A 57-year-old man comes to the office due to involuntary shaking of his hands. It started on the right side, but now his left hand shakes as well. The shaking disappears with purposeful activity and worsens with emotional stress. He does not have a family history of tremors. Physical examination reveals a resting hand tremor with a frequency of 5-7 cycles/sec. There is some muscle rigidity of both arms. His gait and posture are normal. His mini mental status exam yields a score of 30/30. Which of the following is the most appropriate treatment for this patient?

Question

A 57-year-old man comes to the office due to involuntary shaking of his hands.  It started on the right side, but now his left hand shakes as well.  The shaking disappears with purposeful activity and worsens with emotional stress.  He does not have a family history of tremors.  Physical examination reveals a resting hand tremor with a frequency of 5-7 cycles/sec.  There is some muscle rigidity of both arms.  His gait and posture are normal.  His mini mental status exam yields a score of 30/30.  Which of the following is the most appropriate treatment for this patient?

Quizplus · Accepted Answer

This patient's tremor is likely due to early stage Parkinson disease (PD). The tremor of PD characteristically occurs during rest and improves with activity. (In contrast, essential tremor [ET] has the opposite pattern, making it an unlikely diagnosis in this patient.) Parkinson tremor usually has a frequency of 5-7 Hz, and is often the first manifestation of PD. The tremor often involves one hand before the other or presents asymmetrically. Rigidity is also characteristic of PD. The absence of additional symptoms such as postural instability or gait abnormality should not exclude the diagnosis of PD. A variety of medications can be used in different combinations for the treatment of PD. Of the answer choices listed, the anticholinergic agent trihexyphenidyl is the only appropriate option. Trihexyphenidyl is typically used in younger patients (eg, age ≤65) with tremor-dominant PD. In older patients with mild, tremor-dominant disease, amantadine is sometimes used to avoid the anticholinergic effects of trihexyphenidyl. Otherwise, pharmacologic therapy for PD should be individualized. Monoamine oxidase type B inhibitors have modest antiparkinson effects and are typically used for patients with mild symptoms. Levodopa has potent antiparkinson effects and is typically used for patients with moderate or severe symptoms. In patients age ≤65 with mild to moderate symptoms, dopamine agonists (relatively poorly tolerated in older patients) or levodopa can be considered. (Choices A, B, C, and D) The beta blocker propranolol is considered first-line for the treatment of ET. Primidone (an anticonvulsant) is sometimes used alongside a beta blocker as the combination of the 2 agents is possibly more effective than either alone. Clonazepam may be effective for limb tremor associated with ET, but other medications are preferred due to the abuse potential of benzodiazepines. The effectiveness of clozapine in treating ET is unclear as the data are conflicting. This patient's rest tremor that improves with activity is not consistent with ET. Educational objective: Parkinson disease (PD) should be suspected in patients with a resting tremor of 5-7 Hz that is asymmetric and associated with rigidity. Tremor is often the presenting symptom of PD. Trihexyphenidyl is an anticholinergic medication sometimes used in the treatment of PD, generally in younger patients where tremor is the primary symptom.

A 57-Year-Old Man Comes to the Office Due to Involuntary