Tremor is an involuntary, rhythmical, shaking movement, usually of the hands, lower arms, and head.
Who gets it?
Tremor occurs as a symptom of some neurological diseases, such as Parkinson’s disease and multiple sclerosis, and in people with diseases of or damage to the cerebellum. Some people inherit this condition from a parent who has tremors, or develop it as a side effect of certain drugs or underlying disease. Tremor can affect both men and women.
What causes it?
Tremor occurs when the muscles relax and contract repeatedly. While most people experience a tremor at some time, usually because of fear or excitement, a number of neurological diseases that destroy nerve tissue cause uncontrollable tremor. These include Parkinson’s disease and multiple sclerosis. Other causes include stroke or head injury; Wilson’s disease, a hereditary disorder in which toxic levels of copper accumulate in the tissues; mercury poisoning; an over-active thyroid gland; and liver encephalopathy. Tremor can occur as a side effect of drugs including amphetamines, antidepressants, antipsychotics, caffeine, and lithium, and as a result of withdrawal from alcohol or addictive drugs. Tremors are classified according to the type of shaking, how often it occurs, and how severe it is. A tremor that gets worse when a person is moving is called an intention tremor. Intention tremors signal a problem in the cerebellum, the part of the brain responsible for movement, balance, and coordination. These usually occur in people with multiple sclerosis, who have had a stroke, or suffer from alcoholism. Essential tremors are a type of tremor that begin in early adulthood and have no known cause. When essential tremors begin in older people, they are called senile tremors. Research has shown that essential tremor is in an inherited condition in over 50 percent of all cases. Children of a parent with essential tremor have a 50% chance of also having this condition. Essential tremors do not indicate any underlying disease. Tremors that occur when the muscles are at rest may be a sign of Parkinson’s disease. These types of tremors are called resting tremors or Parkinsonian tremors.
What are the symptoms?
Intention tremors are slower types of tremors, so the movements look broader and coarse. Intention tremors can occur at rest, but usually increase with activity. Essential tremors, however, are fairly quick, small movements. Essential tremor most commonly affects the head and hands, but it may also affect other muscles. However, unless the tremor is very severe, the hands and arms usually do not shake when they are at rest. While essential tremors usually remain mild, they can be a source of embarrassment because they can affect the person’s ability to write and eat. Essential tremors usually worsen when the person is stressed, tired, anxious, or affected by caffeine or other stimulants. Essential tremors can affect one side of the body more than the other, and may cause the voice to shake if they affect the vocal cords. The type of tremor that is common with Parkinson’s disease is more severe, with as many as four to five muscle movements per second. Parkinsonian tremors occur at rest, but slow down or go away altogether when the person moves.
How is it diagnosed?
Your doctor will take a complete medical history and perform a physical examination. There is no specific test for essential tremor and it is usually easy to diagnose simply by exam and medical history. However, if your doctor suspects the tremor is caused by an underlying condition, he or she may order some diagnostic tests, such as a computed tomography (CT) scan or magnetic resonance imaging (MRI), to check brain function. He or she may order blood tests to check for other causes as well.
What is the treatment?
There is no cure for tremor and, in most cases, there is no need to treat essential tremor. However, severe tremor can be reduced with drug treatment. A drug called propranolol is often used to treat severe essential tremor. However, this drug can have side effects that affect the heart, so its use must be monitored carefully. Other drugs used to treat essential tremor include primidone and benzodiazepine. People with Parkinson’s disease have had success with levodopa or other antiparkinson drugs. Botulinum toxin A has been found effective in treating head, hand, and voice tremors. Botulinum is a bacterium that causes food poisoning (botulism), but causes the muscles to relax when used in a weak solution. Discuss all the possible side effects of botulinum toxin A with your doctor before trying this treatment. Another technique for controlling severe tremor involves using mild electrical pulses to stimulate the brain. A surgeon implants an electrode in the area of the brain where nerve impulses are relayed and movement is generated. A wire from the electrode follows a path under the skin from the skull to a small generator implanted in the chest. The patient turns on the generator with a hand-held magnet to deliver an electronic pulse to the brain, which blocks the brain signals that trigger tremor. This treatment is not effective for everyone, so it is important to discuss this option thoroughly with your doctor. Other surgical procedures for patients with severe tremor include thalamotomy, in which the surgeon destroys part of the thalamus; and pallidotomy, in which the surgeon destroys part of a small structure within the brain called the globus pallidus internus. Pallidotomy is sometimes used to treat tremors from Parkinson’s disease. Both of these surgical techniques destroy portions of the brain that affect movement, and may have negative side effects concerning balance and coordination. Stem cell transplantation, in which fetal tissue is implanted in a patient’s brain to replace malfunctioning nerves, is an ongoing source of controversial research but has shown some promise in treating conditions such as Parkinson’s disease.
Self-care tips
While tremor itself is not life-threatening, it can be a nuisance. While there is no way to prevent essential tremor and certain neurological diseases that cause tremor, you can take steps to reduce tremor. Avoid stimulants such as caffeine and amphetamines. While small amounts of alcohol may reduce tremor, avoid drinking large amounts of alcohol, which can make tremor worse.
The source of this information is http://www.hmc.psu.edu/healthinfo/t/tremor.htm