Generalized torsion dystonia


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. Those with dystonia usually have normal intelligence and no associated psychiatric disorders.


Dystonia can affect many different parts of the body. Early symptoms may include a deterioration in handwriting after writing several lines, foot cramps, and/or a tendency of one foot to pull up or drag; this may occur "out of the blue" or may occur after running or walking some distance. The neck may turn or pull involuntarily, especially when the patient is tired or stressed. Sometimes both eyes will blink rapidly and uncontrollably, rendering a person functionally blind. Other possible symptoms are tremor and voice or speech difficulties


Most—but not all—people with early onset generalized dystonia have a specific genetic mutation. The gene responsible for early-onset generalized dystonia, termed DYT1, was discovered in 1997. Early onset generalized dystonia of this kind may be referred to as DYT1 dystonia or Oppenheim’s dystonia. (Generalized forms of dystonia that occur in childhood with no mutation in the DYT1 gene may simply be called non-DYT1 early onset generalized dystonia.)


The diagnosis of early onset generalized dystonia is not made by one definitive test, but rather primarily by information from the individual and the physical and neurological examination. In most cases, assorted laboratory tests are normal and used to rule out other disorders.


Oral medications are often the mainstay of treatment for early onset generalized dystonia, both DYT1 and non-DYT1 forms. Although there is no single drug that helps an overwhelming number of individuals, there are many that may be of benefit. These oral medications include levodopa, trihexyphenidyl, benztropine, diazepam, lorazepam, clonazepam, baclofen (oral and intrathecal—especially for dystonia and spasticity), carbamazepine, tetrabenazine (with lithium), and triple therapy such as a “cocktail” that includes tetrabenazine, fluphenazine, and trihexyphenidyl.