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ESSENTIAL TREMOR
Tremor refers to
rhythmic shaking of a body part. There are more than 20 kinds
of tremor. Essential tremor (ET) is the most common.
Although called benign essential tremor in the past, it may be far
from benign. Indeed, it may be quite frustrating,
embarrassing, or disabling. People with ET may avoid dining in
restaurants or talking in front of others. They may be tired
of being told they are “nervous” because their voice quivers, or
fear the ordeal of signing a check in public. Fortunately, it
need not be that way. Effective treatments are available for
ET. However, many experts believe that
only a small percentage of people with ET get medical help.
WHAT IS ET?
Essential Tremor is a
very common but complex neurological movement disorder. It is not
caused by another neurological condition or medical side effect.ET
usually affects the hands, but it may also affect the head , neck,
face, jaw, tongue, voice, trunk, and rarely, the legs and feet. The
tremor may be a rhythmic ‘back-and-forth’ or ‘to-and-fro’ movement
produced by involuntary contractions of the muscle. Tremor severity
can vary greatly from hour to hour and day to day. Some people
experience tremor only in certain positions-called postural tremor.
Tremor that worsens while writing or eating is called kinetic
tremor. Most people with ET have both postural and kinetic tremor.
WHAT CAUSES ET?
Essential tremor is due
to abnormal communication between certain areas of the brain,
including the cerebellum, thalamus, and brain stem. In the majority
of people with ET, the tremor seems to be inherited as an autosomal
dominant trait. This means that each child of a parent with ET has
approximately a 50% chance of inheriting a gene that causes ET.
However, not everyone who inherits a gene develops symptoms. Some
people have ET and do not have a family history of tremor,
suggesting the possibility of other causes. Researchers have
already located 2 genes that predispose to ET and are currently
trying to locate others. However, at this time, there is not
genetic test for ET. Identifying genes may allow scientists to find
a cure.
AT WHAT AGE DOES ET
OCCUR?
Though ET may first
appear at any age between childhood and old age, onset is rare
before the age of 10. Most commonly, onset is after age 40, but it
can occur in younger people. Men and women are affected equally,
and in the majority of cases there is a family history of ET. Life
expectancy is no different for people with ET compared to the
general population.
DIAGNOSING ET
Doctors who are trained
to evaluate tremor can accurately diagnose ET on the basis of the
symptoms and a neurological examination. So far, there are no
specific blood, urine, or other tests for ET. ‘Your doctor may want
to investigate other causes of tremor such as thyroid disease,
caffeine excess, or medication side effects. During your physical
exam, your doctor will be gathering as much information as possible
about your tremor. Here are some questions you may be asked:
- What body part is
affected?
- How long have you had
the tremor?
- Did it come on
suddenly?
- What makes your
tremor worse?
- What make your tremor
better?
- Do you drink a lot of
caffeine-containing or alcoholic drinks?
- Do any family members
have tremor?
- Have you ever had a
head injury?
- Does alcohol
temporarily reduce the tremor?
- Does the tremor
worsen when you do certain tasks or when you’re
under emotional stress?
- Does the tremor
disappear during sleep?
-What medication are
you taking? (Certain drugs may cause tremor, so it is a good idea to
bring a list of the medications you are taking.
LOOKING AT THE BRAIN
A brain scan is not
required to diagnose ET. Your doctor might order a magnetic
resonance imaging (MRI) scan or a computerized axial tomography
(CAT) scan if there is suspicion of some other cause of tremor. ET
does not have associated abnormalities on routine scans.
‘ALL THAT SHAKES
ISN’T ET’
Many things cause
tremor, and not all tremors are ET. As mentioned, there are more
than 20 kinds of tremors. For instance, excessive caffeine, alcohol
withdrawal, problems with thyroid or copper metabolism, or the use
of certain medications may cause tremor. A major difference between
ET and other tremor types is that in ET tremor is the only symptom,
and muscle tone, strength, and balance are not usually affected.
OTHER
CAUSES OF TREMOR
Enhanced physiologic
tremor, Parkinson’s disease, Cerebellar tremor, Dystonic tremor, Tremor due to
medications.
