Unspecific Colitis due to Shigellosis (4 of 7)

Endoscopic View of Colitis due to Shigellosis Pathologically, shigellosis is characterized by an acute diffuse inflammation of the colon with initial hyperemia of the mucosa, followed by edema, hemorrhage, and infiltration with leukocytes and macrophages. This process often extends into the submucosa, causing marked thickening of the intestinal wall. Epithelial necrosis and desquamation with formation of a membrane are followed by sinuous ulceration, originating on the tops of the intestinal folds and often extending deep into the submucosa and occasionally into the muscularis; perforation is rare. Inflammation is not usually uniformly distributed throughout the colon but is most severe in the distal portion from sigmoid colon to anus. The terminal ileum is occasionally involved. Secondary bacterial infection occurs once ulcerative lesions have developed, and may be important in the subsequent development of a chronic state of the disease. In patients in whom dysentery has been of long duration, adjacent ulcers may be joined by ulcerating channels beneath bridges of hyperplastic mucosa.