Infectious colitis

Abstract

Infections are a major cause of diarrhea and colitis. Usually, the disease is short-lived and biopsies are not necessary. When the diarrhea is prolonged, biopsies can be taken for solving the differential diagnosis with IBD and microscopic colitis. Most cases of infectious colitis do not present a specific histological pattern. Acute self-limited colitis (ASLC) is the most common pattern in enteric infections. Pathology is not the appropriate tool to identify this problem. The differential diagnosis relies mainly on the absence of features suggestive for IBD such as architectural distortion and basal plasmacytosis. In rare cases, specific infections can be diagnosed such as CMV colitis, spirochetosis, and cryptococcosis. This is also possible for chronic infections such as intestinal tuberculosis. In many developing countries, it is important to recognize this diagnosis and to distinguish tuberculosis from Crohn's disease. Patients with IBD may also present with bacterial or other superinfections. The goals of pathologists are twofold: first, acute self-limited colitis should be distinguished from chronic IBD, ischemia, or other chronic atypical colitides, and second, pathologists have to identify the specific organisms when present.