What are the different types of tremors and their treatments?

Types of Tremor and Their Treatments

Tremors can be classified into several distinct types based on their clinical presentation, with each type requiring a specific treatment approach tailored to its underlying pathophysiology.

Classification of Tremors

1. Rest Tremor

• Occurs when the affected body part is completely supported against gravity and not actively contracting
• Most commonly associated with Parkinson's disease
• Typically 4-6 Hz frequency
• Often presents as "pill-rolling" tremor of the hands
• Treatment: Levodopa/carbidopa is the first-line treatment for parkinsonian tremor 1

2. Action Tremors

These occur during voluntary muscle contraction and include:

a. Postural Tremor

• Occurs when maintaining a position against gravity (e.g., outstretched arms)
• Includes:
  • Essential Tremor (ET): 4-8 Hz, bilateral, often involves hands and head
  • Enhanced Physiological Tremor: Exaggeration of normal tremor due to medications, anxiety, thyroid disorders
  • Dystonic Tremor: Associated with abnormal posturing
  • Medication-Induced Tremor: From beta-agonists, valproate, lithium, SSRIs

b. Kinetic Tremor

• Occurs during voluntary movement
• Includes:
  • Intention Tremor: Worsens as approaching a target (cerebellar pathology)
  • Task-Specific Tremor: Only during specific activities (e.g., writing tremor)

c. Isometric Tremor

• Occurs during muscle contraction against stationary objects

Specific Tremor Types and Their Management

Essential Tremor

• Most common tremor disorder
• Bilateral, postural and kinetic tremor (4-8 Hz)
• Often affects upper extremities and head
• Treatment:
  • First-line: Propranolol (40mg twice daily, up to 240mg daily) 2
  • Alternative: Primidone (starting at 12.5-25mg and gradually titrating) 2
  • For refractory cases: MR-guided focused ultrasound (MRgFUS) thalamotomy or deep brain stimulation (DBS) 3

Parkinsonian Tremor

• Rest tremor (4-6 Hz)
• Often asymmetric
• Treatment:
  • First-line: Levodopa/carbidopa 1
  • Alternative: Dopamine agonists like ropinirole 4
  • Advanced cases: DBS of the subthalamic nucleus or globus pallidus

Wilson's Disease Tremor

• "Wing-beating" tremor: coarse, irregular proximal tremulousness
• Can present with dystonia, dysarthria, and psychiatric symptoms
• Treatment: Copper chelation therapy with penicillamine or trientine 3

Cerebellar Tremor

• Intention tremor that worsens near target
• Associated with ataxia
• Treatment:
  • Limited pharmacological options
  • Isoniazid may help in multiple sclerosis-related cerebellar tremor 5
  • Weighted devices may improve function

Medication-Induced Tremor

• Postural tremor similar to enhanced physiological tremor
• Treatment:
  • Discontinue offending medication if possible 2
  • If medication cannot be discontinued: propranolol (40mg twice daily) 2

Psychogenic Tremor

• Variable frequency and amplitude
• Decreases with distraction
• Treatment:
  • Cognitive behavioral therapy
  • Address underlying psychiatric condition

Treatment Algorithms

For Essential Tremor:

1. Start with propranolol 40mg twice daily (if no contraindications)
2. If ineffective or contraindicated, try primidone starting at 12.5-25mg
3. For inadequate response, consider gabapentin (300-2400mg daily) 2
4. For severe, medication-refractory cases, evaluate for surgical options:
   • MRgFUS thalamotomy (56% tremor improvement maintained at 4 years) 3
   • DBS (approximately 90% tremor control) 2

For Parkinsonian Tremor:

1. Start with levodopa/carbidopa
2. If inadequate response, add or switch to dopamine agonist (ropinirole)
3. For medication-refractory tremor, consider DBS

For Medication-Induced Tremor:

1. Discontinue offending medication if clinically possible
2. If medication cannot be discontinued, start propranolol 40mg twice daily
3. Consider alternative beta-blockers (metoprolol, atenolol) for patients with respiratory concerns 2

Special Considerations

• Isolated head tremor is more likely to be dystonic rather than essential tremor 6
• Voice tremor may respond to botulinum toxin injections 6
• Elderly patients should start with lower doses of medications (e.g., propranolol 10-20mg twice daily) 2
• Patients with respiratory conditions should avoid propranolol; consider metoprolol or non-beta blocker options 2
• Comorbid conditions may guide treatment choice (e.g., gabapentin for patients with neuropathic pain) 2

By accurately identifying the type of tremor and following these treatment algorithms, clinicians can effectively manage most tremor disorders and significantly improve patients' quality of life.