A number of uncommon toxins are capable of causing brain damage centered in the motor control region known as the basal ganglia. Dystonia may be one prominent feature experienced by people with these exposures, but it is extremely uncommon for "pure dystonia" to be seen in such patients. In other words, the vast majority of people exposed to toxins (for example, manganese, cyanide, 3-nitropropionicacid) have additional neurological problems associated with the dystonia. Possibly the most common feature in such patients is the presence of parkinsonism
Diagnosis
Many of the ascribed causes of secondary dystonia are based on historical information or subtle characteristics of the symptoms, and have no diagnostic, radiologic, serologic, or other pathologic trademark
Treatment
Oral medications are often the mainstay of treatment for secondary dystonia. Although there is no single drug that helps an overwhelming number of individuals, there are several that may be of benefit. These oral medications include levodopa, trihexyphenidyl, clonazepam, and baclofen (oral and intrathecal—especially for dystonia and spasticity). Medications may be taken in combination
Botulinum toxin injections may be used to treat specific body parts that may be affected, such as the neck, jaw, hands, or feet
Several surgical techniques may be appropriate for select individuals who do not respond to medications and botulinum toxin injections. These include ablative surgeries such as pallidotomy and thalamotomy, intrathecal baclofen, and deep brain stimulation
