Which tremor is classically associated with hyperthyroidism?

• A. Fine resting tremor
• B. Resting tremor with cogwheeling
• C. Intention tremor
• D. Postural tremor

Answer: (A)

Hyperthyroidism commonly causes a fine, high-frequency tremor of the hands that is most evident when the hands are at rest. This resting tremor reflects increased adrenergic activity and heightened motor neuron excitability in thyrotoxicosis. It’s a small-amplitude tremor, not the larger, goal-directed tremors seen with cerebellar disease or the rigid, cogwheel tremor of Parkinson’s. Postural tremor seen in essential or physiologic tremor isn’t the classic pattern for hyperthyroidism, and intention tremor points to cerebellar dysfunction. So, the hallmark here is a fine resting tremor.