Clinical relevance of hydrocephalus in bacterial meningitis in adults

The predictive factors, clinical relevance, and outcomes of hydrocephalus complicating adult bacterial meningitis were studied.

In this 16-year retrospective study, 136 adult patients were identified with culture-proven bacterial meningitis. A comparison was made between the clinical and cerebrospinal fluid data of patients with and without hydrocephalus on admission.

Twenty-eight patients had hydrocephalus secondary to bacterial meningitis, accounting for 21% (28/136) of the episodes. Of the 28 patients, the initial computed tomographic scans and/or magnetic resonance imaging studies revealed hydrocephalus in 27 patients, and delayed hydrocephalus developed despite commencement of antimicrobial therapy in the remaining patient. The interval from initial symptoms to external ventricular drainage was 3.9 +/- 4.6 days (range, 1-14 days). Among them, 7 patients underwent external ventricular drainage for hydrocephalus during the acute phase of bacterial meningitis. At follow-up of at least 6 months or more, 14 patients survived and 14 died, with an overall mortality rate of 50%.

In this study, disturbed consciousness and a higher mean age at the time of admission are risk factors for developing hydrocephalus during the acute phase of bacterial meningitis. Poor outcomes are also found in this specific group of patients, and these may be attributed to the infection itself, hydrocephalus, or both. Because of fulminated clinical courses and high fatality rates, surgical intervention may be suitable only for those who have progressive hydrocephalus and are neurologically stable. In spite the high fatality rate, adequate treatment of neurologic complications and aggressive antimicrobial therapy are essential in improving therapeutic outcomes.