The dystonias are movement disorders in which sustained muscle contractions cause twisting and repetitive movements or abnormal postures. The movements, which are involuntary and sometimes painful, may affect a single muscle; a group of muscles such as those in the arms, legs, or neck; or the entire body.
About half the cases of dystonia have no connection to disease or injury and are called primary or idiopathic dystonia. Of the primary dystonias, many cases appear to be inherited. Dystonias can also be symptoms of other diseases, some of which may be hereditary. In some individuals, symptoms of a dystonia appear in childhood. For other individuals, the symptoms emerge in late adolescence or early adulthood.
Early symptoms may include:
Other possible symptoms are tremor and voice or speech difficulties.
The initial symptoms can be very mild and may be noticeable only after prolonged exertion, stress, or fatigue. Dystonias often progress through various stages. Initially, dystonic movements are intermittent and appear only during voluntary movements or stress. Later, individuals may show dystonic postures and movements while walking and ultimately even while they are relaxed. Dystonic motions may lead to permanent physical deformities by causing tendons to shorten.
No one treatment has been found to be universally effective. Instead, doctors use a variety of therapies aimed at reducing or eliminating muscle spasms and pain. They include:
Since response to drugs varies among individuals and even in the same person over time, the most effective therapy is often individualized.