What is megacolon?

Megacolon is a medical condition characterized by the dilation of the colon, which can be congenital or triggered by the presence of infection or an intestinal obstruction. Regardless of the cause, all presentations of this condition often induce similar symptoms. Treatment depends on the underlying cause and often involves the administration of intravenous fluids to prevent dehydration and corrective surgery to restore proper function of the colon.

Toxic megacolon is considered a life-threatening complication associated with the existence of an underlying intestinal condition. The presence of inflammation and infection contributes to the toxicity of the condition that causes dilation of the large intestine. Symptomatic individuals may experience a variety of symptoms that may include abdominal discomfort, tenderness, and bloating. Additional signs of toxicity may include elevated heart rate, fever and nausea, and in extreme cases shock.

Congenital megacolon is an intestinal blockage due to impaired muscle movement within the intestine. Due to the lack of nerves within the intestine, the intestinal contents accumulate, causing abdominal distention and intestinal dysfunction. Often diagnosed in infancy, this condition causes newborns to develop constipation, bloating, and vomiting. Additional symptoms may include the absence of a first stool (merconium), jaundice, and watery diarrhea.

A primary intestinal obstruction can occur in the small or large intestine and can present as an acute or chronic condition. Frequently diagnosed in children and the elderly, this form of colonic dilatation is idiopathic in nature, meaning there is no known cause in the absence of inflammation or infection. People with chronic conditions, such as cerebral palsy or other neurological disorders, or those who are bedridden are generally at higher risk of developing this condition. Those who become symptomatic with nontoxic forms of colonic dilation may experience abdominal discomfort, nausea, and vomiting.

The diagnostic tests used to confirm the presence of a dilated colon vary. In the presence of abdominal distention, a physical examination and palpation of the affected area may be performed. Any abnormalities discovered during a preliminary exam will usually prompt additional testing. If a toxic megacolon is suspected, further testing may include administration of an abdominal x-ray and blood tests to assess electrolyte levels and detect the presence of markers indicative of infection.

Babies suspected of having congenital megacolon may receive a barium enema and abdominal X-ray to confirm the presence of bowel dysfunction. A rectal exam can determine the presence of altered rectal muscle tone, which may contribute to the manifestation of symptoms. In some cases, anal manometry may also be performed to assess rectal pressure.

If a bowel obstruction is suspected, a barium test may be performed to confirm the presence and location of the blockage. Prior to testing, an individual is given barium, either orally or as an injection, which is then tracked with the use of X-rays to assess the condition and functionality of the upper gastrointestinal tract and related organs, including the bowels. Esophageal manometry may be performed to assess the condition of the esophagus, and bowel function may be assessed with an intestinal radionuclide scan.

Treatment for toxic megacolon has a multifaceted approach. To reverse the effects of the condition, intravenous fluids may be given to prevent dehydration, and if the colon has been perforated, a partial or complete excision of the colon, known as a colectomy, may be performed. To prevent the spread of infection, which can lead to sepsis, antibiotics may also be given. Due to a significant risk of death, prompt and appropriate treatment for colonic dilation is essential. Complications associated with this condition can include shock, sepsis, and perforation of the colon.

Congenital megacolon often requires removal of the abdominal portion of the colon and rectum. The remaining colonic tissue is used to function in place of the removed portion. Before surgery, the intestine is decompressed to relieve pressure and allow easier manipulation of the organ. The procedure is often done during two separate surgeries, both of which can be completed before the child is one year old. Complications associated with this corrective surgery can include short bowel syndrome, intestinal inflammation, and intestinal perforation.

Nontoxic colonic dilation can also be treated with medication and surgery. A colonoscopy may be used to relieve trapped air, and intravenous fluids may be given to prevent dehydration that can result from excessive nausea and vomiting. Additional treatment for this potentially recurring condition may include the use of nasogastric suction, which involves placement of a nasogastric (NG) tube to decompress the intestine, and dietary changes. People with this form of megacolon usually show improvement within a few days of treatment. Complications can include diarrhea, unintentional weight loss, and vitamin and mineral deficiencies.

Go up