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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
- 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
- Medications can be used as needed, but in the most severe cases continuous use is often required.
- Non-selective beta-blockers
- 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]