Toxic Megacolon Clinical Presentation

Updated: Mar 16, 2021
  • Author: Fadi Alali, MD; Chief Editor: Burt Cagir, MD, FACS  more...
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Patients with inflammatory bowel disease (IBD) are at a higher risk of developing toxic megacolon during the early stages of their disease; in some cases, it can be the first manifestation of the disease. [43, 44] Patients with Crohn colitis are more vulnerable than those with ulcerative colitis for developing toxic megacolon. [14]

Findings of ileus may indicate the severity of colitis in patients with C difficile infection. [45]

Patients with toxic megacolon 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. In a paper that studied the clinical presentation of pseudomembranous enterocolitis complicated with toxic megacolon, the presenting symptoms and signs included diarrhea (100%), malaise (91%), abdominal pain (82%), abdominal distention (82%), and abdominal tenderness (72%). [46] However, another study revealed that absence of diarrhea does not rule out the severity of the C difficile infections and the risk of developing toxic megacolon. [47]

A careful history may reveal recent travel, antibiotic use, chemotherapy, occupational exposure, or immunosuppression. Patients are usually very ill, and they can present with signs of fever, tachycardia, hypotension, and/or abdominal distention and tenderness.


Physical Examination

The vital signs in a patient with toxic megacolon generally reveal tachycardia and fever. If the condition is severe, the patient may be hypotensive or tachypneic; patients may be obtunded.

In inflammatory colitides (ie, ulcerative colitis, Crohn colitis), physical findings may be minimal, because high-dose steroids are routinely administered; however, the abdomen may be distended, and the bowel sounds are usually hypoactive. Signs of perforation may also be masked by high-dose steroids.

Peritoneal signs may indicate perforation. They include the following:

  • Rebound

  • Rigidity

  • Peritoneal irritation