Fibrin thrombi, a cause of clindamycin-associated colitis?

Rectal biopsies from five patients with clindamycin-associated colitis were studied with the intention of identifying fibrin thrombi in capillaries. Capillary thrombosis was present in all five cases, three with pseudomembranous colitis and two with non-specific colitis. The significance of capillary thrombosis and its relationship to other ischaemic lesions of the gut are discussed.