Spontaneous pyogenic vertebral osteomyelitis in nondrug users.

OBJECTIVE: To analyze the clinical, microbiological, and radiologic features of patients without drug addiction suffering from spontaneous pyogenic vertebral osteomyelitis.

METHODS: We collected all microbiologically proved cases of pyogenic vertebral osteomyelitis seen between January 1980 and December 1999 in a teaching hospital. Patients with prior spinal instrumentation or surgery and injection drug users were excluded.

RESULTS: Sixty-four patients, with a mean age of 59 +/- 17 years, were identified. In 29 (45%) patients, 1 or more underlying medical illnesses were found. The mean duration of symptoms before hospital admission was 48 +/- 40 days. Neurologic impairment was present in 18 (28%) patients. Staphylococcus aureus and gram-negative bacilli, mainly Escherichia coli, were the predominant etiologic agents. Blood cultures were positive in 72% (46/64) of cases. The cultures of spinal specimens obtained by x-ray-guided biopsy were positive in 52% (11/21) of cases, and those obtained by open biopsy in 75% (15/20) of cases. Plain radiography showed abnormalities in all but 7 patients. Fifty-one of 53 (96%) technetium Tc 99m diphosphonate bone scans and 40 of 44 (91%) gallium citrate Ga 67 bone scans showed increased uptake of tracers in the involved area. Paraspinal and epidural extension was found on computed tomography and/or magnetic resonance imaging in 74% (39/53) of cases; the presence of an extra-vertebral extension was not associated with the development of neurologic findings in many patients. Two patients died in relation to the infectious process and 3 relapsed; functional sequelae often were found.

CONCLUSIONS: Spontaneous pyogenic vertebral osteomyelitis in nondrug users is a disease that affects mainly older patients suffering underlying medical illnesses. S aureus and E coli are the main causative microorganisms. Positive blood cultures frequently aided the diagnosis. Extra-vertebral extension is frequent but does not indicate a worse prognosis. Although life outcome is good, functional sequelae are common. Diagnostic delay before admission is a concern, and the physician should be alert to the possibility of this condition in patients with back or neck pain.