Summary

Hashimoto encephalopathy has a wide clinical spectrum with various neuropsychiatric features. The detection of anti-thyroid antibodies in patient sera is helpful, but alone not sufficient for the diagnosis of Hashimoto encephalopathy because of the high prevalence of antibodies in the normal population. Here, a patient with Hashimoto encephalopathy, who presented with progressive cerebellar ataxia with mild abnormality on electroencephalography (EEG) and who showed marked improvement after steroid administration, is described. This emphasises that Hashimoto encephalopathy can present with isolated cerebellar ataxia and is responsive to immunosupression.