European Journal of Case Reports in Internal Medicine DOI: 10.12890/2015_000178 European Journal of Case Reports in Internal Medicine © EFIM 2015 Doi: 10.12890/2015_000178- European Journal of Case Reports in Internal Medicine- © EFIM 2015 A Rare Cause of

Conflicts of Interests: The authors declare that they have no conflicts of interest in this research This article is licensed under a Commons Attribution Non-Commercial 4.0 License An 81-year-old female patient required numerous admissions for symptoms of confusion, visual hallucinations, myoclonus and seizures, which were treated as stroke, infections and viral encephalitis with some improvement after treatment but with recurrence that caused her to be readmitted to hospital. On the last admission, she was found to have very high antithyroid antibodies and a diagnosis of Hashimoto’s encephalopathy was made, with an overwhelming response to steroids. LEARNING POINTS • Hashimoto’s encephalitis is a rare autoimmune disease that is frequently underdiagnosed. • Exclusion of other pathologies together with a triad of encephalopathy, raised thyroid peroxidase and response to steroids is required for diagnosis