People with dystonia may also become depressed and find great difficulty adapting their activities and livelihood to a progressing disability. Side-effects from treatment and medications can also present challenges in normal activities.In some cases, symptoms may progress and then plateau for years, or stop progressing entirely. The progression may be delayed by treatment or adaptive lifestyle changes, while forced continued use may make symptoms progress more rapidly. In others, the symptoms may progress to total disability, making some of the more risky forms of treatment worth considering. In some cases with patients who already have dystonia, a subsequent traumatic injury or the effects of general anesthesia during an unrelated surgery can cause the symptoms to progress rapidly.An accurate diagnosis may be difficult because of the way the disorder manifests itself. Affected individuals may be diagnosed as having similar and perhaps related disorders including Parkinsons disease, essential tremor, carpal tunnel syndrome, temporomandibular joint disorder, Tourettes syndrome, conversion disorder or other neuromuscular movement disorders. It has been found that the prevalence of dystonia is high in individuals with Huntingtons disease, where the most common clinical presentations are internal shoulder rotation, sustained fist clenching, knee flexion, and foot inversion. Risk factors for increased dystonia in patients with Huntingtons disease include long disease duration and use of antidopaminergic medication. Causes
Primary dystonia is suspected when the dystonia is the only sign and there is no identifiable cause or structural abnormality in the central nervous system.
Researchers suspect it is caused by a pathology of the central nervous system, likely originating in those parts of the brain concerned with motor function—such as the basal ganglia and the GABA (gamma-aminobutyric acid) producing Purkinje neurons. The precise cause of primary dystonia is unknown. In many cases it may involve some genetic predisposition towards the disorder combined with environmental conditions.Secondary dystonia refers to dystonia brought on by some identified cause, such as head injury, drug side effect (e.g. tardive dystonia), or neurological disease (e.g. Wilsons disease, stroke).Meningitis and encephalitis caused by viral, bacterial, and fungal infections of the brain have been associated with dystonia. The main mechanism is inflammation of the blood vessels, causing restriction of blood flow to the basal ganglia. Other mechanisms include direct nerve injury by the organism or a toxin, or autoimmune mechanisms.Environmental and task-related factors are suspected to trigger the development of focal dystonias because they appear disproportionately in individuals who perform high precision hand movements such as musicians, engineers, architects, and artists. Chlorpromazine can also cause dystonia, which can be often misjudged as a seizure.Neuroleptic drugs often cause dystonia, including oculogyric crisis.Malfunction of the sodium-potassium pump may be a factor in some dystonias. The Na+-K+ pump has been shown to control and set the intrinsic activity mode of cerebellar Purkinje neurons. This suggests that the pump might not simply be a homeostatic, "housekeeping" molecule for ionic gradients; but could be a computational element in the cerebellum and the brain.