AUTOIMMUNE ENCEPHALOPATHY ASSOCIATED WITH HASHIMOTOS-THYROIDITIS AS ACAUSE OF PROGRESSIVE DEMENTIA

History and clinical findings: A 58-year-old woman, known for 10 years to have Hashimoto's thyroiditis, was admitted from another hospital w here, after an initial period of unconsciousness, she had developed pr ogressive severe dementia, abnormal arousal and generalized myoclonia. Jakob-Creutzfeldt disease (JCD) was suspected. Investigations: The el ectroencephalogram (EEG) showed marked slowing of the basic activity a nd episodes of triphasic waves. The titres of thyroid antibodies (TPO 764 kU/l, TgAk 398 kU/l) and of the antinuclear antibodies (ANA 1:1280 ) were raised, as was the erythrocyte sedimentation rate (80/120 mm an d the cerebrospinal fluid albumin concentration (1 g/l). Treatment and course: The history and findings suggested autoimmune encephalities ( AIE) and treatment with prednisolone, 2 mg/kg body weight daily, was i nitiated, achieving lasting improvement of arousal within two days. 6 weeks later the EEG merely showed mild alteration of basic activity. T he thyroid antibody titres were now within normal limits and the signs of inflammation were regressing. Conclusion: In case of rapidly progr essive dementia autoimmune antibodies should be looked for in the diff erential diagnosis, because autoimmune disease may be the treatable ca use.