When do generalized tremors occur?

When Generalized Tremors Occur

Generalized tremors most commonly occur in orthostatic intolerance syndromes, during seizures, as part of Parkinson's disease and other movement disorders, or as a manifestation of drug/medication effects or withdrawal. These tremors involve multiple body parts simultaneously rather than being limited to a single region.

Types of Generalized Tremors and Their Occurrence

1. Orthostatic Intolerance-Related Tremors

• Occur when standing upright
• Present in conditions like:
  • Orthostatic hypotension (OH) 1
  • Postural Orthostatic Tachycardia Syndrome (POTS) 1
  • Characterized by:
    • Tremulousness
    • Generalized weakness
    • Often accompanied by lightheadedness, palpitations, and blurred vision
    • Typically relieved by sitting or lying down

2. Seizure-Related Generalized Tremors

• Occur during generalized tonic-clonic seizures 1
• Present as:
  • Full-body rhythmic jerking
  • Accompanied by alterations in consciousness
  • May be preceded by an aura in some cases
  • Often followed by postictal confusion
• Seizures may be:
  • Unprovoked (epileptic) 1
  • Provoked by acute insults (within 7 days) 2

3. Movement Disorder-Related Tremors

• Parkinson's Disease tremors 1:

  • Initially asymmetric and at rest
  • Can become more generalized as disease progresses
  • Typically 4-6 Hz frequency
  • Increase during stress 3

• Essential Tremor 4:

  • Most common pathologic tremor (affects 0.4-6% of population)
  • Action tremor (occurs during voluntary movement)
  • Often involves hands, head, and voice
  • Can appear generalized in advanced cases

4. Drug and Toxin-Related Tremors

• Medication-induced tremors:

  • SSRIs (selective serotonin reuptake inhibitors) 1
  • Stimulants (caffeine, amphetamines) 1
  • Withdrawal from sedatives (benzodiazepines, alcohol) 1

• Alcohol withdrawal tremors 1:

  • Occur 3-12 hours after cessation
  • Can last up to 18 months
  • Accompanied by hyperactivity, irritability, poor sleep

5. Whole-Body Tremulousness (Polymyoclonus)

• Can be mistaken for generalized tremor 5
• Characterized by:
  • Nonperiodic muscle bursts <50 milliseconds
  • Affects all limbs
  • Often impairs gait
  • May be associated with:
    • Autoimmune conditions
    • Paraneoplastic syndromes
    • Medication effects (opioids, SSRIs)

Clinical Differentiation of Generalized Tremors

Activation Conditions

• Rest tremors: occur when body part is relaxed and supported 4

  • Characteristic of Parkinson's disease
  • Decrease with voluntary movement

• Action tremors: occur with voluntary muscle contraction 4

  • Postural: maintaining position against gravity
  • Kinetic: during voluntary movement
  • Isometric: during muscle contraction against fixed object

Frequency Characteristics

• Physiologic tremor: high frequency (8-12 Hz), low amplitude 6
• Parkinsonian tremor: 4-6 Hz 3
• Essential tremor: 4-12 Hz 4
• Cerebellar tremor: 2-4 Hz, intention tremor 4

Important Considerations

1. All tremors cease during sleep 6

2. Stress can significantly affect tremor characteristics:

   • In Parkinson's disease, stress increases both tremor amplitude and frequency 3
   • Peak frequencies tend to concentrate around 5 Hz under stress

3. Distinguishing true tremor from polymyoclonus is important:

   • Tremor has rhythmic oscillatory movements
   • Polymyoclonus has brief (<50ms) muscle bursts that may appear as generalized tremulousness 5

4. Generalized tremors in orthostatic conditions may be accompanied by:

   • Dizziness, weakness, fatigue
   • Palpitations
   • Visual disturbances
   • Pallor and sweating 1

When evaluating generalized tremors, careful attention to the context in which they occur, associated symptoms, and activation conditions can help determine the underlying cause and guide appropriate management.