Dystonia is a movement disorder that causes involuntary contractions of your muscles. These contractions result in twisting and repetitive movements. Sometimes they are painful.
Dystonia can affect just one muscle, a group of muscles or all of your muscles. Symptoms can include tremors, voice problems or a dragging foot. Symptoms often start in childhood. They can also start in the late teens or early adulthood. Some cases worsen over time. Others are mild.
Some people inherit dystonia. Others have it because of another disease. Researchers think that dystonia may be due to a problem in the part of the brain that handles messages about muscle contractions. There is no cure. Doctors use medicines, Botox injections, surgery, physical therapy, and other treatments to reduce or eliminate muscle spasms and pain.
NIH: National Institute of Neurological Disorders and Stroke