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Merck Manual

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Quick Facts



The Manual's Editorial Staff

Last full review/revision Jul 2020| Content last modified Jul 2020
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What is dystonia?

"Dys" means bad or not normal. "Tonia" refers to muscle tension or tone. So dystonia is abnormal muscle tone. Your muscles tighten up without you wanting them to.

The abnormal muscle tone of dystonia usually results in muscle cramping. A cramp is a sudden painful muscle contraction (spasm) that you can't control. Muscle cramps may happen more and more over time and force your body into an odd or twisted position.

  • At first, muscle spasms come and go, so you may blink your eyes, grind your jaw, move your arms, or make other motions

  • Later, the affected muscles may stay in spasm so part of your body is stuck in one position

  • Dystonia happens when there's overactivity in the parts of your brain that control your muscles

  • Dystonia can be inherited or caused by brain disorders or by some medicines

  • Doctors will treat the cause of your dystonia and may prescribe pills or injections to help relax your muscles

What causes dystonia?

Dystonia is caused by:

  • Overactivity in the parts of your brain that control your muscles

This overactivity can happen because of:

What are the symptoms of dystonia?

The main symptom is:

  • A long-lasting muscle cramp

At first the muscle cramp happens only once in a while or during stress. Over time, the muscle cramp happens more often and lasts longer. The cramping body part may stay in a specific, sometimes painful, position. This can cause disability.

Dystonia can happen in your:

  • Eyelid, usually starting as extra blinking, eye discomfort, or extreme sensitivity to bright light

  • Neck muscles, causing a twisted, painful neck ("wry neck")

  • Vocal cords, causing changes in your ability to speak or the quality of your voice

  • Face muscles, which may include uncontrolled blinking, jaw grinding, and odd facial expressions

  • Any muscle you overuse—for example, the fingers of a professional pianist

How can doctors tell if I have dystonia?

Doctors diagnose dystonia based on your symptoms and a physical exam. There are no tests for dystonia, but doctors may look to see if you have a brain disorder by doing:

How do doctors treat dystonia?

Doctors will treat the cause of your dystonia if they can. Other treatments include:

  • Medicines, including nerve-blocking medicines and mild sedatives (medicine to relax your body and help you sleep)

  • Botulinum toxin shots (Botox®) into the stiff muscle, which will relax it

  • Sometimes deep brain stimulation (small electrodes placed in your brain to ease repeated muscle cramps)

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