Pyogenic sacroiliitis.

Seven definite and three probable cases of pyogenic sacroiliitis are presented and compared to 72 cases found in the English literature. Patients may present with a subacute localized or an acute systemic illness. Six of our patients were parenteral drug abusers. Symptoms often were vague, but sacroiliac tenderness was invariably found on examination. Sacroiliac uptake of gallium67 citrate and/or technetium99m pyrophosphate suggested the diagnosis which was confirmed by fluoroscopically controlled joint aspiration when blood cultures were sterile. Gram-negative organisms, group B streptococci and a Staphylococcus were isolated. Antibiotic treatment for four to six weeks was uniformly successful. Surgery should be reserved for abscess or sequestrum formation, neither of which were encountered in this series.