[Hashimoto's encephalopathy: toxic or autoimmune mechanism?]

A 36-year-old woman presented with partial complex status epilepticus. Magnetic resonance imaging with T2-weighted sequences showed a high-intensity signal in the left posterior frontal area. Hashimoto's thyroiditis was then discovered. The disappearance of the high-intensity signal after corticosteroid therapy was suggestive of an autoimmune mechanism. However, improvement could be obtained only with a hormonal treatment, which supports the hypothesis of a pathogenetic role of the Tyrosine-Releasing Hormone (TRH).