Infectious Colitis Mimicking Crohnʼs Disease

Abstract

There have been rare case reports of infectious diarrhea mimicking Crohn's disease. We present two cases of infectious colitis in which the endoscopic and radiographic features, and in one case, biopsies, mimic Crohn's disease. Case #1: A 46 year-old woman presented with 4 days of bloody diarrhea up to 10 times a day and lower abdominal cramps, nausea, and vomiting. She was afebrile and had mild tenderness in her right upper abdomen. She had a normal WBC and a HCT of 27. Multiple stool cultures, including for C. difficile, and ova and parasite tests were negative. CT scan showed diffuse colitis from the sigmoid to the cecum with pericolonic infiltrative changes. Colonoscopy revealed patchy erythema, edema, and ulcers in the cecum and the ascending colon. She was started on mesalamine and IV steroids, as well as antibiotics. Colon biopsies revealed just mucosal erosions. Viral stool cultures were ordered, and were positive for adenovirus.[figure1]FigureCase #2: A 34 year-old man presented with 6 days of nausea, vomiting, and diarrhea up to 15 times a day, with fevers and chills. WBC was normal, fecal leukocytes were >20, and stool cultures were negative. Abdominal CT revealed thickening and stranding around the right colon and terminal ileum. Colonoscopy revealed edema, erythema, and petechiae in a patchy distribution from the rectum to the cecum. A small superficial ulcer was seen in the rectum. The patient was started on mesalamine and antibiotics. Biopsies revealed active, chronic inflammation in the terminal ileum and colon, with glandular architectural distortion. Blood cultures were positive for Salmonella.[figure2]FigureDiscussion: These two cases highlight the rare, but very real, possibilities of infectious colitis mimicking Crohn's disease. These would seem to favor delaying steroids and other aggressive options considered in the “top-down” approach until infectious etiologies are ruled out.