Pseudo-Orthostatic Tremor in Graves' Disease: A Possible Early Sign of Parkinsonism?

BACKGROUND

Pseudo-orthostatic tremor is a hyperkinetic movement disorder usually associated with other neurological comorbidities, mainly Parkinson's disease.

CASE REPORT: A 65-year-old male presented with unsteadiness and leg tremor while standing. Electrophysiological evaluation confirmed the presence of pseudo-orthostatic tremor. Blood test showed an undiagnosed Graves' disease. A complete remission of tremor was achieved with methimazole. Dopamine transporter scintigraphy showed a mild reduction of the striatal binding, bilaterally.

DISCUSSION: Graves' disease can be associated with pseudo-orthostatic tremor. Thyroid function should be assessed in patients complaining of unsteadiness. The causative role of hyperthyroidism in determining dopaminergic degeneration and uncovering subclinical parkinsonism warrants further investigations.