[Rhythmic fast activity on EEG in a patient with Mollaret's meningitis]

Mollaret's meningitis is a rare disease of unknown etiology, characterized by repeated aseptic meningitis with transient neurological symptoms and quick recovery. The patient, a 16-year-old boy, had episodes of acute encephalitis followed by complete recovery every year from the age of 13 to 16 years. The symptoms at onset were loss of consciousness, a generalized tonic clonic seizure and pyramidal signs. He was first admitted to our hospital at the age of 15 years. EEG in the early stage showed diffuse low-voltage rhythmic fast actvity. He recovered consciousness after a week. At the age of 16 years, he was admitted again because of high fever (39 degrees C). Soon after admission, he had generalized tonic-clonic seizure and was accompanied by alternating deep coma and delirium. Cerebrospinal fluid examination during early stage revealed mild leukocytic pleocytosis, elevation of protein and a high level of IL-6. although brain CT and MRI showed no abnormal findings. EEG showed intermittent, diffuse, middle-voltage, rhythmic fast activity. After 5 days, the neurological symptoms completely disappeared with EEG normalization. To our knowledge, this is the first report of rhythmic fast activity on EEG in Mollaret's meningitis. The clinical pictures of this case suggest a transient functional disorder of brainstem or cerebrum may occur in this condition.