Endocrine Abstracts

Introduction: We report a case of a young man who presented with severe cerebellar dysfunction, widespread choreiform movements and thyrotoxicosis. A rare diagnosis of Encephalopathy Associated with Autoimmune Thyroid disease (EAATD) linked to Graves’ disease was made, a condition usually described in association with Hashimoto’s thyroiditis

Case: A 26-year-old male presented with acute severe ataxia and dysarthria. Examination revealed widespread signs of cerebellar dysfunction, hyperreflexia, choreiform movements and bilateral saccadic pursuit. Cognition was intact and there were no bulbar or meningeal signs. T3 10.4pmol/l, T4 38.3pmol/l TSH<0.008mU/l, TSH-receptor antibodies (TRAB) 35.14IU/l and anti-TPO antibodies 790.6kIU/l. MRI brain, EEG, CSF, autoimmune screen and ACE were normal excluding other relevant differential diagnoses. In view of the temporal association with hyperthyroidism, a diagnosis of EAATD was made, jointly with neurologists. He was treated with 40 mg carbimazole and IV methylprednisolone (1gmx3) followed by 60 mg prednisolone. Over the next 4 weeks, he demonstrated rapid recovery with no neurological sequelae and TRAB down to 17IU/l. Prednisolone was tapered off over 8 weeks and he remains on carbimazole.

Discussion

EAATD is rare, and described in association with Hashimoto’s thyroiditis, whereas reports in association with Graves’ are even rarer. Diagnosis is made by excluding relevant systemic conditions, and rapid response to steroids along with improvement of thyroid biochemistry. Although several possible mechanisms are described the exact pathogenesis remains unclear. Uncommon features demonstrated by our case were male gender and predominant cerebellar involvement with absence of seizures, abnormalities of cognition and normal CSF, all indicating focal neurological involvement. We also demonstrated post-therapy decline in TRAB in parallel with clinical improvement, not described previously.

Conclusion: EAATD with acute cerebellar syndrome and choreiform movements can be presenting features of Graves’ hyperthyroidism and the diagnosis should be considered in patients with this combination especially since early therapy can lead to complete recovery.