Spondylodiscitis (disc space infection) associated with negative microbiological tests: comparison of outcome of suspected disc space infections to documented non-tuberculous pyogenic discitis.

Discitis, an infection of the disc space, is an uncommon diagnosis that, if missed, can lead to spinal deformity and neurological deterioration, although as many as 30% of these patients will have negative microbiological cultures. It was unclear, however, whether the prognosis differed between patients who had positive or negative cultures. A retrospective case note review was carried out to assess the differences in presentation and outcome between these two groups. There were 26 and 43 patients in the negative and positive groups, respectively. Those with a positive culture were more likely to present with pyrexia, have a neurological deficit and not be independently mobile at presentation. The mean CRP recorded at the time of presentation was 96 and 157 in the negative and positive groups respectively (p = 0.004). Similarly, the mean ESR in the positive group was 88 compared with 69 in the negative group (p = 0.02). In conclusion, these patients may be at different ends of a clinical spectrum: those patients with a positive culture having a greater local and systemic inflammatory reaction to the disc space infection.