[Cerebellar syndrome associated with Hashimoto's encephalopathy].

A 38-year-old man presented with an acute confusional state associated with cerebellar signs in left upper limb. Hashimoto's thyroiditis was discovered. Brain magnetic resonance imaging with T2-weighted sequences revealed a high-intensity signal in the left cerebellar hemisphere. The patient received corticosteroids and thyroid hormonal therapy, which was followed by a rapid clinical improvement. The association of an acute confusional state and of cerebellar signs should suggest a Hashimoto's encephalopathy.