Introduction to Dystonia

Doctor examines man's hand and wrist
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Normal movements depend on the coordinated contraction of one muscle with the relaxation of another. For example, your biceps flexes your arm and your triceps extends it. If both your triceps and biceps contract at the same time, the arm tenses but doesn't move. In fact, if the muscles contract simultaneously and unintentionally, the body part can be twisted into abnormal postures. This is what happens in dystonia.

Dystonia can affect any part of the body, including the arms, legs, trunk, neck, eyelids or face. One of the most familiar forms of dystonia is writer's cramp, which affects the hand when writing. This is an example of task-specific dystonia, but dystonia can also happen at any time. It may be intermittent, sustained, rhythmic, or tremulous. Like many neurological problems, dystonia is worsened by stress or fatigue.

To help treat dystonia, it helps to categorize the problem. There are several ways to classify dystonia, including the age of onset, bodily distribution, cause of dystonia, and genetics.

Age of Onset

When someone under the age of 26 years suffers from dystonia, this is considered to be early onset. While we don't know why, early dystonia tends to start more in the legs than the arms. Frequently, the cause is genetic.

Over the age of 26, dystonia is more common in the neck and arms than the legs.

Rather than being primarily genetic in cause, dystonia in older people tends to be more associated with or caused by other factors, although dystonia of unknown causes is still frequent.

For example, one of the most common causes of dystonia is as a reaction to a medication like Reglan, which is used to treat gastrointestinal problems.

Several other disorders of the central nervous system become more common as we get older, and can lead to dystonia as well. Examples include Parkinson's disease, traumatic brain injury, or stroke.

Bodily Distribution

Dystonia can also be classified by bodily distribution. Perhaps the most common is focal dystonia, meaning that only one body part is affected, as in writer's cramp.

Neurologists have special names for some common kinds of focal dystonia. For example, a twisting dystonia of the neck is called torticollis, and dystonia of the eyelids is called blepharospasm.

In segmental dystonia, two body regions connected to each other are affected, and in multifocal dystonia, two unrelated body regions are dystonic.

In hemidystonia, half the body is affected. Finally, in generalized dystonia, both legs and at least one additional body part is dystonic. This can represent a severe genetic disorder, or if it happens all at once, it may be the result of a drug reaction.

Causes of Dystonia

In primary dystonia, there is no known underlying injury or disease.

The dystonia may be due to a genetic mutation, as in DYT1 idiopathic torsion dystonia, or it may be due to other unknown causes.

There are dozens of inherited forms of dystonia. The most common is DYT1, which begins in the arm and leg around the age of 13 years. Sixty-seven percent of the time, it progresses to a multifocal or generalized dystonia. Other forms of genetic dystonia are less common, including Lubag's syndrome, Segawa syndrome and more. Each type of dystonia has distinctive characteristics. For example, Lubag syndrome affects men predominantly. The dystonia of Segawa syndrome has symptoms that worsen at night, and responds well to the levodopa medication more commonly used to treat Parkinson's disease.

In secondary dystonia, the dystonia is caused by some kind of damage to the nervous system, such as stroke injury, or a medication side effect. Neurodegenerative diseases, like Parkinson's disease, Wilson's disease, Huntington's disease, and some mitochondrial disorders can also lead to dystonia.

Sometimes, no cause of the dystonia is found. This does not mean that the dystonia can't be treated, though. Physical therapy, oral and injected medications, and even surgical options like deep brain stimulation can be useful. In many cases of dystonia caused by a drug side effect, a simple Benadryl can solve the problem. With so many options for treatment available, it is important that people with dystonia see a medical professional to get the help they need.


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