What is the difference between a Parkinson's disease patient with dystonia and a dystonia patient with Parkinson's symptoms?

What is the difference between a Parkinson's disease patient with dystonia and a dystonia patient with Parkinson's symptoms?

Parkinson's disease is a neurological movement disorder with a wide array of symptoms that includes slowness of movement, rigidity of muscles, tremor, loss of balance, memory impairment, personality changes, and others. The “movement” symptoms of Parkinson’s disease (slowness of movement, rigidity, tremor, loss of balance) may be called parkinsonism. Parkinsonism is one aspect of Parkinson’s disease.

Symptoms of dystonia and parkinsonism can occur in the same patient because both of these movement disorders seem to arise from involvement of the basal ganglia in the brain. Both parkinsonism and dystonia can each be caused by a great many disorders, and some of these disorders includes features of both parkinsonism and dystonia.

For example, there are the disorders known as dopa-responsive dystonia (DRD) and x-linked dystonia-parkinsonism (XDP). DRD commonly begins in children as a dystonia predominately affecting the feet and being first manifested by an abnormal gait. In these children, features of parkinsonism tend to develop such as slowness of movement and also decreased muscle tone.

When DRD begins in adults, it usually appears first as parkinsonism and can be mistaken for Parkinson's disease. XDP can also first develop as either dystonia or parkinsonism, and the symptoms of other disorder may occur.

In the parkinsonian disorder known as Parkinson's disease, certain features of the disease can be thought of as a form of dystonia. These features include postural changes in the hands and feet and also in the neck. These partial changes are so common that most physicians consider them as part of Parkinson's disease and do not consider them to be a form of dystonia that has developed on top of parkinsonism. In parkinsonian syndromes such as progressive supranuclear palsy, certain features of dystonia may appear (such as dystonia of the facial muscles or the neck muscles).

In primary dystonia, by definition, the patient presents only pure dystonia without any features of parkinsonism. If parkinsonism were to develop in such a patient, it could be considered that this patient happens to have two different disorders. For example, a patient may have adult-onset cervical dystonia in which the neck is twisted and, after several years, develop features of parkinsonism. It is generally believed that cervical dystonia and Parkinson's disease are two separate entities occurring in the same patient.

Some medications might be helpful for both parkinsonism and dystonia symptoms. For example, levodopa is the most effective drug to reverse parkinson symptoms, and it is also very effective in treating DRD and in some patients with other forms of dystonia. Anticholinergic drugs, such as Artane®, are often used to treat dystonia, but they can also help some of the symptoms of parkinsonism. Essentially all the drugs currently in use to treat dystonia were first utilized in the treatment of Parkinson's disease.