Prospective evaluation of a clinical decision guideline to diagnose spinal epidural abscess in patients who present to the emergency department with spine pain

Abstract

Object: A spinal epidural abscess (SEA) is rare but potentially devastating if not diagnosed early. Unfortunately, diagnostic delays and associated neurological deficits are common. The objectives of this analysis were to explore the use of a novel clinical decision guideline to screen patients who present to the emergency department (ED) with spine pain for SEA and to determine the diagnostic test characteristics of the erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) level in patients at risk for SEA.

Methods: This was a prospective, cohort analysis comparing the incidence of diagnostic delays and presence of motor deficits at the time of diagnosis before and after implementation of a novel decision guideline using risk factor assessment followed by ESR and CRP testing prior to definitive imaging. A delay was defined as either multiple ED visits or admission to a nonsurgical service without a diagnosis of SEA. A 9-month substudy was performed in all patients who presented to the ED with spine pain so that the diagnostic test characteristics of the ESR and CRP level could be defined.

Results: A total of 55 patients with an SEA in the 9-year control period and 31 patients with an SEA in the 5-year study period were identified. Diagnostic delays were observed in 46 (83.6%) of 55 patients before guideline implementation versus 3 (9.7%) of 31 after guideline implementation (p < 0.001). Motor deficits were present at the time of diagnosis in 45 (81.8%) of 55 patients before guideline implementation versus 6 (19.4%) of 31 after guideline implementation (p < 0.001). The sensitivity and specificity of ESR in patients with an SEA risk factor were 100% and 67%, respectively. The receiver operating characteristic curve analysis revealed better test characteristics for ESR (area under curve 0.96) than for CRP (area under curve 0.81).

Conclusions: A treatment guideline incorporating risk factor assessment followed by ESR and CRP testing was highly sensitive and moderately specific in identifying ED patients with SEA. A decrease in diagnostic delays and a lower incidence of motor deficits at the time of diagnosis was observed.