Super refractory status epilepticus as an atypical presentation of Hashimoto's encephalopathy

Hashimoto's encephalopathy (HE), also known as steroid responsive encephalopathy associated with autoimmune thyroiditis (SREAT), is a rare autoimmune disorder characterized by neuropsychiatric manifestations and a favorable response to corticosteroids. Seizures occur in nearly half of patients; however, super refractory status epilepticus (SRSE) is an uncommon initial presentation. We describe a young adult woman with Hashimoto's thyroiditis who developed SRSE after a brief prodrome of headache, confusion, and paranoia. Extensive infectious, metabolic, and autoimmune workup was negative, but anti-thyroid peroxidase and anti-thyroglobulin antibodies were markedly elevated. Brain MRI showed nonspecific subcortical T2/FLAIR hyperintensities. The patient was diagnosed with HE and treated with high dose intravenous methylprednisolone followed by intravenous immunoglobulin, resulting in full neurological recovery and sustained seizure freedom at three-month follow up. This case illustrates the importance of considering HE in patients with unexplained SRSE, as prompt recognition and immunotherapy can be lifesaving.