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

Some Causes and Features of Tremor

Cause	Features*	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 Amitriptyline (an antidepressant) Beta-adrenergic drugs Beta-Adrenergic Drugs Drugs allow most people with asthma to lead relatively normal lives. Most of the drugs used to treat an asthma attack can be used (often in lower doses) to prevent attacks. (See also Asthma... read more (used to treat asthma) Cocaine Cocaine Cocaine is an addictive stimulant drug made from leaves of the coca plant. Cocaine is a strong stimulant that increases alertness, causes euphoria, and makes people feel powerful. High doses... read more Haloperidol (used to treat schizophrenia) Lithium Lithium In bipolar disorder (formerly called manic-depressive illness), episodes of depression alternate with episodes of mania or a less severe form of mania called hypomania. Mania is characterized... read more (used to treat bipolar disorder) SSRIs Selective serotonin reuptake inhibitors (SSRIs) Agomelatine, a new type of antidepressant, is a possible treatment for major depressive episodes. Several types of drugs can be used to treat depression: Selective serotonin reuptake inhibitors... read more (a type of antidepressant) Tamoxifen Hormone-blocking drugs (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 Liver Failure Liver failure is severe deterioration in liver function. Liver failure is caused by a disorder or substance that damages the liver. Most people have jaundice (yellow skin and eyes), feel tired... read more (causing brain dysfunction called hepatic encephalopathy Hepatic Encephalopathy Hepatic encephalopathy is deterioration of brain function that occurs in people with severe liver disease because toxic substances normally removed by the liver build up in the blood and reach... read more ) An overactive thyroid gland ( hyperthyroidism Hyperthyroidism Hyperthyroidism is overactivity of the thyroid gland that leads to high levels of thyroid hormones and speeding up of vital body functions. Graves disease is the most common cause of hyperthyroidism... read more ) Kidney failure Overview of Kidney Failure This chapter includes a new section on COVID-19 and acute kidney injury (AKI). Kidney failure is the inability of the kidneys to adequately filter metabolic waste products from the blood. Kidney... read more (causing brain dysfunction called uremic encephalopathy Overactive parathyroid glands ( hyperparathyroidism Hyperparathyroidism In hypercalcemia, the level of calcium in blood is too high. A high calcium level may result from a problem with the parathyroid glands, as well as from diet, cancer, or disorders affecting... read more ) Low blood sugar ( hypoglycemia Hypoglycemia Hypoglycemia is abnormally low levels of sugar (glucose) in the blood. Hypoglycemia is most often caused by medications taken to control diabetes. Much less common causes of hypoglycemia include... read more ) 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 Parkinsonism Parkinsonism refers to symptoms of Parkinson disease (such as slow movements and tremors) that are caused by another condition. Parkinsonism is caused by brain disorders, brain injuries, or... read more 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 Parkinson Disease (PD) Parkinson disease is a slowly progressive degenerative disorder of specific areas of the brain. It is characterized by tremor when muscles are at rest (resting tremor), increased muscle tone... read more	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 Progressive Supranuclear Palsy (PSP) Progressive supranuclear palsy is characterized by slow movements, muscle stiffness (rigidity), problems moving the eyes, and a tendency to fall backward. Progressive supranuclear palsy progresses... read more	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 Coordination Disorders Coordination disorders often result from malfunction of the cerebellum, the part of the brain that coordinates voluntary movements and controls balance. The cerebellum malfunctions, causing... read more : Chronic alcoholism Alcohol Use Alcohol (ethanol) is a depressant (it slows down brain and nervous system functioning). Consuming large amounts rapidly or regularly can cause health problems, including organ damage, coma,... read more Friedreich ataxia Hemorrhage Head injury Overview of Head Injuries Head injuries that involve the brain are particularly concerning. Common causes of head injuries include falls, motor vehicle crashes, assaults, and mishaps during sports and recreational activities... read more Multiple sclerosis Multiple Sclerosis (MS) In multiple sclerosis, patches of myelin (the substance that covers most nerve fibers) and underlying nerve fibers in the brain, optic nerves, and spinal cord are damaged or destroyed. The cause... read more Spinocerebellar ataxias Stroke Overview of Stroke A stroke occurs when an artery to the brain becomes blocked or ruptures, resulting in death of an area of brain tissue due to loss of its blood supply (cerebral infarction) and symptoms that... read more Tumor Overview of Brain Tumors A brain tumor can be a noncancerous (benign) or cancerous (malignant) growth in the brain. It may originate in the brain or have spread (metastasized) to the brain from another part of the body... read more	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 Polyneuropathy Polyneuropathy is the simultaneous malfunction of many peripheral nerves throughout the body. Infections, toxins, drugs, cancers, nutritional deficiencies, diabetes, autoimmune disorders, and... read more ): Guillain-Barré syndrome Guillain-Barré Syndrome (GBS) Guillain-Barré syndrome is a form of polyneuropathy causing muscle weakness, which usually worsens over a few days to weeks, then slowly improves or returns to normal on its own. With treatment... read more Diabetes Diabetes Mellitus (DM) Diabetes mellitus is a disorder in which the body does not produce enough or respond normally to insulin, causing blood sugar (glucose) levels to be abnormally high. Urination and thirst are... read more	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).