Adult meningitis in a setting of high HIV and TB prevalence: findings from 4961 suspected cases
1 Infectious Diseases Unit, GF Jooste Hospital, Cape Town, South Africa
2 Desmond Tutu HIV Centre, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Cape Town, South Africa
3 Centre for Infection, Department of Cellular and Molecular Medicine, St George's University of London, Cranmer Terrace, London SW17 0RE, UK
4 Division of Infectious Diseases and HIV Medicine, Department of Medicine, University of Cape Town, Cape Town, South Africa
5 Institute of Infectious Diseases and Molecular Medicine, University of Cape Town, Cape Town, South Africa
BMC Infectious Diseases 2010, 10:67 doi:10.1186/1471-2334-10-67Published: 15 March 2010
The presentation and causes of adult meningitis in South Africa have changed substantially as a result of HIV. Knowledge of aetiology and laboratory findings in patients presenting with meningitis are important in guiding management. We performed a retrospective study to determine these findings in a setting of high HIV and TB prevalence in Cape Town.
Patients undergoing lumbar punctures between 1st January 2006 and 31st December 2008 at a public sector referral hospital were studied. Cases were classified by microbiological diagnosis, or in the absence of definitive microbiology as 1) normal CSF (neutrophils ≤ 1 × 106/L, lymphocytes ≤ 5 × 106/L, protein ≤ 0.5 g/dL, glucose ≥1.5 mmol/L), 2) minor abnormalities (neutrophils 2-5, lymphocytes 6-20, protein 0.51-1.0, glucose 1.0-1.49) or 3) markedly abnormal (neutrophils>5, lymphocytes>20, protein>1.0, glucose<1.0).
5578 LPs were performed on 4549 patients, representing 4961 clinical episodes. Of these, 2293 had normal CSF and 931 had minor abnormalities and no aetiology identified. Of the remaining 1737, microbiological diagnoses were obtained in 820 (47%). Cryptococcus accounted for 63% (514) of microbiological diagnoses, TB for 28% (227), bacterial meningitis for 8% (68). Of the remaining 917 who had marked abnormalities, the majority (59%) had a sterile lymphocytic CSF. Of note 16% (81) patients with confirmed Cryptococcus, 5% (12) with TB and 4% (3) with bacterial meningitis had normal CSF cell-counts and biochemistry.
Cryptococcal and tuberculous meningitis are now the commonest causes of adult meningitis in this setting. TB meningitis is probably underdiagnosed by laboratory investigation, as evidence by the large numbers presenting with sterile lymphocytic markedly abnormal CSFs.