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 tremorTremor.
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.
Primidone: initial dose 30 mg (1/8 of a 250 mg tablet), may be increased up to 500 mg per day, taken usually in the evening (may require special license)