Long-term treatment of Hashimoto's encephalopathy.

Hashimoto's encephalopathy (HE) has been described as an encephalopathy, with acute or subacute onset, accompanied by seizures, tremor, myoclonus, ataxia, psychosis, and stroke-like episodes, with a relapsing/remitting or progressive course. HE patients have positive antithyroid antibodies, are usually in a subclinical hypothyroid state, have elevated cerebral spinal fluid (CSF) protein, and have nonspecific electroencephalogram (EEG) and imaging abnormalities in the absence of CNS infection, tumor, or stroke. The authors present two cases of HE, demonstrating an excellent response to high dose steroids acutely followed by long-term treatment with steroids and other immunomodulatory agents. A review of the literature is also provided.