Familial tremor

Familial tremor is a neurologic disorder that tends to run in families, involving involuntary shaking (tremors) that typically gets worse when the affected person tries to move or become more active.

Causes, incidence, and risk factors

There is overlap between essential tremor, which may occur as an isolated case but may also run in families, and familial tremor, which affects more than one person in a family. Tremors can affect people at any age, but they are most common in older people.

A familial tremor is usually a relatively benign condition, affecting movement or voice quality but seldom having any other effects. It involves a rhythmic, moderately rapid tremor (shaking) of voluntary muscles.

Purposeful movements may make the tremors worse. There may be difficulty holding or using small objects (such as eating or writing utensils). Emotional stress may also increase the tremors.

Over time, the tremors may affect the hands, arms, head, voice box (larynx), eyelids, or other muscles, but they rarely involve the legs or feet. In children, these tremors are usually limited to the hands and rarely require treatment.

The exact cause is unknown, but the fact that it is inherited suggests a genetic cause. It is usually dominant, which means about 50% of an affected person's children will be affected.

If you inherit one copy of the gene from either parent, you will have the disorder.

This disorder should not be confused with Parkinson's disease which can also cause tremors and shaking in old age.

Symptoms

• Tremors
  • Occasional (sporadic), temporary (episodic), or ceasing at intervals (intermittent)
  • A rate of about 6 to 10 per second (when tremors are occurring)
  • Affecting the head, hands, arms, eyelids or voice
  • Less commonly affect the lower body
  • May not affect both sides of the body equally
• Tremors that worsen with voluntary movement and emotional stress
• Tremors that disappear during sleep
• Tremors that may improve with alcohol

Signs and tests

Diagnosis is usually made on the basis of the patient's history and an examination that reveals tremors on voluntary movement with no changes in gait or coordination. There are usually no other abnormalities (such as dementia) or changes in mental status or brain function.

No other tests may be required. However, testing may be used to rule out other causes of tremors such as excessive caffeine intake, alcohol withdrawal, medication use, hyperthyroidism, pheochromocytoma, Wilson's disease, or other disorders. Laboratory tests and a head CT scan, MRI, X-rays, angiography, or other tests are usually normal.

Treatment

Treatment may not be necessary unless tremors interfere with the patient's ability to perform daily activities.

Medications are variable because of individual responses to them. Medications that may reduce tremors include propranolol, Mysoline and other anticonvulsants, and mild tranquilizers. If tremors interfere with activity significantly and are not responsive to medication, surgery to implant a deep brain stimulator (DBS) in the basal ganglia may be an option.

Caffeine (in substances such as coffee and soda) and other stimulants should be avoided because they commonly worsen tremors.

Alcoholic beverages in small quantities may markedly decrease tremors, but drinking should be carefully monitored to avoid alcohol abuse and alcohol dependence, especially if there is a family history of alcohol problems. The mechanism by which alcohol ameliorates familial tremor is unknown.

Expectations (prognosis)

A familial tremor is not a dangerous condition, but it can be annoying and embarrassing. If it is severe, it can mildly interfere with activities, especially fine-motor skills such as writing. Feeding yourself can be a problem. Speech is occasionally involved.

References

National Library of Medecine. National Institute of Health. http://www.nlm.nih.gov/medlineplus/ency/article/000763.htm

External Links

• | Worldwide education and awareness for movement disorders