Tremor

Classification

Rest Tremor

Most cases are due to Parkinsonism (although severe Essential Tremor can mimic this)
Patient attempts to maintain body position at rest (despite support against gravity)
Provoked by stress or distraction (e.g. counting backwards) or moving another body part (e.g. walking)
Rest Tremor decreases with voluntary movement

Postural Tremor

Patient attempts to maintain Posture against gravity (stretch hands out in front of them)
Essential Tremor
Physiologic Tremor or Enhanced Physiologic Tremor
Drug-Induced Tremor
Other causes
- Dystonia
- Psychogenic Tremor
- Metabolic Causes of Tremor (esp. Thyrotoxicosis)

Action Tremor

Isometric Tremor: Muscle Contraction against rigid item (e.g. grasping with fist)
Kinetic Tremor: Occurs with any form of voluntary movement
Intention Tremor (subtype of Kinetic Tremor): Tremor amplifies as target is reached, Exercise high index of suspicion for cerbellar lesion
Task-specific tremor (subtype of Kinetic Tremor): Tremor on performing highly skilled activity (e.g. writing, speaking, playing music)

Examination

Characterize Tremor
- Record part of body with Tremor
- Provocative and palliative factors
- Tremor frequency (fast or slow Tremor)
- Tremor amplitude (coarse or fine Tremor)
Observe with hands resting in lap (Rest Tremor)
Observe writing or drinking (Action Tremor)
Perform Finger-Nose-Finger Test (Intention Tremor)
Draw a spiral (Archimedes Spiral in Essential Tremor)
Focus exam based on Tremor type
- Action Tremor
- Postural Tremor
- Rest Tremor

Investigations

Liver Function Tests
Complete Blood Count (CBC)
Thyroid Function Tests
Manage by avoiding provocative factors
- Drug-Induced Tremor
  - Eliminate or reduce dose of offending agent
- Psychogenic Tremor (e.g. relieved with distraction)
Patient under age 40
- Wilson’s DiseasE: Low serum ceruloplasmin and high 24 hour urinary copper
- Associated Neurologic findings = Evaluate with MRI Brain
Patient over age 40

If Rest Tremor
- Parkinsonism likely
- If rigidity, Bradykinesia or postural instability then trial on Parkinsonism treatment
Action Tremor
- Consider Alcohol Tremor
- Postural Tremor
- Essential Tremor
Intention Tremor or Cerebellar Tremor
- Obtain MRI Brain
- Evaluate for Multiple Sclerosis, Cerebrovascular Accident, Brain Tumor

Essential Tremor

Prevalence: 0.4 to 6%
Most common pathologic Tremor cause in world
Age of onset 20-60 years (bimodal distribution)
Likely has onset for most patients in ages 20-30 years but is mild initially
Later presentation at age 60-70 years coincides with the natural progression in severity
Causes
- Genetic (Autosomal Dominant inheritance) in 50% of cases
- Sporadic
First line Medication
- Beta Blocker (preferred)
  - Effective in only 30-50% of Essential Tremor cases
  - Most effective for limb Tremors, but will is also effective in head Tremor
  - Non-selective Beta Blockers (preferred first-line)
    - Propranolol (most commonly used)
    - Daily use: Propranol LA (Inderal) 80-320 mg daily
    - Prn use: Propranolol 10-40 mg every 6 to 12 hours as needed
  - Selective Beta Blockers (alternative in Obstructive Lung Disease)
    - Atenolol
    - Metoprolol (Lopressor)
- Primidone (anticonvulsant)
  - Primidone (Mysoline) 25-750 mg qd
- Topiramate (anticonvulsant)
  - Start 25 mg orally daily and titrate to 100 mg orally daily over 2-4 weeks
Leblhuber (2010) Case Rep Neurol 15;2(1):1-4 +PMID: 20689627 [PubMed]

Palliative factors reducing Tremor
- Alcohol
- Benzodiazepines
- Beta Blockers (e.g. Propranolol)
- Primidone (Mysoline)

Investigations
- Not indicated unless atypical case or severe Tremor
  - Chemistry Panel including Glucose
  - Liver Function Tests
  - Thyroid Stimulating Hormone (TSH)
Management
- Eliminate exacerbating factors
- Essential Tremor
  - Diagnosis of exclusion if other causes excluded
  - Trial on Beta Blocker
- Decrease Caffeine