An unusual case of Hashimoto encephalopathy

Introduction. Hashimoto encephalopathy (HE) is a steroid-responsive encephalopathy associated with Hashimoto's thyroiditis (HT). The neurological symptoms are not specific, but two main clinical presentations can be distinguished: a relapsing type, characterized by stroke-like episodes with or without cognitive impairment and confusion, and variably combined with epileptic seizures; and a progressive type, characterized by progressive cognitive impairment to dementia with confusion, psychosis, somnolence or coma; focal or generalized epileptic seizures are present and myoclonus, tremor, as well as ataxia may occur. The diagnosis is supported by an increase in thyroid autoantibodies in the serum, even in the presence of an euthyroid state. So far, no case of purely progressive dementia has been reported. Case report. We report the case of a 63-year-old man referred to our facility in April 2000 for a recent worsening of an Alzheimer's disease diagnosed 5 years before. The patient had a progressive history of topographic disorientation, attention and judgment deficits, and language disturbances, with impact on instrumental activities of daily living. At the time of observation the patient had a moderate cognitive impairment (MMSE of 18/30) and was taking tapazole 2.5 mg because of Graves' disease, with compensated thyroid function. The neuropsychological evaluation demonstrated verbal and visuospatial memory deficits, constructional apraxia, and frontal function deficits. Thyroid microsomal antibodies in the serum were raised (77 I.U./ml, normal