[Dystonia]

Dystonia, a hyperkinetic movement disorder, is characterized by involuntary muscle spasms leading to abnormal postures. Dystonic syndromes are classified by etiology (primary vs. secondary), age of onset (early vs. late onset) or spread of symptoms (focal, segmental, generalized). Clinically, young-onset dystonia is rare, often inherited and tends to spread to become generalized. In contrast, adult-onset dystonia is frequent, typically sporadic and remains focal. In recent years, 15 genes associated with dystonia have been identified and classified as DYT loci. Of these, DYT1 is the most frequent, causing early-onset generalized dystonia. Pathophysiology remains ill understood but basal ganglia dysfunction is thought to play an important role. Treatment remains symptom-oriented. A trial of levodopa is recommended in young-onset cases. In focal forms, botulinum toxin injections are helpful. Anticholinergics may be beneficial. In severe cases deep brain stimulation may be considered.