Clinical features of paradiverticulitis.

Colonic diverticula have been generally accepted as a source of massive hemorrhaging. Little is known, however, about fecal occult blood loss from colonic diverticula and diverticulosis. We retrospectively investigated the possibility of minor bleeding in 737 diverticula cases diagnosed from April 1989 to May 1994. Thirty-seven cases (5%) of diverticula are explained as the sources of positive occult blood testing ascertained clearly by colonoscopy. These divide into three types: (1) from intradiverticular bleeding (intradiverticulitis), (2) from peridiverticular bleeding (peridiverticulitis), and (3) from interdiverticular colonic mucosal erosion (interdiverticulitis). These findings account for the occult blood loss that we call paradiverticulitis. The two-year prospective study found 67 cases (11.3%) of paradiverticulitis in 595 diverticula cases. We concluded that paradiverticulitis is one of the causes of positive occult blood tests.