Steroid-Responsive Encephalopathy Associated with Autoimmune Thyroiditis Presenting as Super-Refractory Status Epilepticus in an Adolescent

Dear Editor, Steroid-responsive encephalopathy associated with autoimmune thyroiditis (SREAT) is an uncommon but treatable cause of encephalopathy presenting with neuropsychiatric features and associated with anti-thyroid antibodies and steroid responsiveness. It often poses a diagnostic challenge due to nonspecific investigations and heterogeneous presentation.1,2 Here, we report an adolescent presenting with super-refractory status epilepticus (SRSE) subsequently diagnosed as SREAT, highlighting the importance of early recognition and immunotherapy. A 13-year-old adolescent female on antiepileptic therapy presented with generalized convulsive status epilepticus refractory to intravenous lorazepam, levetiracetam, and sodium valproate. She was intubated and managed in the pediatric intensive care unit with midazolam infusion under continuous electroencephalographic (EEG) monitoring. There was no history of fever, headache, vomiting, or meningeal signs. She had two prior episodes of seizures over the preceding 3 months; neuroimaging, cerebrospinal fluid examination, and EEG were normal at the time of admission. She was discharged on oral levetiracetam after the second episode of seizures. On evaluation, laboratory parameters, including liver and renal function tests and electrolytes, were normal. Cerebrospinal fluid examination was again unremarkable. Magnetic resonance imaging showed bilateral hippocampal hyperintensities on T2-weighted fluid-attenuated inversion recovery sequences. EEG demonstrated generalized slowing with periodic lateralized epileptiform discharges. In the absence of infectious or metabolic abnormalities and with persistent seizures despite anesthetic therapy, an autoimmune etiology was strongly considered. The presence of bilateral hippocampal involvement further supported a limbic process, prompting evaluation for autoimmune encephalitis, including thyroid autoantibodies. Anti–N-methyl-d-aspartate (NMDA) receptor antibodies were negative. Thyroid evaluation revealed low free thyroxine (0.58 ng/dL) and elevated thyroid-stimulating hormone (32.39 µIU/mL), and markedly elevated anti-thyroid peroxidase antibodies (441 IU/mL), suggesting SREAT. She fulfilled the diagnostic criteria for autoimmune encephalitis described by Graus et al.2 Intravenous methylprednisolone (30 mg/kg/day) was initiated on day 3, along with thyroxine supplementation. A rapid clinical and EEG improvement was noted, with successful weaning of anesthetic infusion within 24 h. She was successfully extubated on day 8 and remained seizure-free. At follow-up, recurrence of neuropsychiatric symptoms with rising antibody titers required initiation of azathioprine as a steroid-sparing agent, with subsequent clinical improvement. This case study highlights that SREAT should be actively considered in SRSE with limbic imaging abnormalities, even in the absence of overt thyroid dysfunction. Early recognition and steroid therapy can result in rapid clinical recovery and prevent prolonged intensive care-related morbidity.3,4 Acknowledgements The authors wish to thank Dr. Kavita Shrivastava, Professor and Pediatric Neurologist, and Dr. Rahul Jahagirdar, Professor and Pediatric Endocrinologist, Department of Pediatrics, Bharati Vidyapeeth Deemed to be University Medical College and Hospital. Declaration of patient consent Written informed consent for publication was obtained from the patient’s legal guardian. Ethical policy and Institutional Review Board statement Not applicable for single-patient case reports as per institutional policy. Financial support and sponsorship Nil. Data availability statement No datasets were generated or analyzed during the current study. Conflicts of interest There are no conflicts of interest. Author contributions Concept and design: BUS, NNK. Patient care: BUS, AAW, SR, NNK. Data collection and literature review: NNK, SR. Manuscript drafting: BUS, NNK, SR. Manuscript review and editing: BUS, NNK, SR, AAW. Final approval of the manuscript: All authors.