Etiologic diagnosis of viral meningitis. Study of 142 cases

Viral meningitis is a common disease, most often benign and striking predominantly children. In 1997, there was an outbreak of viral meningitis in the North of Portugal and this pathology accounted for 496 admissions to the Infectious Diseases Department of S. João Hospital. The authors' aim was to determine the etiology of the cases of viral meningitis admitted to the S. João Hospital by, in a first phase, searching enterovirus and serology for mumps in a sample of 142 patients with symptoms, signs and cerebrospinal fluid (CSF) cytochemical abnormalities typical of viral meningitis, in the absence of any bacterial or fungal growth (in blood and/or CSF) and with negative soluble bacterial antigens in CSF. The enterovirus was detected by polymerase chain reaction (PCR) and, in a small number of cases, by shell vial culture. The diagnosis of mumps was made by the detection of specific IgM antibodies in serum, using an enzyme-linked immunosorbent assay. The diagnosis was reached in 70 patients (49.3%): 47 (33.1%) had mumps meningitis and 23 (16.2%) enterovirus infection (PCR positive in all; culture positive in only 2 cases). In 72 patients (50.7%), the agent was not identified. Although only two agents were searched for, the diagnosis was made in a high proportion of cases. The culture method used for the isolation of enterovirus was found to have a low sensitivity.