Toxic Megacolon Clinical Presentation

Updated: Mar 01, 2018
  • Author: Brian Lin; Chief Editor: Burt Cagir, MD, FACS  more...
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Patients with toxic megacolon (toxic colitis), or TM (TC), typically have signs and symptoms of acute colitis that may be refractory to treatment. Common complaints include diarrhea, abdominal pain, rectal bleeding, tenesmus, vomiting, and fever. The patient may already have a diagnosis of inflammatory bowel disease or another cause of colitis, although in some patients, TM (TC) may be the initial presentation of inflammatory bowel disease.

A careful history may reveal recent travel, antibiotic use, chemotherapy, or immunosuppression. Patients are usually very ill, with the toxic definition including some or all of the following symptoms:

  • High fever

  • Abdominal pain and tenderness

  • Tachycardia

  • Dehydration

The diagnostic criteria developed by Jalan et al may be helpful to guide the history of patient suspected of having toxic megacolon (toxic colitis). They are as follows [3] :

  • Radiographic evidence of colonic dilatation - The classic finding is more than 6cm in the transverse colon

  • Three of the following - Fever (>101.5°F), tachycardia (>120 beats/min), leukocytosis (>10.5 x 103/μL), or anemia

  • One of the following - Dehydration, altered mental status, electrolyte abnormality, or hypotension


Physical Examination

The vital signs in a patient with toxic megacolon (toxic colitis), or TM (TC) generally reveal tachycardia and fever. If the condition is severe, the patient may be hypotensive or tachypneic.

In inflammatory colitides (ie, ulcerative colitis, Crohn colitis), physical findings may be minimal, because high-dose steroids are routinely used; however, the abdomen maybe distended, and bowel sounds are usually decreased. Signs of perforation may also be masked by high-dose steroids, as in inflammatory bowel disease. With toxemia, patients may be obtunded.

Peritoneal signs may indicate perforation. They include the following:

  • Rebound

  • Rigidity

  • Peritoneal irritation

The form of megacolon usually associated with ulcerative colitis is defined by a transverse colon that is 6cm or more in diameter, with loss of haustration.