Life Science Encyclopedia

Toxic megacolon (megacolon toxicum) is a life-threatening complication of other intestinal conditions. It is characterized by a very dilated colon (megacolon), accompanied by abdominal distension (bloating), and sometimes fever, abdominal pain, or shock.

Toxic megacolon is most usually a complication of inflammatory bowel disease, such as ulcerative colitis and, more rarely, Crohn’s disease, and some infections of the colon. Other forms of megacolon exist and can be congenital (present since birth, such as Hirschsprung's disease) or associated with some forms of constipation.

Symptoms

• Abdominal pain
• Abdominal bloating
• Abdominal tenderness
• Fever
• Tachycardia (rapid heart rate)
• Dehydration

There may be signs of septic shock. A physical examination reveals abdominal tenderness and possible loss of bowel sounds. An abdominal radiography shows colonic dilation. There is usually an elevated white blood cell count. Severe sepsis may present with hypothermia or leukopenia.

Treatment

The objective of treatment is to decompress the bowel and to prevent swallowed air from further distending the bowel. If decompression is not achieved or the patient does not improve within 24 hours, a colectomy (surgical removal of all or part of the colon) is indicated. Fluid and electrolyte replacement help to prevent dehydration and shock. Use of corticosteroids may be indicated to suppress the inflammatory reaction in the colon if megacolon has resulted from active inflammatory bowel disease. Antibiotics may be given to prevent sepsis (a severe infection).

Prognosis

If the condition does not improve, there is a significant risk of death. In case of poor response to conservative therapy a colectomy is usually required.

Complications

• Sepsis
• Shock
• Perforation of the colon

Emergency action may be required if severe abdominal pain develops -- particularly if it is accompanied by fever, rapid heart rate, tenderness when the abdomen is pressed, bloody diarrhea, frequent diarrhea, or painful bowel movements.