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Spinal epidural abscess is a rare but potentially devastating condition. When recognised and treated early the outcome is excellent. 1 Late diagnosis or inadequate treatment may leave the patient with long term severe or disabling incapacity. The need for early diagnosis and the benefits of appropriate early antimicrobial chemotherapy with surgery are discussed.
Epidemiology
Spinal epidural abscess is an uncommon condition with an estimated incidence of 0.2-2.0/10 000 hospital admissions, 2 3 and a peak incidence in the sixth and seventh decades of life. 3 4 At this hospital over a five year period we have seen eight patients admitted from the community with spinal epidural abcess, giving an estimated incidence of 0.25/10 000 admissions. Their median age was 61.5 (range 48-75) The disease is rare in children, with fewer than 90 cases reported. 5 Conditions commonly associated with spinal epidural abcess include diabetes mellitus, intravenous drug misuse, chronic renal failure, alcoholism, and cancer. 2-4
Pathophysiology
Most spinal epidural abcesses are thought to result from the haematogenous spread of bacteria usually from a cutaneous or mucosal source and this occurred in five of our eight patients. In the series by Baker et al, 2 haematogenous spread of infection was identified in 26% of cases, the sources of bacteraemia including furuncles, pharyngitis, and dental abscesses. Haematogenous spinal epidural abcess are primarily located in the posterior aspect of the spinal canal. 6 The direct spread of infection into the epidural space from a source adjacent to the spine-for example, spondylitis or discitis-is also well described. 7 8 In such cases the abscesses are often located in the anterior aspect of the spinal canal and are thought to originate from the adjacent vertebral body. Direct spread from a paraspinal abscess may also occur and was the infective origin in one of our patients. In a recent review of 43 cases of spinal epidural abcess, 44% had coexistent vertebral osteomyelitis. 9 Vertebral osteomyelitis was present in one of our eight patients (12.5%).
Postoperative abscesses account for 16% of all spinal epidural abcesses 2 and epidural catheter insertion is another recognised predisposing factor. 10 11 None of our patients had postoperative abscesses.
Blunt trauma is reported to precede the symptoms of spinal epidural abcess in 15%-35% of cases 7 and...