Erratic movement disorders disclosing Graves’ disease and paralleling thyroid function but not autoantibody levels

Abstract

Graves’ disease (GD) is an autoimmune pathology characterized by hyperthyroidism and the presence of specific anti-thyroid antibodies. Neurological symptoms such as seizures, cognitive impairment, and tremor can be observed during the course of GD, but more complex movement disorders such as chorea and myoclonus are less frequent. The mechanisms underlying movement disorders in GD are not fully understood. While some authors relate movement disorders to thyroid dysfunction, others claim an autoimmune origin. We herein report a case involving a 60-year-old woman who presented with erratic, intricate movement disorders for which a medical workup revealed GD. During the 2-year follow-up period, her neurological symptoms evolved in parallel with her thyroid function, but not with her autoimmune anti-thyroid antibody level. Her neurological symptoms completely disappeared when she became euthyroid. We herein discuss the complicated clinicobiological relationship between thyroid function and movement disorders. This relationship involves several factors, including the impact of radioactive treatment. The present case emphasizes the importance of including thyroid function screening in the workup of unexplained movement disorders.

Thyroid Disorders and Movement Disorders—A Systematic Review

“…Complex phenotypes have also been observed, eg, complex dyskinesia, with prominent high‐amplitude myoclonic jerks, ataxia, mild chorea and associated postural tremor. 118 , 119 Behavioral, emotional or psychiatric disorders, weakness, myopathy and other neurological signs and symptoms may be associated signs.…”

Neurologic Complications of Endocrine Disorders

“…Chorea and myoclonus have also been reported in patients with thyrotoxicosis, although they are far less common than tremor. 61 These hyperkinetic movement disorders typically improve with beta-blocker therapy and with treatment of the hyperthyroid state.…”

“…A fine postural tremor similar to that of essential or enhanced physiologic tremor is a common manifestation of hyperthyroidism and is likely exacerbated by β-adrenergic hyperactivity. Chorea and myoclonus have also been reported in patients with thyrotoxicosis, although they are far less common than tremor 61 . These hyperkinetic movement disorders typically improve with beta-blocker therapy and with treatment of the hyperthyroid state.…”