Infectious Colitis

Excerpt

Colonic infection by bacteria, viruses, or parasites results in an inflammatory-type of diarrhea and accounts for the majority of cases presenting with acute diarrhea. These patients present with purulent, bloody, and mucoid loose bowel motions, fever, tenesmus, and abdominal pain. Common bacteria causing bacterial colitis include Campylobacter jejuni, Salmonella, Shigella, Escherichia coli, Yersinia enterocolitica, Clostridium difficile, and Mycobacterium tuberculosis. Common causes of viral colitis include Norovirus, Rotavirus, Adenovirus, and Cytomegalovirus. Parasitic infestation, such as Entamoeba histolytica, a protozoan parasite, is capable of invading the colonic mucosa and causing colitis. Sexually transmitted infection affecting the rectum merit consideration during assessment. These diseases can occur in patients with HIV infection and men who have sex with men and may include Neisseria gonorrhoeae, Chlamydia trachomatis, Herpes simplex, and Treponema pallidum.

The patients present with rectal symptoms that mimic inflammatory bowel disease, including rectal pain, tenesmus, bloody mucoid discharge, and urgency. Detailed medical history and identification of specific associated risks are essential in establishing the diagnosis. Stool microscopy and culture and endoscopy are crucial to the diagnosis. However, stool culture helps in the diagnosis of less than 50% of patients presenting with bacterial colitis, and endoscopic examinations usually reveal non-specific pathological changes. Therefore, an approach is needed to evaluate and diagnose the cause of colitis and exclude non-infectious causes. This activity discusses current strategies to diagnose and manage infectious colitis and how to make a high index of suspicion based on clinical presentation and use investigation methods to reach a final diagnosis. This activity discusses the etiology, epidemiology, pathophysiology, clinical presentation, evaluation, differential diagnosis, complications, and management of patients with infectious colitis.