What is the best course of action for an older adult with no significant medical history presenting with resting tremors?

Evaluation and Management of Resting Tremor in Older Adults

A unilateral resting tremor in an older adult should be immediately evaluated for Parkinson's disease and treated with levodopa/carbidopa 25/100 mg three times daily, titrated based on response. 1, 2

Initial Diagnostic Assessment

Determine tremor characteristics through focused examination:

• Resting tremor (present when hand is fully supported against gravity, disappears with voluntary movement) strongly indicates Parkinson's disease, which typically begins asymmetrically and unilaterally 1, 2, 3

• Action/postural tremor (occurs during tasks or maintaining posture) suggests essential tremor or enhanced physiologic tremor instead 2, 4, 5

• Variable frequency, amplitude, and direction with sudden onset in context of stress suggests functional/conversion tremor 1, 2, 4

Key clinical features to assess:

• Timing of onset: gradual favors Parkinson's disease; sudden onset suggests functional tremor 2

• Family history: positive family history points toward essential tremor rather than Parkinson's disease 2

• Entrainability: tremor that changes with voluntary rhythmic movements of other body parts is characteristic of functional tremor 1

Medication Review

Review and discontinue potentially causative medications before proceeding:

• SSRIs, TCAs, MAOIs can exacerbate tremor 1
• Stimulants and antipsychotics should be stopped before starting tremor medications 2, 4

Imaging Considerations

No routine imaging is required for typical unilateral resting tremor consistent with Parkinson's disease. 1, 2, 4

Brain MRI is indicated only if:

• Atypical features suggest structural lesions 1, 4
• Evidence of abnormal neurologic activity beyond typical Parkinson's disease features 1
• Suspicion for atypical parkinsonism (early falls, vertical gaze palsy, prominent autonomic dysfunction, cerebellar signs) 1

Treatment Algorithm

For Parkinsonian Resting Tremor:

First-line: Levodopa/carbidopa is the most effective symptomatic treatment for all parkinsonian motor symptoms including tremor. 1, 4

• Start at 25/100 mg three times daily 1
• Titrate based on response 1
• Significant improvement with levodopa trial serves as both diagnostic confirmation and therapeutic intervention 2, 4

Alternative first-line options:

• Anticholinergics may be used for parkinsonian tremor 3, 6

Refractory cases:

• Deep brain stimulation (DBS) should be considered when medical therapies fail at maximum tolerated doses 1
• MRI-guided focused ultrasound (MRgFUS) thalamotomy is effective for unilateral tremor causing significant functional impairment 1

For Essential Tremor (if action/postural tremor instead):

• Propranolol 80-240 mg/day is first-line therapy 4, 6, 7
• Primidone is equally effective as first-line therapy with up to 70% response rate 4, 3

For Functional Tremor:

• Non-pharmacological interventions are primary: rhythm modification techniques, muscle relaxation, activity modification 1, 4
• Pharmacotherapy has no evidence of benefit for functional tremor 1
• Avoid excessive use of adaptive equipment as aids interrupt rehabilitation and prevent improvement 4

Critical Pitfalls to Avoid

• Do not diagnose essential tremor based solely on unilateral resting tremor—essential tremor is primarily postural/action tremor and typically bilateral 1, 2, 4

• Do not use propranolol for parkinsonian resting tremor—beta-blockers are only effective for essential tremor and enhanced physiologic tremor 1, 4

• Do not assume functional tremor is "psychogenic" or dismiss it—symptoms are involuntary and require specific therapeutic approaches 1, 2

• Do not start tremor medications before discontinuing potentially causative drugs like stimulants or antipsychotics 1, 2, 4

• Do not order extensive imaging for typical presentations—clinical diagnosis based on tremor characteristics is usually sufficient 2, 4