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Toxic Megacolon

Definition: Segmental or total colonic distension of >6 cm, in the presence of acute colitis and signs of systemic toxicity.

Toxic megacolon is a potentially life threatening and infrequent complication of CDI; occurring in 0.4 - 3% of cases

Criteria necessary for toxic megacolon diagnosis (3/4 of the following):

  1. Temperature > 101.5oF (38.6oC)

  2. Tachycardia > 120 beats/min

  3. Peripheral WBC count > 10,500/μl with a left shift

  4. Anemia, with a hemoglobin or hematocrit level of < 60% of normal for age

AND at least 1/4 of the following:

  1. Hypotension

  2. Electrolyte imbalances

  3. Mental status changes

  4. Dehydration

Risk factors for toxic megacolon (in addition to CDI) include:

  1. Drugs that slow motility, such as narcotics, antidiarrheals, and anticholinergics

  2. Inflammatory bowel disease

  3. Ischemic colitis

  4. Chemotherapy

  5. Infectious colitis, including Salmonella, Shigella, Yersinia, Campylobacter, Entamoeba, and Cytomegalovirus


These guidelines do not establish a standard of care to be followed in every case. It is recognized that each case is different and those individuals involved in providing health care are expected to use their judgment in determining what is in the best interests of the patient based on the circumstances existing at the time. It is impossible to anticipate all possible situations that may exist and to prepare guidelines for each. Accordingly these guidelines should guide care with the understanding that departures from them may be required at times.