Steroid-Responsive Encephalopathy Associated with Autoimmune Thyroiditis: Case Report – Significance of History, Suspicion, and Imaging

Steroid-responsive encephalopathy associated with autoimmune thyroiditis (SREAT) is a rare but potentially reversible autoimmune neurological disorder characterised by a wide spectrum of neuropsychiatric manifestations, seizures, and encephalopathy. Owing to its protean clinical presentation and frequently nonspecific conventional investigations, SREAT is often misdiagnosed as a primary psychiatric illness or cryptogenic epilepsy. We report a case of a young male presenting with acute psychosis in whom multimodal neuroimaging using contrastenhanced magnetic resonance imaging (MRI) of the brain and 18F-fluorodeoxyglucose-positron emission tomography (FDG-PET)/computed tomography (CT) revealed limbic and functional cerebral involvement, respectively. Early recognition and prompt immunotherapy resulted in significant clinical improvement. This case highlights the complementary role of structural and functional neuroimaging in establishing the diagnosis of SREAT. The patient was initially misdiagnosed as schizophrenia due to predominant hallucinations and cognitive decline in the absence of overt seizures, highlighting the diagnostic challenge posed by autoimmune encephalopathies with psychiatric presentations.