CT appearance of antibiotic-induced colitis.

Eleven abdominal computed tomographic (CT) examinations were performed in 10 patients with antibiotic-induced colitis. The clinical, endoscopic, and CT findings are presented. The most common CT findings were colonic dilatation and bowel wall thickening. However, small bowel dilation was commonly seen. Intramural gas and ascites were less frequent findings. The diagnosis of antibiotic-induced colitis was rarely made before CT examination. Consequently, attentiveness to these CT abnormalities can expedite specific treatment. When these findings are noted on CT they represent the equivalent of toxic megacolon and administration of rectal contrast is contraindicated.