[Anti-thyroid antibodies in two patients with subacute dementia, ataxia, and myoclonus].

Hashimoto encephalitis (HE) is a steroid-responsive autoimmune encephalitis with anti-thyroid antibodies; Creutzfeldt-Jakob disease (CJD) is a prion disease. Both disorders can have a similar clinical presentation. Two women, 67 and 63 year-old, with subacute dementia, ataxia, myoclonus and positive antithyroid antibodies were given oral steroids. Whereas one progressively declined and had histopathologically proven CJD, the other made a complete recovery and was diagnosed with HE. Anti-thyroid antibodies can occur in CJD, but when present in a patient with subacute dementia, ataxia and myoclonus, a steroid trial always seems indicated.