Tremor is
a rhythmical shaking of any part of the
body, lasting for at least a few seconds.
It most often affects the hands, the
head, the jaw or the tongue. Tremor is very
common, especially in older people, and
does not necessarily mean that disease is
present.
A small amount
of tremor, known as physiological tremor,
is normal. From time to time, everyone experiences
an exaggeration of this into a more obvious
tremor, especially when tensing the muscles
concerned. Raised adrenalin levels caused
by excitement or anxiety can also result
in tremor. This is an exaggeration
of physiological tremor.
Essential-familial
tremor is an embarrassing condition that
runs in families and produces an impression
of nervousness. It does not progress to
more serious disease. Essential tremor affects
about 1 person in 250.
Causes
Many cases are due to the harmless essential-familial
condition. Persistent tremor at rest, with
four or five movements per second, may indicate
Parkinson's disease (see article on Parkinson’s
disease), even if the tremor disappears
on complete relaxation.
Severe tremor
is also a feature of other diseases, including:
- Alcohol
abuse
- Disorders
of the cerebellar part of the brain (cerebellar
ataxia)
- Mercury
poisoning
- Multiple
sclerosis (see article on Multiple sclerosis)
- Thyrotoxicosis
(see article on Hyperthroidism)
Wilson’s disease (a rare disorder in which
damaging levels of copper occur in the
body)
- Brain
inflammation (see article on Encephalitis)
Tremor caused
by brain disorder (encephalopathy) or from
liver failure or other metabolic disorders
is called asterixis.
A variety
of drugs can cause tremor. These include
amphetamines, antidepressant drugs, caffeine,
corticosteroids and lithium. A marked tremor
is a common feature of patients under drug
treatment for certain psychiatric disorders.
Treatment
Drugs known as beta-blockers can help to reduce
essential-familial tremor. Using very
small electrical signals to stimulate part
of the brain (the thalmus) has also been
used to some effect, although this is still
an experimental treatment.
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Tremor
