Tremor
What is it?
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.
This information has been designed as a comprehensive and quick reference
guide written by our health care reviewers. The health information written
by our authors is intended to be a supplement to the care provided by your
physician. It is not intended nor implied to be a substitute for
professional medical advice.
|
