Spinal Epidural Abscess: A Series of 101 Cases

Spinal epidural abscesses are uncommon but potentially devastating infections that often elude early diagnosis. An increasing incidence has been suggested; however, few contemporary data are available regarding risk factors and epidemiologic trends over time.

A retrospective study of spinal epidural abscesses from 2004 to 2014 at a large academic hospital was conducted. Cases were identified using International Classification of Diseases, Ninth Revision (ICD-9) code 324.1, and a review of medical and radiographic records was performed to confirm each case. Data collected included sociodemographics, medical history, suspected route of infection, treatments, and outcome.

The incidence was 5.1 cases for each 10,000 admissions, with no significant changes during the study period. The route of infection was identified in 52% of cases, with bacteremia as the most common (26%), followed by recent surgery/procedure (21%) and spinal injection (6%). An identifiable underlying risk factor was present in 84% of cases, most commonly diabetes and intravenous drug use. A causative organism was identified in 84% of cases, most commonly Staphylococcus aureus; methicillin-resistant isolates accounted for 25% of S. aureus cases. All cases received intravenous antibiotic therapy, and 73% underwent a drainage procedure. Fifteen percent had an adverse outcome (8% paralysis and 7% death).

The incidence of spinal epidural abscesses may be increasing, with the present study demonstrating a ≥5-fold higher rate compared with historical data. Although the outcome in most cases was favorable, spinal epidural abscesses continue to cause substantial morbidity and mortality and should remain a "not to be missed diagnosis."