Fig. 1Putative pathophysiology of NSAID-induced enteropathy. NSAIDs decrease PG synthesis, resulting in the reduction of mucus and blood flow of the intestinal mucosa and directly damage the small bowel epithelium. These injuries cause increased intestinal permeability of bile acid, bacteria, proteolytic enzymes, and toxins. Therefore, neutrophils and many inflammatory mediators are activated and various clinical manifestations, such as erosion, ulceration, bleeding, and protein loss develop. Additionally, enterohepatic circulation of NSAIDs and bile augments the damage to the small bowel. TLR4, Toll-like receptor 4. Adapted from Wallace JL. Br J Pharmacol 2012;165:67-74.18
Fig. 2Capsule endoscopic images of various intestinal mucosal lesions by NSAID. (A) Small bowel petechiae, (B) small bowel erosion, (C) small bowel ulcer, (D) small bowel ulcer with adherent blood clots, (E) small bowel active bleeding, and (F) small bowel stricture with adherent clots.