Pseudomembranous Colitis (7 of 11)

The presence of pseudomembranes is virtually diagnostic of pseudomembranous colitis. In general, colonoscopy is superior to sigmoidoscopy because in 10% of patients, pseudomembranous colitis is rectosigmoid-sparing. The findings with colonoscopy vary from diffuse, patchy colitis in mild cases to the characteristic raised, adherent, yellow plaques seen in pseudomembranous colitis. Other endoscopic findings include erythema, edema, friability, and erosions. Histologically the condition is characterized by pseudomembranes which represent exudate of necrotic cells from the denuded mucosa. The diagnosis is typically made with stool assay for the C.difficile toxin or by stool culture.