Hashimoto's encephalopathy: a brief review.

Hashimoto's encephalopathy (HE) is a syndrome of altered mental status, hallucinations, delusional thinking, and often, epileptic seizures. It is diagnosed by the clinical syndrome, the presence of elevated titers of antithyroid antibodies, the lack of another diagnosis based on clinical evaluation, and the response to corticosteroid and other immunosuppressant treatment. This review discusses the symptoms, pathophysiology, and treatment of HE. The disorder is important to recognize because aggressive treatment may bring about a favorable clinical outcome. The disorder has a relatively benign prognosis, compared with many of the entities for which it can be mistaken.