A 50-year-old man comes into the clinic complaining of trembling in his hands, which has been worsening over the last five years. He reports that the trembling decreases when he drinks glass of wine each night. His father and brother have similar tremors. On physical examination, he has a high frequency, bilateral tremor when he extends his hands to reach for an object. No other neurologic signs are noted. He is prescribed propranolol, which improves his symptoms.
Which of the following is the most likely diagnosis?
- A) Dystonia
- B) Essential tremor
- C) Hemiballismus
- D) Intention tremor
- E) Parkinson disease
B) Essential tremor
Essential tremor classically involves the hands and is brought out by arm movement and sustained antigravity postures. The tremor is absent when the affected body part is completely relaxed and supported against gravity. Essential tremor tends to be slowly progressive and affects activities such as writing and drinking from a glass. It can also involve the head, voice, and uncommonly the legs. Essential tremor is typically bilateral, involves an action tremor, is moderate to high in frequency, does not have other neurologic signs present, and is typically relieved by small amounts of alcohol. The most effective treatments are propranolol or primidone.
Answer choice A: Dystonia, is incorrect. Dystonia is characterized by involuntary, sustained muscle contractions that result in jerking movements.
Answer choice C: Hemiballismus, is incorrect. Hemiballismus occurs when there is a lesion in the subthalamic nucleus. It is marked by sudden, flailing movements in the contralateral arm and leg.
Answer choice D: Intention tremor, is incorrect. Intention tremor is due to a cerebellar defect and is characterized by a slow, large amplitude tremor when pointing at a target. It would not improve with alcohol or propranolol.
Answer choice E: Parkinson disease, is incorrect. The tremor of Parkinson's disease is a resting, "pill-rolling" tremor that is relieved with movement.
Key Learning Point
Essential tremor is the most common adult movement disorder. Essential tremor classically involves the hands and is brought out by arm movement and sustained antigravity postures. The tremor is absent when the affected body part is completely relaxed and supported against gravity. Other neurologic sings are absent.