(Congenital Megacolon; Colonic Aganglionosis)
Hirschsprung's disease is a rare (affects about one in 5,000 US newborns) congenital disorder that results in an obstruction of the bowel. This prevents normal bowel movements. It usually occurs as an isolated finding but can also be part of a syndrome.
Hirschsprung's disease is caused by the absence of certain nerve cells, called ganglia, in the wall of the bowel. Normally, these nerve cells help relax the bowel wall to allow fecal matter to move through the colon. However, in children with Hirschsprung's disease, the colon stays contracted, and bowel contents build up before the obstruction. The condition usually affects the last 1-2 feet of the colon that ends with the rectum.
The absence of ganglia is due to a genetic defect. In some cases, HD is hereditary, which means mothers and fathers could pass it to their children. This can happen even if the parents don't have HD. If you have one child with HD, you could have more children with the disease. Talk to your doctor about the risk and consider genetic counseling.
A risk factor is something that increases your chances of getting a disease or condition. Risk factors for Hirschsprung's disease include:
- Family members with the disease
- more common in males
- may be associated with other congenital defects
Hirschsprung's disease is usually diagnosed in infancy, but can also be diagnosed later. Symptoms can differ with age.
In newborns :
- Failure to pass meconium within the first 48 hours of life (meconium is a dark sticky substance that is the first bowel movement)
- Vomiting after eating
- Abdominal distention
In young children :
- Severe constipation
- Growth delay
In teenagers :
- Severe constipation for most of their lives
Most cases of Hirschsprung's disease are diagnosed in infancy, although some may not be diagnosed until adolescence or early adulthood.
Tests for diagnosis may include:
- Barium enema – injection of fluid into the rectum that makes the colon show up on an x-ray so the doctor can see abnormal areas in the colon.
- Biopsy – removal of a sample of the bowel tissue to check for ganglia (or the absence of ganglia).
- Anorectal manometry – measurement of the pressures of the internal and external sphincter with a rectal balloon.
The primary treatment for Hirschsprung's disease is surgery to remove the affected portion of the colon. There are three potential phases to the surgery, but all three phases may not be needed. Your doctor will discuss the best methods for your or your child's condition.
The three phases are :
- Colostomy – an opening into the colon is surgically created and brought to the abdominal surface. Stool contents are excreted through this opening and into a bag.
- Pull-thorough operation – the affected area of the colon is removed. Then the healthy colon is brought down to the rectum and joined to the rectal wall.
- Closure of the colostomy – the colostomy opening is closed, and bowel function gradually returns to normal.
Symptoms are eliminated in 90% of children after surgical treatment. A better outcome is associated with early treatment, and shorter bowel segment involvement.
Complications may include:
- Perforation of the intestine
- Short gut syndrome
There are no guidelines for the prevention of Hirschsprung's disease.