Dystonia is characterized by involuntary sustained muscle contractions that may make people freeze in the middle of an action or make the entire body, the trunk, or another part of the body twist or turn.

• Dystonia may result from a genetic mutation, a disorder, or a drug.
• Spasms occur in the affected part of the body , distorting the position of that body part.
• The cause is corrected if possible, but drugs, such as mild sedatives, levodopa plus carbidopa, and botulinum toxin, may help.

Causes

Dystonia seems to result from overactivity in several areas of the brain—the basal ganglia, thalamus, cerebellum, and cerebral cortex. Dystonia may result from a genetic mutation (called primary dystonia) or from a disorder or drug (called secondary dystonia). Antipsychotic drugs can cause various types of dystonia, including shutting of the eyelids, twisting of the neck (spasmodic torticollis) or back, grimacing, puckering of the lips, protrusion of the tongue, and writhing of the arms or legs.

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Causes of Dystonias Type Examples Disorders Cerebral palsy Genetic disorders, such as generalized dystonia and dopa-responsive dystonia Multiple sclerosis A severe lack of oxygen to the brain (which may occur at birth or later in life) Stroke Toxicity due to accumulation of certain metals (such as copper in Wilson's disease) Drugs Antiemetics (such as metoclopramide and prochlorperazine) Antipsychotic drugs (such as chlorpromazine, fluphenazine, haloperidol, and thiothixene)

Types and Symptoms

Dystonias may affect one part (focal dystonias) or several parts (segmental dystonias) of the body. Sometimes they affect the whole body (generalized dystonias).

Focal and Segmental Dystonias: Dystonias that affect one or several body parts typically start in a person's 30s or 40s and affect women more often. Initially, spasms may occur randomly or only during stress. Certain movements of the affected body part may trigger the spasms, which may disappear during rest. Over days, weeks, or many years, spasms may become more frequent and may continue during rest. Eventually, the affected body part remains distorted, sometimes in a painful position. Severe disability results. The following are examples of focal and segmental dystonias:

• Blepharospasm: This dystonia affects mainly the eyelids. The eyelids are repeatedly and involuntarily forced shut. Occasionally, only one eye is affected at first, but ultimately, the other eye is also affected. It usually begins as excessive blinking, eye irritation, or extreme sensitivity to bright light. Many people with blepharospasm find ways to keep their eyes open, such as yawning, singing, or opening the mouth wide. These techniques become less effective as the disorder progresses. Blepharospasm can severely impair vision.
• Spasmodic torticollis: Torticollis specifically affects the muscles of the neck. It is one of the most common focal dystonias in adults. The cause is often unknown but, in some cases, is probably genetic. Torticollis can also be caused by drugs that block dopamine, such as haloperidol. Rarely, torticollis is present at birth (called congenital torticollis). In adults, it often begins with a pulling sensation of the neck. The head, neck, and shoulders can twist into a distorted position that persists. Early in the disorder the spasm can sometimes be suppressed with effort. Or people sometimes discover tricks that make the spasm stop temporarily. For example, they may touch their face in a particular spot (usually on the side opposite the twisting).
• Spasmodic dysphonia: The muscles of the vocal cords, which control speech, contract involuntarily. Speech may be impossible or may sound strained, quavery, hoarse, whispery, jerky, creaky, staccato, or garbled and be difficult to understand.
• Occupational dystonias: These dystonias, also called task-specific dystonias, affect one part of the body and often result from overuse. For example, golfers may have involuntary muscle spasms in the hands and wrists (called the yips). The yips may make putting nearly impossible. What is supposed to be a 3-foot putt can become a 15-foot putt when a golfer loses control because of the yips. Similarly, musicians, especially concert pianists, may have bizarre spasms of the fingers, hands, or arms that prevent them from performing. Musicians who play wind instruments may have spasms of the mouth. Persistent writer's cramp may be dystonia.
• Meige's disease: This dystonia combines involuntary blinking with jaw grinding and grimacing. Thus, it is also called blepharospasm-oromandibular dystonia. (“Blepharo” refers to the eyelids, “oro” refers to the mouth, and “mandibular” refers to the jaw.) It usually begins in late middle age.

Generalized Dystonias: Dystonias that affect the whole body include the following:

Did You Know... Drugs used to treat nausea or psychosis sometimes cause abnormal sustained muscle contractions (dystonias). Botulinum toxin, also used to treat facial wrinkles, is used to treat some dystonias.

• Generalized dystonia: This rare dystonia, also called idiopathic torsion dystonia, is progressive and often hereditary. In many cases, specific genetic mutations have been identified. The gene most commonly affected is the DYT1 gene. The resulting dystonia is called DYT1 dystonia. Involuntary movements result in sustained, often bizarre postures. Typically, symptoms begin during childhood, often with turning the foot in during walking. The dystonia may affect only the trunk or a leg but sometimes affects the whole body, ultimately confining children to a wheelchair. When this dystonia develops in adults, it usually begins in the face or arms and usually does not affect other parts of the body. Mental function is not affected.
• Dopa-responsive dystonia: This rare form of dystonia is hereditary. Symptoms usually begin during childhood. Typically, one leg is affected first. As a result, children tend to walk on tiptoes. Symptoms worsen at night. Walking becomes progressively more difficult, and both arms and legs are affected. However, some children have only mild symptoms, such as muscle cramps after exercise. Sometimes symptoms appear later in life and resemble those of Parkinson's disease. Movements may be slow, balance may be difficult to maintain, and a tremor may occur in the hands during rest. Symptoms lessen dramatically when people are given low doses of levodopa. If levodopa relieves the symptoms, the diagnosis is confirmed.

Treatment

Correcting or eliminating the cause of dystonia, if known, usually reduces the spasms. For example, drugs used to treat multiple sclerosis may reduce spasms related to that disease. When dystonia is due to use of an antipsychotic drug, promptly taking diphenhydramine by injection or by mouth usually stops the spasms quickly, and the antipsychotic is stopped.

For generalized dystonia, a drug with anticholinergic effects (such as trihexyphenidyl or benztropine) is most commonly used. These drugs reduce spasms by blocking specific nerve impulses involved in causing the spasms. However, anticholinergic effects also include confusion, drowsiness, dry mouth, blurred vision, dizziness, constipation, difficulty urinating, loss of bladder control, and tremor, which are troublesome, especially in older people. A benzodiazepine (a mild sedative) such as clonazepam, baclofen (a muscle relaxant), or both are also usually given. Baclofen may be given by mouth or by a pump implanted in the spinal canal. If generalized dystonia is severe or does not respond to drugs, tiny electrodes may be surgically implanted in the basal ganglia (a procedure called deep brain stimulation).

Some people, especially children with dopa-responsive dystonia, improve dramatically when they are treated with levodopa plus carbidopa.

If one or a few body parts are affected, botulinum toxin (a bacterial toxin used to paralyze muscles or to treat wrinkles) is injected into the overactive muscles. Botulinum weakens the muscle contraction but does not affect the nerves. These injections are particularly useful for blepharospasm and spasmodic torticollis.

Physical therapy helps some people, especially those who are treated with botulinum.

Last full review/revision August 2007 by David Eidelberg, MD; Michael Pourfar, MD