Pyogenic Sacroiliitis Dx Delayed in Pregnancy.

ARLINGTON, VA. -- The diagnosis of pyogenic sacroiliitis is "always" delayed when the condition arises in pregnancy or peripartum because the hallmark symptoms--hip or buttock pain and tenderness over the sacroiliac joint--are initially attributed to the low back pain typical of pregnancy or delivery.

In addition, the diagnosis is delayed because pyogenic sacroiliitis occurs only rarely in the pregnant or peripartum woman, often fails to induce fever during the initial stages of the infection, and frequently evades detection by x-ray, CT, MRI, or bone scans. "A high index of suspicion is needed to make this diagnosis in a timely way," Dr. M.O. Almoujahed said at the Clinical Research 2001 meeting.

He reported the case of a 26-year-old woman who presented at 24 weeks' gestation with a 2-week history of severe pain in her right buttock that radiated down her leg. The patient had no fever and no history of trauma. She had become unable to walk.

An MRI scan was performed to minimize fetal exposure to ionizing radiation, but the results were "unrevealing," said Dr. Almoujahed of St. John Hospital and Medical Center, Detroit.

The patient's pain and inability to walk persisted despite steroid injections and oral prednisone therapy. Ten days later, a second MRI revealed widening of the sacroiliac joint and anterior fluid collection in the iliacus muscle, suggesting the presence of an abscess. Aspiration yielded purulent material with clusters of gram-positive cocci. Staphyloccocus aureus was confirmed in culture.

The steroids were discontinued and the patient was given intravenous cefazolin for 8 weeks at home, followed by oral antibiotics. She delivered a normal infant at term. At 1-year follow-up, she was ...