Symptoms - Dystonia
Dystonia occurs when the muscles repeatedly or continuously contract and cause repetitive or twisting movements. The sustained muscle contractions are painful, and dystonia can cause abnormal movements or postures. Many different conditions can cause dystonia, including Parkinson’s disease (PD).
An estimated 40 percent of people with PD experience dystonia as a symptom of their condition or as a side effect of treatment, and it seems to be more prominent in people with a mutation in the Parkin gene (one of several genes that has been identified that is connected to PD).1,2
Voluntary movements can worsen dystonia, causing a cascade effect into adjacent muscles. Dystonia may only affect certain areas of the body or may affect multiple areas of the musculature, causing general distortion throughout the body. While dystonia can appear differently across people and has varying levels of severity and pain, the commonalities among all people who experience dystonia are the repetitive, patterned, and frequently twisting uncontrolled muscle contractions.1
What causes dystonia in Parkinson's disease?
The exact disease processes that cause dystonia remain unknown, but it likely is caused by dysfunction in the basal ganglia, an area of the brain that is also affected in Parkinson’s. The basal ganglia are a group of neurons (nerve cells) located deep in the brain that process information on movement and play an important role in planning actions to achieve specific goals, such as using hands to catch a ball or write with a pen. The basal ganglia work in cooperation with the cortex (the outer, convoluted portion of the brain) to signal and activate muscles.2,3
Dystonia may be classified as primary, secondary, or dystonia-plus. In primary dystonia, the dystonia is the only neurological disorder the individual has. Secondary dystonia results from a specific external factor, such as trauma, infections, stroke, or as a side effect from some medications. Dystonia-plus includes dystonia experienced by people with PD, as well as dystonia that results from other neurological disorders.1
There is no cure for dystonia, but there are treatments that can help ease the muscle contractions and pain. Treatment usually includes a combination approach, which may include medications, surgery, and/or complementary therapies.
Some medications used to treat PD can also relieve dystonia, including anticholinergic medications and levodopa. Other medications that may be used to treat dystonia include muscle relaxants or antispasmodic agents and botunlinum toxin injections. Botulinum toxin injections use a small amount of the toxin delivered directly into the affected muscle, where it relaxes the muscle and reduces the excessive contractions.
Deep brain stimulation (DBS) can also help relieve dystonia. DBS is a surgical procedure that is used in neurological disorders like PD and dystonia, in which a battery-powered stimulator is implanted in the chest and delivers electrical stimulation to the brain (like a brain pacemaker).1,2
As with all treatments for PD and its symptoms, people with PD should consult with a movement disorders specialist, who has expertise in treating movement disorders like PD and knows how medications, combinations of drugs, and their potential side effects can affect PD.