Toxic megacolon in ulcerative colitis. Early diagnosis and management.

The diagnosis of toxic megacolon is based on a thorough history and physical examination, simple laboratory tests, and careful examination of plain abdominal films. As with other uncommon conditions, making the correct diagnosis requires a high index of suspicion. This is especially true when toxic megacolon is the initial manifestation of ulcerative colitis. In this setting, a previous history of chronic diarrhea may be lacking. Patients with toxic megacolon are usually first seen in the emergency room, so the diagnosis must be entertained in all patients presenting with abdominal distention and acute or chronic diarrhea. The diagnosis of toxic megacolon does not require CT scans, ultrasound examinations, radionuclide scans, colonoscopy, or barium enema. In fact, reliance on those nonessential diagnostic procedures may delay diagnosis while the patient continues to deteriorate. Once toxic megacolon is diagnosed, the patient should be admitted immediately to an intensive care unit for careful monitoring by both medical and surgical staff.