Hashimoto's encephalopathy: exacerbations associated with menstrual cycle.

The authors report a patient who had five relapses of encephalopathy with seizures and aseptic meningitis that coincided with the end of the menstrual cycle. High titers of antithyroid antibodies and the patient's response to corticosteroids suggested Hashimoto's encephalopathy. Pharmacologic suppression of the menstrual cycle made it possible to withdraw corticosteroids.