A tremor is a rhythmic, involuntary muscle contraction. A part of the body moves back and forth. Tremor without a known cause is called essential tremor.
Tremors can be put into five categories: resting, postural, kinetic, task-specific, and psychogenic. Resting tremor occurs when a muscle is at rest, for example, when hands are lying in the lap. People with Parkinson’s disease have this type. Postural tremor occurs when people try to hold a position, such as holding the hands out. These tremors include physiological, essential, posttraumatic, and alcoholic tremors. Kinetic tremor occurs during movement with purpose, for example, during finger-to-nose testing. Task-specific tremor appears when doing tasks such as handwriting, speaking, or standing. Psychogenic tremor occurs in older and younger people and can be lessened or can disappear when people get distracted.
Essential tremors affect men and women equally, usually after age 40. These tremors can cause disability and social embarrassment.
Although the cause is unknown, abnormal communications between certain parts of the brain are thought to lead to tremors. They’re not contagious but may run in families, with parents having a 50% chance of passing them to children.
Essential tremor can affect hands, head, facial structures, vocal cords, trunk, and legs. Most occur in the hands and arms. Tremors usually affect both sides of the body, but may be more noticeable on one side. Tremors are worse when limbs are held out or in uncomfortable positions. They usually stop at rest.
The health care provider makes a diagnosis from a detailed history and physical examination. Other causes (e.g., neurological disorders, thyroid conditions, caffeine use, and medicines) must be ruled out. No specific blood tests, genetic testing, or x-ray studies can diagnose essential tremors. However, the health care provider might order blood and urine tests, computed tomography (CT), or magnetic resonance imaging (MRI) to find other possible causes of the tremors.
Mild tremors may not be treated as long as they don’t affect the ability to function. More severe tremors may first be treated with medicines called beta-blockers. such as propranolol, the one most often used.
Primidone, gabapentin, clonazepam, diazepam, and alprazolam may also be tried.
If medicines don’t work, botulinum toxin injections and surgical options may help for tremor localized to one area of the body.
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