Lymphocytic meningitis: incidence, causes and outcomes over five years.

Over a five-year period 114 cases of lymphocytic meningitis were admitted to a general hospital. Case notes were reviewed to determine incidence, causes and outcomes and to identify what clinical features, cerebrospinal fluid (CSF) parameters or other tests were useful in elucidating a cause. Of 114 patients with lymphocytic meningitis 44 had viral meningitis, six viral encephalitis, and seven had other infective meningo-encephalitis. Seven patients had carcinomatous meningitis, nine had an autoimmune/inflammatory process, thirteen had a demyelinating central nervous system (CNS) disorder, and two had an inflammatory neuropathy. In 26 patients no diagnosis was reached. Six of these showed clear steroid responsiveness. Overall lymphocytic meningitis had a good prognosis. Clinical and CSF characteristics were important in diagnosis and prognosis. Recommendations on management of these cases are presented.