[Sub-acute encephalopathy that responds to steroids without any evidence of autoimmune thyroid disease: a case of non-vasculitic autoimmune meningoencephalitis].

Aim: To report a case of sub-acute encephalopathy with all the extension study negative and with response to steroid therapy.

Case Report: The study involves a 22-year-old female with no relevant past history who presented symptoms of sub-acute encephalopathy consisting in behavioural disorders, generalised seizures and bradypsychia, which gradually progressed to a state of low-level consciousness. While she was in hospital all kinds of diagnostic tests were conducted, the results of which were either normal or negative; the electroencephalogram was repeatedly abnormal and detection of protein 14-3-3 in cerebrospinal fluid was positive. Empirical corticoid therapy was begun with clinical and electrophysiological improvements and the patient recovered completely without any sequelae.

Conclusions: With no evidence of autoimmune thyroid disease, although non-specific autoimmunity was present, the patient was diagnosed as having non-vasculitic autoimmune meningoencephalitis.