Hashimoto's Encephalopathy Presenting as Recurrent Brief Psychotic Episodes in a 13-Year-Old Girl: A Case Report

Background: Hashimoto's encephalopathy (HE) is a debilitating manifestation of an autoimmune reaction against the thyroid that rarely can present with prominent psychiatric symptoms. It is often under-diagnosed primarily due to its variety of symptoms as well as a lack of definitive diagnostic criteria. Methods: We report the case of a 13-year-old girl who was diagnosed with HE after presenting with recurrent and severe psychosis with fever and a thyroidopathy. The patient had prominent visual hallucinations and paranoid delusions. Between episodes, the patient did not show evidence of psychiatric symptoms. This patient struggled with several incorrect diagnoses and treatments for two years before the correct diagnosis of HE was made and displayed marked improvement upon corticosteroid administration. Discussion: This case illustrates the importance of increasing awareness of HE as well as including HE in a differential diagnosis when paediatric patients present with psychosis and concurrent thyroidopathy.