Spectrums of encephalopathy associated with antithyroid antibodies

Abstract

Aim Illustrate encephalopthies associated with antithyroid antibodies through two cases. Case 1 A child with known hypothyroidism who presented acutely encephalopathic with deranged thyroid function who responded well to steroids and made a full recovery; previously described in adult cases. Case 2 13-year-old boy with acute, severe short-term and long-term memory loss, stroke like episodes and generalised seizures over the course of three different admissions in a 1-month period. He subsequently developed focal status epilepticus, unilateral hippocampus changes which progressed to bilateral on MRI. Antibody testing revealed a diagnosis of Hashimoto9s encephalitis. He had four cycles of plasmapheresis after immunoglobulin infusions, remains on high-dose steroids. The initial response to this treatment was excellent but after 6 months he continued to have episodes of deterioration in memory function and has started on retuximab for immunomodulation in addition to high-dose oral steroid. This combination of treatment has stabilised his memory function and he has now returned to school on a part-time basis. Conclusion The presentation of case 1 is well recognised in the literature in adult patients with established thyroid disease. In case 2 our patient developed focal status epilepticus which has not been recognised as a feature of Hashimoto9s encephalitis in the literature. He is also responding to a new form of immunomodulation medication which has previously never been described; most cases in the literature have used azathioprine as a second-line agent. Both patients had an encephalopathy related to antithyroid antibodies but their history, signs and symptoms highlight the spectrum of presentations that these patients can have as well as the varied clinical response to treatment. The authors feel presenting the above cases with an overview of current literature will aid clinical practice and would be grateful for the opportunity to highlight the spectrum if disease associated with antithyroid antibodies.