Objective: We report the case of a woman with chorea as lonely feature

Background: Hashimoto encephalopathy is a rare autoimmune and vasculitis encephalopathy.  The first case is described in 1966 by Brain and al. The neurologic and psychiatric disorders are not specific.

Method: 68years old woman, tobacco dependance with a personal pathological history of hypothyroid treated by levothyroxine and stopped in the past three months. No family history of chorea. Progressive onset over 1 month oh hyperkinetic movement disorders and dysarthria. The clinical exam notes generalized chorea. No Parkinsonism and any evident psychiatric nor cognitive disorders (MMSE = 29/30). Brain MRI [figure 1], TAP scan, EEG are normal. Slight elevated CSF proteins (0,57 G/L) with no pleocytosis. Negative auto antibodies. TPO antibodies >1000 /ml (N<35) and anti-thyroglobulin antibodies (anti-TG) = 793,6 U/mL (N<40). No evidence for infectious, vascular, metabolic, neoplastic or paraneoplastic disorder.

No clinical improvement with haloperidol and correction of hypothyroidy. Spectacular improvement with corticosteroid (methylprednisolone 80 mg/day). 

The patient presented corticosteroid-induced myopathy and osteoporosis fracture at the third month of treatment. 

The corticosteroid is replaced by azathioprine.

Results: The clinical onset may be sudden or progressive and concern all neurological functions. In our case it was about a movement disorder. Clinical manifestations are independent of thyroid hormone levels (generally normal). But they depend on thyroid antibodies levels according to some authors. High levels of thyroid antibodies are essential for the diagnosis [1 ; 2]. 

The EEG is usually abnormal. Brain MRI is generally normal. The is no specific marker of the disease. It is a diagnosis of exclusion. [1 ; 2]. 

There are many diagnosis criteria without consensus [4 ; 5 ; 6]. 

The response to corticosteroid and plasmapheresis is variable [7].

The long-term prognosis is good (93% of cases). The are relapses in one year follow up (16% of cases). Delay in diagnosis leads to neuro-cognitive sequelae [1 ; 8].

Conclusion: Hashimoto encephalopathy is a rare condition due to high levels of thyroid antibodies. the pathophysiology is not well-known. The diagnosis is difficult because of clinical, biological and radiological polymorphism. An international and multidisciplinary diagnostic criteria is necessary to refine the diagnosis.

Brain MRI sequence DWI : normal

References: 1. Chaudhuri J, Mukherjee A, Chakravarty A. Hashimoto’s Encephalopathy: Case Series and Literature Review. Curr Neurol Neurosci Rep. 2023 Apr;23(4):167-175.

2. Ralli M., Angeletti D., Fiore M., et. al.: Hashimoto’s thyroiditis: an update on pathogenic mechanisms, diagnostic protocols, therapeutic strategies, and potential malignant transformation. Autoimmun Rev 2020; 19: pp. 102649.
3. Mattozzi S., Sabater L., Escudero L., et al: Hashimoto encephalopathy in the 21st century. Neurology 2020; 94: pp. e217-e224
4. Castillo P, Woodruff B, Caselli R, Vernino S, Lucchinetti C, Swanson J, Noseworthy J, Aksamit A, Carter J, Sirven J, Hunder G, Fatourechi V, Mokri B, Drubach D, Pittock S, Lennon V, Boeve B. Steroid-responsive encephalopathy associated with autoimmune thyroiditis. Arch Neurol. 2006 Feb;63(2):197-202.

5. Tamagno G, Federspil G, Murialdo G. Clinical and diagnostic aspects of encephalopathy associated with autoimmune thyroid disease (or Hashimoto’s encephalopathy). Intern Emerg Med 2006, Vol 1 No 1.

6. Graus F, Titulaer MJ, Balu R, Benseler S, Bien CG, Cellucci TJ. A clinical approach to diagnosis of autoimmune encephalitis. Lancet Neurol. 2016;15:391–404. doi: 10.1016/S1474-4422(15)00401-9.

7. Cook M.K., Malkin M.,and Karafin M.S.: The use of plasma exchange in Hashimoto’s encephalopathy: a case report and review of literature. J Clin Apher 2015; 30: pp. 188-192.

8. Link J., and de Vries T.W.: Unexplained seizures, confusion or hallucinations: think Hashimoto encephalopathy. Acta Peadiatr 2008; 97: pp. 451-453.

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