Spinal epidural abscess--experience with 46 patients and evaluation of prognostic factors.

OBJECTIVE Spinal epidural abscess is a rare infectious disorder, often with a delayed diagnosis, and associated with significant morbidity and mortality rates. We conducted a retrospective study to define its clinical characteristics and to evaluate its prognostic factors. METHODS The medical charts of 46 patients (36 men and 10 women) with spinal epidural abscess over a 10-year period (from July 1991 to May 2000) were reviewed and analyzed. RESULTS A high proportion of patients had underlying diseases of diabetes (46%), frequent venous puncture (35%), spinal trauma (24%), and history of spinal surgery (22%). The initial accurate diagnostic rate was 11%. Localized spinal pain (89%), paralysis (80%), fever/chills (67%), and radicular pain (57%) were the common manifestations. The erythrocyte sedimentation rate (ESR) was elevated uniformly (mean, 86.6 mm/h) when measured. Staphylococcus aureus was the most common cause of spinal epidural abscess isolated from blood (39%) and pus (50%). Low platelet counts (< 100 x 10(9)/L) (odds ratio (OR): 8.8, 95% confidence interval (CI): 1.0-77.8), extremely high ESR (> or = 110 mm/h) (OR: 4.8, 95% CI: 0.9-25.4), and cervical spine epidural abscess (OR: 5.2, 95% CI: 0.8-32.0) predicted a poor outcome. CONCLUSIONS Localized back pain in a febrile patient with significant risk for epidural abscess warrants an immediate magnetic resonance imaging examination. The presence of thrombocytopenia, extremely elevated ESR, or evidence of spinal cord compression should prompt aggressive treatment.