A 45-year-old woman comes to the office due to tremor in her hands. She has had an on-and-off tremor for several years, especially when she becomes stressed; however, over the past 6 weeks, the tremor has persisted and become more severe. The patient has no other symptoms. Medical history is significant for generalized anxiety disorder, for which she has been taking sertraline for 2 months. The patient does not drink alcohol. There is no family history of tremor or neurologic conditions. Temperature is 36.8 C (98.2 F), blood pressure is 130/84 mm Hg, pulse is 82/min, and respirations are 16/min. Physical examination shows a high-frequency tremor of both hands that is prominent with finger-to-nose testing. The tremor is not relieved with distraction. The remainder of the examination is normal. Complete blood count, serum chemistry profile, and serum TSH are normal. What is the most likely diagnosis?

Question

A 45-year-old woman comes to the office due to tremor in her hands.  She has had an on-and-off tremor for several years, especially when she becomes stressed; however, over the past 6 weeks, the tremor has persisted and become more severe.  The patient has no other symptoms.  Medical history is significant for generalized anxiety disorder, for which she has been taking sertraline for 2 months.  The patient does not drink alcohol.  There is no family history of tremor or neurologic conditions.  Temperature is 36.8 C (98.2 F), blood pressure is 130/84 mm Hg, pulse is 82/min, and respirations are 16/min.  Physical examination shows a high-frequency tremor of both hands that is prominent with finger-to-nose testing.  The tremor is not relieved with distraction.  The remainder of the examination is normal.  Complete blood count, serum chemistry profile, and serum TSH are normal.  What is the most likely diagnosis?

Quizplus · Accepted Answer

Explanation: 11ec25c8_d583_2064_bc81_034f084303be_MD0003_00 This patient has a history of an intermittent, high-frequency action tremor of the hands that worsens with stress, findings consistent with a physiologic tremor. Most individuals have a fine (ie, low-amplitude, high-frequency) action tremor of the hands, which is considered physiologic and is usually visible only in the settings of increased sympathetic activity (eg, caffeine, hyperthyroidism, anxiety). The worsening of the tremor after the patient began sertraline suggests that it is enhanced by the addition of a selective serotonin reuptake inhibitor (SSRI). Certain medications are associated with enhancement of a physiologic tremor (eg, beta agonists, corticosteroids), which is most often due to an increase in adrenergic activity. However, up to 20% of patients using SSRIs develop an enhanced physiologic tremor, possibly due to serotonergic stimulation of the cortical and thalamic nuclei. The following characteristics support a diagnosis of a medication-enhanced tremor: Temporal relationship to initiation of the medication Dose-response relationship Lack of tremor progression Symmetry of the affected limbs In patients with suspected medication-enhanced physiologic tremors, dose reduction or stoppage of the offending medication can be both diagnostic and therapeutic. (Choice A) Although cerebellar tremors are action tremors, they are classically low frequency (<5 Hz) and high amplitude and increase as an action approaches a target. In addition, they are typically accompanied by other cerebellar signs (eg, ataxia, dysmetria, impaired rapidly alternating movements). (Choice B) SSRIs (eg, sertraline) can rarely cause dystonia. Dystonic tremors may present as irregular tremors exacerbated by stress. However, they occur with sustained muscle contractions (eg, wrist spasms, torticollis), typically in the same area as the tremor. (Choice D) Functional (psychogenic) tremors usually present as high-amplitude, low-frequency tremors that occur inconsistently and are associated with significant disability. They often improve with distraction. (Choice E) In contrast to this patient with medication-enhanced physiologic tremor, patients with Parkinson disease classically have a resting tremor that improves with intentional movement. In addition, tremor is accompanied by rigidity, bradykinesia, and gait disturbances. Educational objective: An enhanced physiologic tremor is typically a fine, fast, symmetric action tremor of the hands that increases with sympathetic activity. Certain medications (eg, selective serotonin reuptake inhibitors, beta agonists) can cause enhanced physiologic tremor, which generally improves with dose reduction or medication cessation. References: Insights into pathophysiology from medication-induced tremor. (http://www.ncbi.nlm.nih.gov/pubmed/29204312)

A 45-Year-Old Woman Comes to the Office Due to Tremor