Merck Manual

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Some Causes and Features of Tremor

Some Causes and Features of Tremor



Diagnostic Approach†

Postural tremor (tremor when a limb is held outstretched)

Alcohol or a sedative (such as a benzodiazepine) when use is stopped

Agitation and a fine tremor starting 24–72 hours after the last use of alcohol or a benzodiazepine

Sometimes high blood pressure, a rapid heart rate, or fever, especially in people who are hospitalized

A doctor's examination

Drugs, such as

History of drug use

Stopping the drug to see whether the tremor goes away

Hormonal, metabolic, and toxic abnormalities that affect the brain:

A tremor plus one or more of the following:

  • Coma or lethargy (suggesting brain dysfunction)

  • Quick, lightning-like muscle contractions (called myoclonus)

  • Symptoms of an underlying disorder, such as hyperthyroidism

For hyperthyroidism: Difficulty tolerating heat, excessive sweating, an increased appetite, weight loss, bulging eyes, and frequent bowel movements

Tests to help identify the cause, such as blood tests

  • To evaluate how well the liver, thyroid gland, kidneys, and parathyroid glands are functioning

  • To measure blood sugar

  • To check for poisons

Essential tremor

A coarse or fine, slow tremor that

  • Worsens slowly, over many years

  • Usually affects both arms and sometimes the head and voice

  • Often occurs in people with a family history of tremor

No other symptoms of nervous system malfunction

A doctor's examination

Physiologic tremor

A fine, rapid tremor that

  • Occurs in otherwise healthy people

  • May become more noticeable when people take or stop taking certain drugs or feel stressed or anxious

  • Usually lessens when people drink small amounts of alcohol or take low doses of sedatives

A doctor's examination

Resting tremor

A history of drug use

Stopping the drug to see whether the tremor goes away

A slow alternating tremor that

  • Often involves moving the thumb against the index finger as if rolling moving small objects around (called pill rolling)

  • Sometimes also affects the chin or a leg

  • Usually starts on one side

  • Is accompanied by other symptoms, such as muscle stiffness, shaky and tiny handwriting, slow movements, and a shuffling walk

Often no family history of tremor and no lessening of tremor after drinking alcohol

A doctor's examination

Use of the drug levodopa to see whether improvement occurs

A sometimes coarse or jerky tremor that is often inconspicuous

In older people who have difficulty looking down and eventually looking up, muscle stiffness, difficulty moving, early falls, and dementia

A doctor's examination

Intention tremor

A slow tremor that

  • Usually occurs on one side of the body

  • Is accompanied by lack of coordination (ataxia), especially when attempting to touch or grasp a targeted object or perform rapid alternating movements

  • Affects the muscles used in speech, making the voice tremble

In some people, a family history of the disorder (as for Friedreich ataxia or spinocerebellar ataxias)

MRI of the brain

Drugs, such as

  • Alcohol

  • Antiseizure drugs (such as phenytoin and valproate)

  • Beta-agonists

  • Cyclosporine

  • Lithium

  • Tacrolimus

A history of drug use

Stopping the drug to see whether the tremor goes away

Complex tremors

A tremor that

  • Varies in speed and width

  • Often occurs when people reach for an object and worsens as they get closer to the object

  • Often worsens when people hold a limb outstretched

  • Is accompanied by other symptoms of nerve damage, such as weakness, a pins-and-needles sensation, and loss of sensation

Electromyography (stimulating muscles and recording their electrical activity)

Other tests to identify the cause

Psychogenic tremor (due to psychologic factors)

A tremor that

  • Begins suddenly or may stop just as suddenly

  • Varies in speed and width

  • Lessens when people are distracted

A doctor's examination

* Features include symptoms and results of the doctor's examination. Features mentioned are typical but not always present.

† Although a doctor's examination is always done, it is mentioned in this column only if the diagnosis can sometimes be made by the doctor's examination alone, without any testing

MRI = magnetic resonance imaging; SSRIs = selective serotonin reuptake inhibitors (a type of antidepressant).