Transient neurological symptoms associated with mononuclear pleocytosis of the cerebrospinal fluid.

Brief episodes of neurological dysfunction may sometimes occur in an afebrile patient with no overt vascular disorder, nor any history of previous migraine. In such a case, the cerebrospinal fluid (CSF) may exhibit a predominantly lymphocytic pleocytosis with plasma cells and an increased protein content indicating a lesion of the blood-brain barrier. This syndrome of remitting hemispheric dysfunction is accompanied by migraine-like headache. The available evidence suggests that an aseptic meningitis is the triggering event.