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Essential Tremor

Essentials

  • Symmetrical tremor of upper extremities or of the head, accentuated by movement and in raised arms. Psychological stress also intensifies tremor.
  • Often familial
  • Diagnosis is based on physical examination and patient history.
  • Important to differentiate from Parkinson's disease and from other diseases causing tremor on the basis of the clinical picture
  • Beta-blockers, either as needed or continuously, are the most common treatment.

Epidemiology

  • Essential tremor is more common than tremor caused by Parkinson's disease Parkinson's Disease, with a general prevalence of approx. 0.5-1% and in people over 65 years of age 5-6%.
  • Strongly hereditary, but the detection of genetic defects causing the disease has turned out to be difficult. Several genetic defects increasing the risk have been reported.
  • The pattern of inheritance is probably autosomal dominant, i.e., about half of the children may inherit the susceptibility for tremor. The patient's first-degree relatives' risk of developing the condition is 4-5-fold compared to the general population.

Symptoms

  • Tremor is manifested during muscle activation (action tremor) and is rarely present at rest.
  • It is most intense in a static sustentained position, e.g. in extended arms.
  • Tremor usually occurs in both arms quite symmetrically.
  • Tremor may also be seen in the trunk, in the voice and in the head where it is often expressed as turning from side to side ("no-no"-movement; not Parkinson's disease).
  • Psychological stress intensifies tremor which is worst in social situations, e.g. when holding a cup of tea or coffee.
  • Tremor is intensified when skilled acts should be performed (e.g. signature) and is often relieved by ingestion of small amounts of alcohol.
  • Tremor can be quite incapacitating.

Differential diagnosis

  • There are no symptoms typical to Parkinson's disease, such as
    • hypokinesia
    • rigidity.
  • In essential tremor
    • the patient's face is expressive
    • speed of movements is normal
    • muscular tone is normal
    • gait is typically normal or slightly atactic.
  • It may be more difficult to differentiate essential tremor clinically from enhanced physiological tremor Tremor.
  • Differential diagnosis as regards ataxia Ataxia and dystonic tremor should be taken into account.
    • In head tremor, differential diagnosis from cervical dystonia (see Involuntary Movements) may be difficult.
    • Risk of Parkinson's disease is slightly higher in these persons, and sometimes both types of tremor are concomitant.
  • Remember the possibility of hyperthyroidism as the underlying cause of tremor (TSH, free T4).

Treatment

  • The treatment is symptomatic.
  • Non-pharmacological treatments
    • Reduction of coffee consumption (ample consumption of coffee worsens tremor)
    • Adaptation of practices, as applicable, related to home, hobbies and work.
  • Disturbing symptoms may be reduced by pharmacotherapy
  • Botulinum injections are used in some cases (tremor of the head and voice).
    • The decision should be made after careful assessment within specialized care.
  • Neurosurgery (thalamic deep brain stimulation [DBS] or thalamotomy) may be considered in drug-resistant and incapacitating cases.
    • Thalamic stimulator may be inserted bilaterally.
    • Assessment in specialized clinics.

    References

    • Sepúlveda Soto MC, Fasano A. Essential tremor: New advances. Clin Park Relat Disord 2020;3:100031. [PubMed]