Hashimoto's encephalopathy: neuropsychological findings.

Hashimoto encephalopathy (HE) is a rare and often reversible neurological syndrome associated with autoimmune thyroiditis and steroid-responsiveness. This syndrome includes behavioral symptoms like delusions and delirium, mood disturbances, epilepsy, progressive cognitive impairment and alteration of vigilance and consciousness with confused state until coma. Two subtypes of clinical presentation are described: ictal onset with seizures and stroke like episode and insidious onset with progressive dementia. The pathogenesis is uncertain; several theories have been proposed: autoimmune, vasculitic and demyelinating. Here, we report the case of a patient with HE who was submitted to exhaustive neuropsychological exams in the premorbid and the acute phase, and following resolution of the acute phase. After the initial confusional state resolved, results of the neuropsychological exams revealed a diffuse pattern of cognitive impairment that eventually evolved toward a selective deficit in executive functions. This pattern of cognitive impairment suggests that, after an initial phase characterized by diffuse brain involvement, our patient was primarily affected by frontal lobe sufferance.