Tremors are a type of involuntary shaking movement. Involuntary means you shake without trying to do so.

See also:

• Drug-induced tremor
• Essential tremor
• Familial tremor
• Hand tremor

Tremors are caused by problems with the nerves supplying certain muscles. They may affect the whole body or just certain areas, as with hand tremor.

Types of tremors include:

• Drug-induced tremor (tremors caused by certain drugs)
• Essential tremor (no known cause)
• Familial tremor (runs in families)

Other causes of tremors may include:

• Alcohol withdrawal
• Cigarette smoking
• Hyperthyroidism
• Parkinson's disease
• Pheochromocytoma
• Too much caffeine
• Use of certain medications
• Wilson's disease

All people have some tremor when they move their hands. Stress, fatigue, anger, fear, caffeine, and cigarettes may temporarily worsen this type of tremor.

Tremors may affect the hands, arms, head, eyelids, voice box, or other muscles. They rarely affect the legs or feet.

The shaking usually involves small, rapid movements -- more than 5 times a second.

The tremors may:

• Occur when you move (action-related tremor), and may be less noticeable with rest
• Come and go, but generally get worse as you age
• Disappear with sleep
• Get worse with stress, caffeine, and certain medications
• Not affect both sides of the body the same way

Head nodding may be a symptom of a tremor.

If the tremor affects the voice box, you may have a shaking or quivering sound to your voice.

Your doctor can make the diagnosis by performing a physical exam and asking questions about your medical and personal history.

A physical exam will show shaking with movement. There are usually no other problems with coordination or changes in thinking or brain function.

The quality of the tremor is often the most helpful thing in determining the cause. What parts of the body are affected? Does it happen at rest, when moving or both? How fast, and how obvious is it?

Further tests may be needed to rule out other reasons for the tremors. Blood tests and imaging studies (such as a CT scan of the head, brain MRI, and x-rays) are usually normal.

Treament may not be necessary unless the tremors interfere with your daily activities or cause embarrassment.

Treatment depends on the cause. Tremors caused by an medical condition such as hyperthyroidism will likely get better when the condition is treated.

If the tremors are caused by certain medicine, stopping the drug usually helps them go away. Never stop taking any medicine without first talking to your doctor. See: Drug-induced tremor

Medicines may help relieve symptoms. How well medicines work depend on the individual patient.

Two medications used to treat tremors include:

• Propranolol, a drug that blocks the action of stimulating substances called neurotransmitters, particularly those related to adrenaline
• Primidone, an antiseizure drug that also controls the function of some neurotransmitters

The drugs can have significant side effects.

Side effects of propranolol include:

• Fatigue
• Nose stuffiness
• Shortness of breath (people with asthma should not use this drug)
• Slow heart beat

Side effects of primidone include:

• Drowsiness
• Difficulty concentrating
• Nausea
• Problems with walking, balance, and coordination

Other medications that may reduce tremors include:

• Antiseizure drugs such as gabapentin and topiramate
• Mild tranquilizers such as alprazolam or clonazepam
• Blood pressure drugs called calcium-channel blockers such as flunarizine and nimodipine.

Botox injections, given in the hand, have been used to reduce tremors by weakening local muscles.

In severe cases, surgery to implant a stimulating device in the brain may be an option.

Severe tremors can interfere with daily activities, especially fine motor skills (such as writing). If the tremor affects the voice box, speech problems can occur.

See your health care provider if you have a persistent, unexplained tremors or if tremors are interfering with your ability to perform daily activities.

Stress and caffeine can make tremors worse. Avoid caffeinated drinks such as coffee, tea, and soda, and other stimulants. Exercise and counseling to reduce emotional stress may also help.

Alcoholic beverages in small quantities may decrease tremors but can lead to alcohol dependence and alcohol abuse, especially if you have a family history of such problems. How alcohol helps relieve tremors is unknown.

Jankovic J. Movement disorders. In: Goetz CG, ed. Textbook of Clinical Neurology. 3rd ed. Philadelphia, PA: WB Saunders; 2007:chap. 34.