What causes tremor? 18 possible conditions
A tremor is an unintentional and uncontrollable rhythmic movement of one part or one limb of your body. A tremor can occur in any part of the body and at any time. It’s usually the result of a problem in the part of your brain that controls muscular movement. Tremors are not always serious, but in some cases they may indicate a serious disorder. Most tremors can’t be treated easily, but they will often go away on their own.
It’s important to note that muscle spasms, muscle twitches, and tremors are not the same thing. A muscle spasm is the involuntary contraction of a muscle. A muscle twitch is an uncontrolled fine movement of a small portion of a larger muscle. This twitch may be visible under the skin.
Tremors are divided into two types: resting and action.
Resting tremors occur when you’re sitting or lying still. Once you begin to move around, you’ll notice that the tremor goes away. Resting tremors often affect only the hands or fingers.
Action tremors occur during movement of the affected body part. Action tremors are further divided into subcategories:
- An intention tremor occurs during targeted movement, such as touching your finger to your nose.
- A postural tremor occurs when holding a position against gravity, such as holding your arm or leg outstretched.
- Task-specific tremors occur during a specific activity, such as writing.
- Kinetic tremors occur during movement of a body part, such as moving your wrist up and down.
- Isometric tremors occur during the voluntary contraction of a muscle without other movement of the muscle.
In addition to type, tremors are also classified by their appearance and cause.
Essential tremor is the most common type of movement disorder. Essential tremors are usually postural or intention tremors. An essential tremor may be mild and not progress, or it may slowly progress. If the essential tremor progresses, it often starts on one side and then affects both sides within a few years.
Essential tremors weren’t thought to be associated with any disease processes. However, recent studies have connected them to mild degeneration in the cerebellum, which is the part of the brain that controls motor movement. Essential tremors are sometimes associated with mild walking difficulty and hearing disability, and they tend to run in families.
A Parkinsonian tremor is usually a resting tremor and is often the first sign of Parkinson’s disease. It’s caused by damage to parts of the brain that control movement. The onset is usually after age 60. It begins in one limb or on one side of the body, and then it progresses to the other side.
A dystonic tremor occurs irregularly. Complete rest can relieve these tremors. This tremor occurs in people who have dystonia, which is a movement disorder characterized by involuntary muscle contractions. The muscle contractions cause twisting and repetitive motions or abnormal postures, such as twisting of the neck. These can occur at any age.
The cerebellum is the part of the hindbrain that controls movement and balance. A cerebellar tremor is a type of intention tremor caused by lesions or damage to the cerebellum from a stroke, tumor, or disease, such as multiple sclerosis. It may also be the result of chronic alcoholism or overuse of certain medications.
A psychogenic tremor may present as any of the tremor types. It’s characterized by sudden onset and remission, changes in the direction of your tremor and the affected body part, and greatly decreased activity when you’re distracted. Patients with psychogenic tremors often have conversion disorder (a psychological condition that produces physical symptoms) or another psychiatric disease.
An orthostatic tremor usually occurs in the legs. This is a rapid, rhythmic muscle contraction that occurs immediately after you stand. This tremor is often perceived as unsteadiness. There are no other clinical signs or symptoms. The unsteadiness stops when you sit, are lifted, or when you start walking.
A physiologic tremor is often caused by a reaction to certain drugs, alcohol withdrawal, or medical conditions, such as hypoglycemia (low blood sugar) or an overactive thyroid gland. Physiologic tremor usually goes away if you eliminate the cause.
Prescription medications, diseases, injuries, stress, and caffeine can all cause tremors.
The most common causes of tremors are:
- muscle fatigue
- ingesting too much caffeine
- low blood sugar levels
Medical conditions that can cause tremors include:
- traumatic brain injury
- Parkinson’s disease, which is a degenerative disease caused by loss of dopamine-producing brain cells
- multiple sclerosis, which is a condition in which your immune system attacks your brain and spinal cord
- hyperthyroidism, which is a condition in which your body produces too much thyroid hormone
Sometimes, tremors are considered normal. When you’re under a lot of stress or experiencing anxiety or fear, tremors may occur. Once the feeling subsides, the tremor usually stops. Tremors are also often part of medical disorders that affect the brain, nervous system, or muscles.
You should see your doctor if you develop unexplained tremors.
During a physical examination, the doctor will observe the affected area. Tremors are apparent upon visual inspection. However, the cause of the tremor can’t be diagnosed until your doctor performs further tests. Your doctor may request that you write or hold an object to evaluate the severity of your tremor. Your doctor may also collect blood and urine samples to check for signs of thyroid disease or other medical conditions.
The doctor may order a neurological exam. This exam will check the functioning of your nervous system. It will measure your tendon reflexes, coordination, posture, muscle strength, muscle tone, and ability to feel touch. During the exam, you may need to touch your finger to your nose, draw a spiral, or perform other tasks or exercises.
Your doctor may also order an electromyogram, or EMG. This test measures involuntary muscle activity and muscle response to nerve stimulation.
If you get treatment for the underlying condition causing the tremor, that treatment may be enough to cure it. Treatments for tremor include:
There are some medications that are commonly used to treat the tremor itself. Your doctor may prescribe them for you.
- Beta blockers are usually used to treat people with high blood pressure or heart disease. However, they have been shown to reduce tremors in some people.
- Tranquilizers, such as alprazolam (Xanax), may relieve tremors that are triggered by anxiety.
- Anti-seizure medications are sometimes prescribed for people who cannot take beta blockers or who have tremors that are not helped by beta blockers.
Botox injections may also relieve tremors. These chemical injections are often given to people who have tremors that affect the face and head.
Physical therapy may help strengthen your muscles and improve your coordination. The use of wrist weights and adaptive devices, such as heavier utensils, may also help relieve tremors.
Brain Stimulation Surgery
Brain stimulation surgery may be the only option for those with debilitating tremors. During this operation, the surgeon inserts an electrical probe into the portion of your brain responsible for the tremors. Once the probe is in place, a wire feeds from the probe into your chest, under your skin. The surgeon places a small device in your chest and attaches the wire to it. This device sends pulses to the probe to stop the brain from producing tremors.
- Ahmed, A., & Sweeny, P. (n.d.). Tremors. Retrieved from http://www.clevelandclinicmeded.com/medicalpubs/diseasemanagement/neurology/tremors/
- Mayo Clinic Staff. (2013, February 20). Essential tremor. Retrieved from http://www.mayoclinic.com/health/essential-tremor/DS00367/METHOD=print
- Tremor fact sheet. (2015, July 6). Retrieved from http://www.ninds.nih.gov/disorders/tremor/detail_tremor.htm
See a list of possible causes in order from the most common to the least.
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