Dystonia is a neurological disorder that results in involuntary sustained muscle contractions that force muscles into unnatural positions through twisting and repetitive movements. It is caused by any of a number of causes; heredity, physical trauma, infections, poisoning, or pharmaceutical reactions.
Because of the numerous possible causes treatment is highly individualized and can include oral medications, botulinum neurotoxin injections, physical therapy, supportive therapies, or surgery to create deep brain stimulation. Although dystonia can occur on its own it can also be comorbid (occur at the same time) with other disorders such as Parkinson's disease, multiple sclerosis, and cerebral palsy. Dystonias can also be task-specific and caused by occupational or recreational movements and overuse of certain body parts.
For example, involuntary muscle spasms in the wrists, hands, and arms occur in golfers and musicians because they use (and sometimes overuse) those specific muscles frequently. Chronic writer’s cramp is a type of dystonia.