1. Inflammation of a diverticulum, especially of the small pockets in the wall of the colon which fill with stagnant fecal material and become inflamed; rarely, they may cause obstruction, perforation, or bleeding.
2. Inflammation of a diverticulum, especially inflammation related to colonic diverticula, which may undergo perforation with abscess formation; sometimes this is called left-sided or L-sided appendicitis.