Because tremor is a
feature of so many conditions, ET can be mistaken for something
else. Some people have both ET and another disorder that causes
tremor. ET is often confused with some of the conditions listed
above, especially Parkinson’s disease (PD). PD causes a tremor that
occurs at rest, not action. It also causes progressive slowness,
stiffness, and loss of balance. Medications for PD do not help ET
symptoms. Note that many prescription, over-the-counter, and
illicit drugs, as well as some herbal remedies, can cause or worsen
tremor. Tell your doctor about all the medications you are taking.
MEDICATIONS FOR ET
If you have mild ET,
you may not need treatment. There is no evidence that early
treatment stops or slows the natural progression of ET symptoms.
With adequate knowledge, many people learn ways to live well with
ET. If possible, you should be taken off any medications that may
be aggravating tremor. If ET is interfering
with your ability to work or perform daily tasks, or you find it
socially disabling, you may want to consider available therapies.
It is important to have realistic expectations for therapy. At
present, there is no cure for ET. For the oral medications, a 50%
reduction of tremor severity is considered good. The goals of
treatment are to:
- Reduce tremor
severity
- Improve ability to
function
- Decrease social
handicap
Achieving these goals
can sometimes take time, so be patient. While almost two thirds of
people with ET benefit from medical therapies, your doctor may have
to try two to three different medicines before finding the one that
works best for you. The main medication used to treat ET is
propranolol.
PROPRANOLOL (INDERAL)
Propranolol is in a
class of drugs called beta-blockers. Propranolol has been used for
many years, primarily for reducing high blood pressure. It is not
clear exactly how it works in treating ET. Features of propranolol
include the following:
- You may experience
tremor reduction 1-2 hours after taking a single 10-40mg dose of the
short-acting formulation. This effect usually wears off in about 4
hours.
- Propranolol may be
prescribed to be taken as needed, or on a daily basis. A once-daily
long acting preparation is available
- Side effects are
usually mild and are more frequent at higher doses (more than
120mg/day). The main side effects are decreased pulse rate and
blood pressure. Less common side effects are fatigue, depression,
impotence, nausea, weight gain, rash, and diarrhea.
BOTULINUM TOXIN
INJECTIONS
If medications fail,
another therapy may be tried that involves injections of botulinum
toxin into muscles. Botulinum toxin injections have been useful in
the treatment of some patients with head and voice tremors. The
toxin must be placed into target muscles by a trained specialist and
repeat injections may be needed.
THALAMOTOMY
This is a surgical
procedure that involves making a small hole in a part of the brain
called the thalamus. A surgery on one side of the brain produces
it’s effect on the opposite side of the body. The surgery destroys
the faulty circuit or brain cells that modulate tremor. At the
present time, thalamotomy surgery on both sides of the brain is not
recommended as there is an unacceptable risk of loss of speech or
other problems. Approximately 80% of patients have experienced
improvement in tremor after this procedure. When effective,
medications may be reduced or even discontinued. The procedure may
be especially helpful for people with severe hand, arm, or leg
tremors that do not respond to medication.
THALAMIC STIMULATION
Thalamic stimulation is
an alternative to thalamotomy. It involves implanting an electrode
deep in the center of the brain. The electrode is connected to a
stimulation device, similar to a pacemaker, which is placed under
the skin below the collarbone. By sending electrical current
through the electrode, you can interrupt communication between
tremor cells. Tremor reduction occurs within seconds of activation
and can be dramatic. Significant or complete tremor reduction
occurred in approx 80% of people with this procedure. The main
advantages of this procedure are that implanation on both sides of
the brain is possible, the device can be adjusted for optimal
effect, and it may removed, which allows you to keep your options
open in case new therapies develop. The risks are similar to
thalamotomy.
WHO GETS ET?
As many as 1 in 20
people older than 40, and 1 in 5 people older than 65 may have ET.
There may be more than 5 million people with ET in the United
States, and many more world-wide. Essential Tremor is much more
common than most neurologic diseases, with the exception of stroke,
and is more common than Parkinson’s disease.
There are many ways to
minimize the degree to which ET interferes with life and work
- Become informed about
your condition and learn as much as you can about living with ET
- Instead of
restricting your life because of what others may think, explain your
condition simply and honestly
- If your child has ET,
you may want to talk to teachers in person and perhaps pupils in the
class
- Find ways to reduce
stress and learn some relaxation techniques
- Avoid caffeine which
could worsen tremor. Alcohol consumption can temporarily reduce
tremor for a few hours, but it is not an appropriate form of
treatment.
Information taken from
International Tremor Foundation USA
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