Lymphocytic Meningitides and Meningoencephalitides
In cases in which the lymphocytic meningitides take the usual, relatively benign course, the cause is usually a member of the enterovirus group. A benign lymphocytic meningitis may also be observed accompanying mumps and almost all herpes zoster infections. Pleocytosis of the CSF is often very limited in cases of herpes zoster meningitides (40/mm3), extensive in the majority of Coxsackie infections (up to 3,000/mm3) and does not exceed 1,000/mm3 in most forms of viral meningitis. There seems to be no correlation between the number of cells in the spinal fluid and the severity of illness, although it is most often the meningitis accompanied by a limited pleocytosis that is clinically asymptomatic. On the other hand, a mild pleocytosis is sometimes an early sign of a serious encephalitic illness.