[Viral or bacterial meningitis. Differential diagnostic problems]

A 19 year old previously healthy man presented symptoms of meningitis. Culture from the cerebrospinal fluid revealed herpes simplex virus type 2 to be the responsible agent. The course was benign, the patient was never seriously ill. He recovered fully within a few weeks. The cerebrospinal fluid showed prolonged pleocytosis and low values of glucose. The traditional cerebrospinal fluid parameters employed in the diagnosis of meningitis, and for distinguishing bacterial from viral meningitis, are shown to be inadequate in many cases. Of these tests cerebrospinal fluid differential cell count is of most value, especially if repeated after 12 hours or so in the initial course. Additional tests have been proposed, none of which have proven to be of much help, except perhaps the test for lactate in the cerebrospinal fluid.