The Ever-Changing Landscape of Drug-Induced Injury of the Lower Gastrointestinal Tract

-There is an ever-growing armamentarium of pharmacologic agents that can cause gastrointestinal (GI) mucosal injury, the most common symptoms being diarrhea, constipation, nausea, and vomiting. These are often self-limiting and without serious sequelae, but some symptoms are of greater concern, like drug-induced mucosal ulceration that can manifest as GI hemorrhage, stricture formation, and even perforation. Histologically, there is significant overlap between drug-induced injuries and various disease entities. A single type of medication may cause multiple patterns of injury, which can involve the entire GI tract or just some parts of it.

-To review the most common drug-induced injury patterns affecting the colon, which may be recognized by the surgical pathologist on colonic mucosal biopsies. This review does not address the injuries occurring in the upper GI tract.

-A PubMed review of English-language literature, up to December 2015, on drug-induced injury of GI tract was performed.

-There are numerous drugs that damage the colonic mucosa. The most common drugs are included in this review according to their histologic pattern of injury. It is important for the pathologist to keep in mind that a single drug type can induce many histologic patterns of mucosal injury that can mimic many disease entities. Although there are some histologic clues helpful in the diagnosis of drug-induced colonic injury, correlation with clinical history and especially medication history is essential to improve diagnostic accuracy.