Over the 3-year study period 5578 LPs were performed
on 4549 patients, representing 4961 clinical episodes.
Forty-three percent of patients were male, and the median
age was 34 years. Of these 4961 clinical episodes,
2293 had a normal CSF and no microbiological diagnosis.
A further 931 episodes had minor abnormalities and
no aetiology identified, compatible with the pleocytosis
seen in HIV infection. Of the remaining 1737 episodes,
microbiological diagnoses were obtained in 820 (47%).
See figure 1.