Acute pyogenic sacroiliitis without predisposing conditions.

STUDY DESIGN

Clinical and imaging findings of patients diagnosed with pyogenic sacroiliitis were retrospectively analyzed.

OBJECTIVES

To characterize the clinical and magnetic resonance features of patients with acute pyogenic sacroiliitis without the usually known predisposing conditions and to investigate the diagnostic value of magnetic resonance imaging in detecting the early stages of pyogenic sacroiliitis.

SUMMARY OF BACKGROUND DATA

Pyogenic sacroiliitis is relatively uncommon, and accurate diagnosis is frequently delayed due to lack of awareness by clinicians and nonspecific clinical presentation. There have been few reports that have evaluated the clinical features of acute pyogenic sacroiliitis and investigated the diagnostic capabilities of magnetic resonance imaging in detecting pyogenic sacroiliitis in the early stages.

METHODS

The clinical data of 9 patients (6 male, 3 female; average age 27.3 years) diagnosed with acute pyogenic infection of the sacroiliac joint were retrospectively analyzed. Magnetic resonance images as well as computed tomography of the sacroiliac joints were available in all cases. Seven of the patients underwent 99mtechnetium bone scans.

RESULTS

All patients showed positive findings on magnetic resonance images, whereas 99mtechnetium bone scans were positive in six of seven patients. Eight patients responded well to treatment with intravenous antibiotic therapy, whereas one patient required debridement of the sacroiliac joint following conservative treatment.

CONCLUSIONS

Both magnetic resonance imaging and technetium bone scanning are sensitive for localizing occult sites of bone inflammation. Magnetic resonance imaging may provide more useful information than bone scanning by screening for abnormalities in the sacroiliac joint region. With prompt appropriate antibiotic therapy, clinical improvement of patients can be expected.