Spinal Epidural Abscess: A Large Series of 103 Cases

Background: Spinal epidural abscess (SEA) is an uncommon but potentially devastating infection which often eludes early diagnosis. An increasing incidence of SEA cases has been suggested, however few contemporary data are available regarding the potentially changing epidemiology of these infections over time.

Methods: A retrospective study of SEA cases at an academic teaching hospital was conducted using data from 2005-2012. Data collected included sociodemographic factors; medical conditions; causative organism; laboratory data; radiographic imaging; suspected mechanism for development (surgery vs. spinal injection vs. bacteremia); treatment; and outcome.

Results: A total of 103 SEA cases (incidence of 3.9 cases/10,000 admissions) were documented with no significant change in the incidence of cases over the study period. The median age was 58 years, 74% were males, and 90% were white or Hispanic. Location of the SEA was C-spine (15%), T- (17%), L- (50%), and multiple levels (18%). IVDU was noted in 19%, 8% had a preexisting central line; 75% had at least one other underlying medical condition. A causative organism was identified in 77% of cases based on cultures of blood (33%), abscess (30%), or both (37%). The most common identified cause of SEA was Staphylococcus (64%). Other GPCs were identified in 13%, gram-negatives in 14%, and there was one case of brucellosis. Bacteremia was the leading diagnosed route of infection (64%), followed by surgery (26%) and spinal injection (11%). There was no relationship between causative organism and manner of introduction. Over time there was a reduction in the cases linked to spinal injections. All cases received antibiotics (median duration of IV therapy was 8 weeks) and 52% underwent surgery. Lingering neurologic deficits were noted in 8%.

Conclusion: We report one of the largest contemporary series of SEA. Our data found a high incidence of SEA with a >4-fold higher rate than historical data (3.9 vs. 0.5-1 cases/10,000 admissions), but with no recent changes over the study period. Over time, the route of infection was increasingly due to bacteremia versus direct inoculation. Staphylococcus was the predominant causative organism during every year. While the outcome in most cases was favorable, SEA can have devastating consequences and should remain a "not to be missed diagnosis."