Definition
Acute dystonia is a movement disorder in which there is a state of abnormal involuntary muscle contraction, resulting in typically slow, sustained and repetitive movements, cramping or abnormal posturing.
These contractions are painful. They often provoke anxiety.
Although dystonias may occur in any muscle group, they most commonly affect muscles in the head and neck.
Usually only one muscle group is affected, though in approximately 20% of cases the phenomenon may affect more than one muscle group.