Table: Some Causes and Features of Tremor - Merck Manuals Consumer Version

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Some Causes and Features of Tremor

Some Causes and Features of Tremor

Cause	Features*	Tests
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 Amitriptyline (an antidepressant) Beta-adrenergic drugs (used to treat asthma) Cocaine Haloperidol (used to treat schizophrenia) Lithium (used to treat bipolar disorder) SSRIs (a type of antidepressant) Tamoxifen (used to treat breast cancer) Valproate (an antiseizure drug)	History of drug use	Stopping the drug to see whether the tremor goes away
Hormonal, metabolic, and toxic abnormalities that affect the brain: Brain damage due to lack of oxygen (anoxic encephalopathy) Liver failure (causing brain dysfunction called hepatic encephalopathy) An overactive thyroid gland (hyperthyroidism) Kidney failure (causing brain dysfunction called uremic encephalopathy Overactive parathyroid glands (hyperparathyroidism) Low blood sugar (hypoglycemia) Poisons, including heavy metals such as lead	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
Parkinsonism triggered by a drug, such as certain antipsychotic drugs and drugs used to relieve nausea	A history of drug use	Stopping the drug to see whether the tremor goes away
Parkinson disease	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
Progressive supranuclear palsy	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
Cerebellar disorders: Chronic alcoholism Friedreich ataxia Hemorrhage Head injury Multiple sclerosis Spinocerebellar ataxias Stroke Tumor	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
Disorders that affect many of the nerves outside the brain and spinal cord (polyneuropathies): Guillain-Barré syndrome Diabetes	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.
MRI = magnetic resonance imaging; SSRIs = selective serotonin reuptake inhibitors (a type of antidepressant).