What is Hirschsprung’s disease?

Hirschsprung’s disease is a disease that affects your colon (large intestine) causing difficulty to pass stool.  This condition occurs due to missing nerve cells in the muscles of the colon and is present at birth (congenital).  This condition should be considered in babies who fails to pass meconium- the first stool of a baby which has a characteristic green colour- within 24-48 hours.

In the United States, Hirschsprung’s disease affects around 1 case per 5400-7200 newborns annually.  This condition may affect babies of all races but Asian-Americans are 3 times more at risk.  In addition, it is 4 times more common in males than in females.  Around 90% of cases are detected in the newborn period.

The definitive treatment of Hirschsprung’s disease involves surgery to remove the diseased part and reconnect the healthy colon to the rectum.  Nowadays, due to earlier diagnosis and major advances in surgical techniques the mortality rate has decreased significantly.

What are the causes and risk factors for Hirschsprung’s disease?

Hirschsprung’s disease occurs due to missing nerves in your baby’s colon which result in difficulty passing stool.  These nerves are important as they control muscle contractions in the colon that makes it possible to move stool within the colon.  When these nerves are absent, the stool cannot be expelled and may lead to serious infection within the intestines and intestinal obstruction.  Unfortunately, the exact cause of Hirschsprung’s disease is still unknown.  However, there are several factors which may increase the risk of developing this condition and these include:

• Family history: Having a parent or sibling affected by the disease may increase the risk of developing this condition.
• Sex: Males are 4 times more at risk of developing this condition than females.
• Race: Asian-Americans are 3 times more at risk of developing this condition.
• Suffering from other inherited conditions: Down syndrome and congenital heart disease have been associated with Hirschsprung’s disease.

What are the signs and symptoms of Hirschsprung’s disease?

The signs and symptoms of Hirschsprung’s disease include:

• Failure to pass meconium: The signs and symptoms of Hirschsprung’s disease usually become apparent shortly after birth.  If your baby does not pass meconium within 24-48 hours, this condition should be suspected. 
• Chronic constipation: Older with this condition usually have chronic constipation since birth and may show signs of poor weight gain.
• Bilious vomiting: This is vomiting of a greenish or brown substance which indicates bowel obstruction.
• Abdominal distention: This occurs due to retention of faeces in the colon.
• Poor feeding
• Failure to thrive
• Diarrhoea: Diarrhoea occurs when there is an infectious process within the colon due to stool retention.  This may progress to perforation of the colon and causing life-threatening sepsis (when the infection spreads to your blood).

• Excessive fatigue

There are some other diseases which may resemble Hirschsprung’s disease and these include:

• Chronic megacolon
• Constipation
• Hypothyroidism
• Intestinal motility disorder
• Irritable bowel syndrome
• Toxic megacolon

Making a diagnosis

To make a diagnosis your doctor will take a detailed history from you to know more about the symptoms of your baby or child.  After the history taking, your doctor will perform a thorough physical examination to look for signs of Hirschsprung’s disease.  Your doctor will order some tests in order to confirm the diagnosis and prepare your child for surgery.  These include:

• Chemistry panel: This test is done to assess your renal function.  In addition, children suffering from diarrhoea may have findings indicating dehydration.  Furthermore, this test allows your doctor to direct the fluid and electrolyte management properly.
• Complete blood count (CBC): A CBC is done to make sure the preoperative platelet count and haematocrit is suitable for surgery.
• Coagulation studies: This test is done to make sure that any clotting problems are corrected before surgery.
• Plain abdominal radiographs: This test can demonstrate distended bowel loops with the presence of air in the rectum.
• Barium enema: This test is done to assess the diameter of the colon.  Characteristic findings include narrowing of the final part of the colon with dilatation of the upstream part of the colon.

• Anorectal manometry: This test is done to determine whether the muscles of the colon is functioning correctly or not.
• Echocardiography: An echocardiography is done to rule out any heart conditions that may be associated with Hirschsprung’s disease.
• Full-thickness rectal biopsy: This procedure involves your doctor taking a sample of your colon to be examined under the microscope.  This is to demonstrate the absence of nerves in the colon and can be used to establish a definitive diagnosis.

What are the treatments of Hirschsprung’s disease?

The treatment of Hirschsprung’s disease involves medical and surgical care.  Medical care is provided to maintain a normal fluid and electrolyte balance by giving intravenous fluids.  In addition, medications can help to minimize bowel distention, prevent perforation of the colon and treat complications.  Antibiotics may be given if there are signs of infections.  Furthermore, a colonic lavage may be done which involves your doctor inserting a tube into the anus to irrigate the rectum with large volumes of water.

Surgical care is the definitive way to treat Hirschsprung’s disease.  There are 2 types of surgery which may be done.  The first one is known as the pull-through surgery which involves the diseased part of the colon being removed and the healthy part being reattached to the anus by pulling the colon from the inside.  The second type of surgery is called the ostomy surgery.  This surgery is done in 2 steps.  The first step is to remove the diseased part and reattaching the healthy part to an opening (stoma) your surgeon creates in the child’s abdomen so that stool can be collected in a bag (colostomy bag or stoma bag).  Once the colon has healed, your surgeon can then close to stoma and reattach the healthy part of the colon to the anus.

What are the complications of Hirschsprung’s disease?

If Hirschsprung’s disease is left untreated, it may lead to intestinal obstruction, bilious vomiting and perforation of the colon which may lead to life-threatening sepsis.  Complications may arise due to the complex surgery done and these include:

• Enterocolitis: This is severe infection of the intestines and signs and symptoms include diarrhoea, bleeding from the rectum, fever, distended abdomen and vomiting.
• Diarrhoea
• Constipation
• Anastomotic leakage: This is when the connection made between the colon and the anus by the surgeon becomes defective.  Faecal matter then leaks from the colon into the inside of the abdomen which may result in peritonitis- inflammation of the insides of the abdomen.
• Faecal incontinence: This is when you cannot control your bowel movements which results in stool leaking unexpectedly from the rectum.

Prognosis

More than 90% of people suffering from Hirschsprung’s disease obtain satisfactory outcomes.  However, many people experience several years of disturbances of bowel function before normal continence is achieved.  Unfortunately, in 1% of cases, a permanent colostomy may be required due to debilitating incontinence.

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Wagner, J., 2020. Hirschsprung Disease: Background, Pathophysiology, Epidemiology.

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