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Tremors are rhythmic, alternating, or oscillatory movements. A tremor can be a normal exaggeration of movement, a primary disorder, or a symptom of a cerebellar disorder or Parkinson's disease. Diagnosis is usually clinical. Treatment varies by etiology.
Tremor can be categorized by the following:
Resting tremor is maximal at rest and decreases with activity; it is usually a symptom of Parkinson's disease.
Postural tremor is maximal when a limb is maintained in a fixed position against gravity; gradual onset suggests physiologic or essential tremor, and acute onset suggests a toxic or metabolic disorder.
Intention tremor is maximal during movement toward a target, as in finger-to-nose testing. It suggests a cerebellar disorder but may result from multiple sclerosis or Wilson's disease.
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Table 5
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Some Causes of Secondary
Tremor*
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Cause
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Type of Tremor
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Comments
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Alcoholism
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A permanent, generalized tremor of 3–12 Hz, depending on the body part involved
Usually, postural or action tremor of variable amplitude
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Patients have a history of excessive alcohol use.
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Alcohol withdrawal
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A coarse tremor of 7–14 Hz involving the entire body
Can be action, postural, or resting tremor
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A drink of alcohol characteristically eliminates or lessens the tremor.
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Drug use
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Depending on the drug, a tremor of 3–15 Hz and variable amplitude
Usually, action or postural tremor; rarely, resting tremor
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Caffeine, lithium , metaproterenol, terbutaline , theophylline , tricyclic antidepressants, or valproate can cause action tremor.
Antipsychotic drugs can cause resting tremor.
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Drug withdrawal (eg, opioids)
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A tremor of 4–12 Hz and low amplitude
Usually, action or postural tremor
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This tremor is uncommon among the elderly.
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Hyperthyroidism
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A fine, regular, rapid tremor
Usually confined to the hands and fingers when outstretched
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Thyroid function tests help with diagnosis.
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Toxins exposure (eg, to methyl bromide or heavy metals)
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Depending on the toxin, a tremor of 3–15 Hz and variable amplitude
Can be action, postural, or resting tremor
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Methyl bromide, mercury, or lead may cause action tremor.
Mg may cause resting tremor.
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*These tremors are treated by treating the cause.
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Physiologic
tremor:
Physiologic tremor is present normally but is usually so slight that it is noticeable only under certain conditions. It is predominantly a postural or intention tremor. The tremor is fine and rapid (8 to 13 Hz). It is most visible when the hands are outstretched. Amplitude may be increased (enhanced) by the following:
Alcohol and other sedatives usually suppress the tremor.
No treatment is necessary unless symptoms are bothersome. Physiologic tremor enhanced by alcohol withdrawal or thyrotoxicosis responds to treatment of the underlying condition. Oral benzodiazepines tid or qid (eg, diazepam 2 to 10 mg, lorazepam 1 to 2 mg, oxazepam 10 to 30 mg) may be useful for people with tremor and chronic anxiety, but continuous use should be avoided. Propranolol 20 to 80 mg po qid or another β-blocker (eg, nadolol , 20 to 80 mg po once/day) is often effective for tremor enhanced by drugs or acute anxiety (eg, stage fright). Primidone 50 to 250 mg po tid may be tried if β-blockers are ineffective or poorly tolerated. For some patients, a small amount of alcohol is effective.
Essential
tremor (benign hereditary tremor, senile tremor):
The tremor is coarse or fine, of medium frequency (4 to 8 Hz), and usually bilateral; it can affect the hands, head, and voice. It tends to increase with aging and thus may be incorrectly called senile tremor. In 50% of patients, inheritance is autosomal dominant. The tremor is minimal or absent at rest. It may be enhanced by any factor that enhances physiologic tremor, but such factors are not required. It can sometimes be differentiated from physiologic tremor, but the difference is not always obvious. Some experts consider essential tremor a variant of physiologic tremor; drug treatment is the same.
Occupational therapists can help patients modify their lifestyle to deal with symptoms (eg, avoiding eating soup in public, holding objects close to the body to avoid dropping them, using assistive devices). If drug treatment is ineffective and tremor is debilitating, deep brain stimulation of the ventralis intermediate nucleus of the thalamus (which requires surgery) is effective.
Tremor
of cerebellar disease:
This tremor is an intention tremor. No effective drug is available; physical measures (eg, weighting the affected limbs or teaching patients to brace the proximal limb during activity) sometimes help.
Asterixis:
Asterixis is not a tremor. In asterixis, muscle tone lapses when wrist extension is attempted, resulting in repetitive, nonrhythmic, nonoscillatory wrist flexion. Asterixis, a sign of chronic renal or liver failure, must be differentiated from tremor.
Last full review/revision August 2007 by David Eidelberg, MD; Michael Pourfar, MD
Content last modified August 2007
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