the body hydrated. Infants on formula who experience constipation may benefit from changing the brand of formula.
Hirschsprung’s disease is an inherited congenital disease with no means of prevention. Parents of children with HD can avoid serious complications by ensuring early diagnosis and treatment.
“Hirschsprung’s disease”. Mayo Clinic Foundation. Retrieved Apr 28, 2015. http://www.mayoclinic.org/diseases-conditions/hirschsprungs-disease/basics/definition/con-20027602.
“Hirschsprung’s disease”. The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Retrieved Apr 28, 2015. http://www.niddk.nih.gov/health-information/health-topics/digestive-diseases/hirschsprung-disease/Pages/ez.aspx#1.
Amiel J, Sproat-Emison E, et al. “Hirschsprung disease, associated syndromes and genetics: a review.” J Med Genet. 2008, 45(1):1-14. Review.