Hashimoto's encephalopathy with selective involvement of the nucleus accumbens: a case report.

Hashimoto's encephalopathy (HE) is an acute or subacute relapsing disorder usually affecting euthyroid patients with evidence of autoimmune thyroiditis. The neurological manifestations are non-specific, with subacute cognitive impairment, movement disorders, generalized seizures, focal neurological symptoms such as stroke-like episodes, or psychiatric disturbances. Autoimmune phenomena are likely to play an etiological role. Magnetic resonance imaging (MRI) findings are usually normal or show non-specific changes. We report the case of an 11-year-old girl with autoimmune thyroiditis who presented acutely with a complex neuropsychiatric disorder in association with MRI evidence of focal involvement of the nucleus accumbens (NA). The NA, a ventral striate nucleus, is part of a complex dopaminergic network. Lesions to the NA result in several psychiatric symptoms, such as attention-deficit hyperactivity disorders. In this patient, we observed alternating phases of stupor and hyperkinetic-anxious behavior, with marked instability. The pathogenetic mechanism and the anatomic and functional correlations are briefly discussed.