Tremor Workup and Management
The appropriate workup for tremor begins with determining the tremor type (rest, postural, kinetic) and associated features, followed by targeted laboratory testing to rule out secondary causes, and treatment should be initiated with propranolol or primidone when tremor causes functional disability. 1
Initial Assessment and Classification
History and Examination
- Determine tremor characteristics:
- Assess associated symptoms:
- Bradykinesia, rigidity (suggests Parkinson's)
- Cerebellar signs (ataxia, dysmetria)
- Red flags: rapid onset, changing characteristics (suggests psychogenic tremor) 2
- Systemic symptoms: weight loss, heat intolerance (thyroid disease)
Laboratory Evaluation
- Basic metabolic panel
- Thyroid function tests
- Liver function tests
- HbA1c
- Consider copper studies (serum ceruloplasmin, 24-hour urinary copper) if Wilson's disease is suspected 1
- Additional tests based on clinical suspicion:
- Drug levels if medication-induced tremor suspected
- Heavy metal screening if exposure history
Imaging
- Brain MRI if:
- Asymmetric or unusual tremor presentation
- Associated neurological signs
- Rapid progression
- Young age of onset
- Consider specialized imaging:
Treatment Algorithm
1. Essential Tremor
- First-line options (approximately 50% effective) 1, 4:
- Propranolol: 40 mg twice daily, max 240 mg daily
- Primidone: Start low (12.5-25 mg) and gradually increase
- Second-line options:
- Alternative beta-blockers: metoprolol, atenolol, nadolol (if propranolol contraindicated)
- Topiramate: 25-400 mg daily
- Gabapentin: 300-2400 mg daily (divided into three doses)
- For refractory cases:
- Combination therapy with propranolol and primidone
- Consider benzodiazepines (clonazepam) for short-term use
- Surgical evaluation if medication fails
2. Parkinsonian Tremor
- First-line: Carbidopa/levodopa 5
- Alternative options:
- Anticholinergics (trihexyphenidyl)
- Dopamine agonists
3. Cerebellar Tremor
- Limited pharmacological options
- Consider isoniazid for cerebellar tremor associated with multiple sclerosis 5
4. Drug or Metabolic-Induced Tremor
- Discontinue offending medication if possible
- Treat underlying metabolic disorder
5. Focal Tremors
- Head or voice tremor: Consider botulinum toxin injections 1
- Hand tremor: Botulinum toxin may help but can cause weakness
Surgical Options for Refractory Tremor
For patients with significant functional disability despite optimal medical therapy:
MR-guided focused ultrasound thalamotomy:
- Indicated for unilateral treatment
- Contraindicated with MRI contraindications or skull density ratio <0.40
- Lower complication rate (4.4%) than other surgical options 1
Deep brain stimulation (DBS) of the thalamus:
- Provides tremor control in ~90% of patients
- Preferred for bilateral procedures
- Higher complication rate (21.1%) than MRgFUS 1
Radiofrequency thalamotomy:
- Effective but higher complication rate (11.8%) than MRgFUS
- Reserved for when DBS or MRgFUS not possible 1
Special Considerations
- Physiologic tremor: Often enhanced by anxiety, caffeine, medications, fatigue - address underlying factors 2
- Psychogenic tremor: Features include abrupt onset, spontaneous remission, changing characteristics, and extinction with distraction 2
- Wilson's disease: Consider in young patients with tremor and liver dysfunction; evaluate with copper studies and look for Kayser-Fleischer rings 3
- Orthostatic tremor: Consider clonazepam; tilt table testing may be useful 1, 5
Treatment Pitfalls
- Don't delay treatment when tremor causes functional disability
- Avoid bilateral thalamotomy due to high risk of complications
- Be aware of beta-blocker contraindications: cardiogenic shock, heart failure, sinus bradycardia, heart block, asthma, reactive airway disease 1
- Remember that no current treatment slows tremor progression 4
- Consider intermittent medication use for situational tremors (e.g., propranolol for stress-induced tremor exacerbations) 4