Dystonia

In dystonia, prolonged muscle contractions (spasms) force the body into abnormal, sometimes painful positions or movements.

Part or all of the body may twist or turn: the eyelids, neck, mouth, tongue, arms, legs, or trunk. The movements are usually slow and repetitive. Dystonia does not affect mental function, muscle strength, vision, or hearing. Dystonia may cause few problems or greatly interfere with functioning. It is usually chronic (that is, people continue to have spasms).

Causes

Dystonia may occur because the basal ganglia are overactive. The basal ganglia, which are clusters of nerve cells deep within the brain, help coordinate muscle movements. Dystonia may occur in people with Parkinson's disease or stroke. Drugs used to treat loss of contact with reality (antipsychotic drugs) and drugs used to treat Parkinson's disease can cause dystonia. Dystonia that affects the whole body often has a genetic cause.

Types and Symptoms

Dystonia may affect most of the muscles in the body or only one or two groups of muscles. Writer's cramp is dystonia that affects only the hand muscles, causing muscle spasms in the fingers. These spasms make holding and writing with a pen or pencil difficult.

Blepharospasm is repeated spasms of the muscles around the eyes, forcing the eyelids shut. The eyes may remain shut for seconds to minutes. Usually, both eyes are affected. Blepharospasm usually begins gradually with excessive blinking. These spasms may be triggered by bright light, fatigue, or stress. 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. When blepharospasm is very severe, the eyes may be forced closed for hours, making the person effectively blind for that time. However, blepharospasm is not painful.

Spasmodic torticollis involves spasms of the neck muscles, causing the head to twist forward, backward, or sideways. The spasms may be sustained or jerky. They can be painful. The abnormal positions sometimes cause nerves in the neck to be pinched. Touching the face gently may relieve the spasm. In about one fourth of people, the spasms spread to the face, jaw, or arms. The spasms may remain stable for years or may become progressively more severe. A few people have symptom-free periods (remissions), but symptoms eventually return.

Spasmodic dysphonia involves spasms of the muscles of the vocal cords that interfere with speech. Speech may sound strained, quavery, hoarse, whispery, jerky, staccato, or garbled and be difficult to understand. Sometimes speech is impossible.

Diagnosis and Treatment

The diagnosis is based on symptoms and results of a physical examination. Examination by a specialist, such as a neurologist or speech pathologist, may be needed. No test can confirm the diagnosis.

Correcting or eliminating the cause of dystonia, if known, usually reduces its frequency and severity. For example, if a drug is causing dystonia, the drug is discontinued. The dystonia may then lessen. If dystonia persists after an antipsychotic drug is discontinued, pimozide (used to lessen involuntary movements) may help.

If the cause of dystonia is unknown, the effectiveness of treatment varies. Injecting botulinum toxin (which can paralyze muscles) into the overactive muscle is usually effective. The injections reduce the activity of the muscle enough to relieve the spasm but not enough to cause paralysis. These injections are useful when only part of the body is affected, as in blepharospasm, spasmodic torticollis, and spasmodic dysphonia. Injections are repeated every few months.

If the whole body is affected or if botulinum injections are not effective, certain drugs may be given by mouth. However, side effects of the drugs may limit the dose that can be given. Some people benefit from baclofen, a muscle relaxant. However, this drug can cause excessive drowsiness, confusion, and hallucinations. Drugs with anticholinergic effects, such as trihexyphenidyl and diphenhydramine, are sometimes helpful. However, these drugs can cause drowsiness, confusion, blurred vision, constipation, dry mouth, light-headedness, difficulty starting and continuing urination, and loss of bladder control (urinary incontinence), especially in older people. Benzodiazepines (a type of sedative, used to calm, relieve anxiety, or aid sleep) may be used. Some people improve dramatically when treated with levodopa, a drug often used to treat Parkinson's disease. The antipsychotic drugs clozapine and olanzapine may be useful.

If drugs are ineffective and symptoms are severe, surgery may be recommended. Surgery may consist of destroying a tiny area in one basal ganglion (a procedure called pallidotomy) or implanting electrodes to stimulate the same area of the brain (deep brain stimulation).

Physical therapy helps some people, especially those who are treated with botulin injections. Exercises to stretch muscles or maintain a joint's range of motion may be recommended.