“…5 The clinical presentation is highly variable; common clinical features include altered consciousness, tremor, seizures, sleep abnormalities, delusions, hallucinations, stroke-like episodes, and impairment of cognitive function, focal neurological deficits, presenile dementia, psychosis, and ataxia. 6 The specific mechanism of HE is not fully understood, it is believed that brain vasculitis and autoimmune antithyroglobulin or anti-TPO antibodies directed against common thyroid represents the most likely etiologic pathway. 7 Recently International autoimmune encephalitis Society developed clear criteria for, the diagnosis of HE, which are as follows: encephalopathy with seizures, stroke-like episodes, hallucinations, or myoclonus; subclinical or mild overt thyroid disease without severe thyroid dysfunction; normal neuroimaging data or with non-specific abnormalities; presence of serum thyroid peroxidase antibodies, thyroglobulin antibodies; absence of neuronal antibodies in serum and cerebrospinal fluid (CSF); reasonable exclusion of alternative causes.…”