Diagnosis of Spinal Epidural Abscess by Abdominal Plain-Film Radiography

A 57-year-old male with a history of diabetes mellitus, hepatitis C, and intravenous drug abuse presented to the emergency department complaining of abdominal pain of three months duration that had worsened in the week prior to presentation. Review of systems was significant for back pain, nausea, and fever. The patient’s physical examination demonstrated a diffusely tender abdomen in addition to bilateral costo-vertebral angle tenderness, bilateral lower extremity weakness, and decreased rectal tone. An acute abdominal series was ordered to evaluate for bowel perforation (Figure). After review of this radiograph, magnetic resonance imaging (MRI) of the thoracic spine was ordered to confirm the suspected diagnosis of epidural abscess (Figure). The patient was transferred to the operating room for successful thoracic hemi-laminectomy and discharged home on post-op day seven. The incidence of spinal epidural abscess has been estimated to account for 0.2-2.0 per 10,000 admissions, although recent studies report that the incidence is rising owing to increased rates of intravenous drug abuse and spinal surgical instrumentation.1,2 While the utility of plain film radiography is limited in the initial evaluation of suspected epidural abscess, abnormalities suggesting the presence of the disease in the form of end plate erosions or findings suggestive of osteomyelitis should not be ignored as these findings may be present in up to 89% of cases.3-5 In contrast, MRI with gadolinium contrast has a reported sensitivity of 91% with an associated specificity of 100%, rendering it the imaging modality of choice.5-7 Timely diagnosis of this relatively rare condition is paramount as the associated mortality of 5-16% is significant.8,9