Pyogenic sacroiliitis.

Two cases of pyogenic sacroiliitis are reported and the literature reviewed. Gluteal pain, tenderness in the sacroiliac area, and pain elicited by maneuvers which stress the joint are characteristic. Delay in diagnosis may result from failure to suspect the sacroiliac joint. Onset is acute in 86% with fever, severe pain, and inability to walk. A bone scan is useful for localization. Blood cultures are positive in one-third. Definitive diagnosis can be established by needle aspiration of the joint, a technically difficult procedure. Therapy is discussed.