Diagnostic lumbar puncture in HIV-infected patients: analysis of 138 cases

This study was designed to describe the cerebrospinal fluid (CSF) findings and neurologic diagnoses observed in human immunodeficiency virus (HIV)-infected adults undergoing diagnostic lumbar puncture (LP) and to correlate the results of LP with indications and CD4 counts.

Retrospective cross-sectional chart review study.

University hospital clinic for patients with HIV infection.

All patients of the University of California, San Francisco (UCSF) AIDS Clinic who underwent LP between mid-1987 and mid-1990 for headache, fever, altered mental status, or a combination of these indications. Sixty-seven percent had an AIDS diagnosis at the time of LP; the median CD4 count was 0.091 x 10(9)/L.

A total of 138 LPs was analyzed. Elevation of CSF protein and leukocytes occurred in 33% and 27% of specimens, respectively. Seventy-two new neurologic diagnoses were established in 67 patients, but only 30 diagnoses were the result of CSF analysis. Of these 30 diagnoses, 18 were of aseptic meningitis attributed to HIV. None of the 12 treatable diagnoses established by LP occurred in patients known to have a CD4 count of 0.200 x 10(9)/L or greater. Patients undergoing LP because of headache had a lower incidence of new diagnoses than those with altered mental status (35% versus 72%), but LP revealed a higher proportion of diagnoses in the group with headache.

CSF abnormalities were common at all stages of disease. LP was diagnostic in 22% of cases, but fewer than half of the diagnoses were of treatable secondary complications. Patients with a CD4 count higher than 0.200 x 10(9) have a very low incidence of opportunistic complications. The relatively low yield of LP in patients with altered mental status suggests that other testing modalities should be used prior to LP.