Overview, Causes, & Risk Factors

Parkinson's disease is a progressive disorder caused by degeneration of nerve cells in the part of the brain that controls movement.

What is going on in the body?

Parkinson's disease involves a breakdown of the nerve cells in the motor area of the brain. As the cells break down, there is a shortage of dopamine. Dopamine is a neurotransmitter, or chemical that carries messages to the body. When there is a shortage of dopamine, the messages that regulate movement aren't sent properly.

What are the causes and risks of the disease?

The cause of Parkinson's disease is not known. There may be a hereditary tendency to the disease that is worsened by factors in the environment. Some people with Parkinson's disease have an abnormality on chromosome 4.

There is evidence that Parkinson's disease may be caused by a defect in the body's normal methods for breaking down protein. This defect allows debris to build up in the brain and damage brain cells. The defect may be caused by one or more of the following factors:

The symptoms of Parkinson's disease usually begin at about age 60. It is most common in people in their 70s and 80s. Parkinson's disease is twice as frequent in men than in women. Preliminary research suggests that estrogen, a female hormone, may protect against Parkinson's disease.

Symptoms & Signs

What are the signs and symptoms of the disease?

Parkinson's disease may cause the following:

The tremor of Parkinson's disease often starts on one side in the hand or arm. It usually occurs when a person is still. It can worsen with stress. It usually goes away with sleep. The tremor can occur in one or all of the extremities. It is sometimes seen in the face.

People who have Parkinson's disease may have trouble getting out of a bed or chair. People with the disease often have a unique style of walking. They bend forward, take small steps, shuffle the feet, and have problems with turning. Affected people also have a tendency to fall forward or backward. Some people cannot stop a movement once it has started. A wheelchair may be needed in severe cases.

A person with Parkinson's may complain of being weak or tired. Poor muscle movement in the face can cause a blank look. The person can have difficulty swallowing or speaking. The ability to write, button a shirt, and eat can become impaired.

Following are some of the other symptoms of the disease:

Diagnosis & Tests

How is the disease diagnosed?

Diagnosis of Parkinson's disease begins with a medical history and physical exam. No single test can diagnose the disease. A cranial CT scan can appear normal in the early part of the disease. Brain shrinkage and damage will appear later. The healthcare provider may prescribe antiparkinsonian medications to see if the person's symptoms respond to medication. A positive response would support a diagnosis of Parkinson's disease.

Prevention & Expectations

What can be done to prevent the disease?

Because the cause is not known, there is no known way to prevent Parkinson's disease. Avoiding exposure to environmental toxins, such as pesticides, may be helpful. There is very preliminary information that hormone replacement therapy, or HRT, in women may help prevent Parkinson's disease. Women may want to discuss HRT with their healthcare providers.

What are the long-term effects of the disease?

Parkinson's disease is a progressive, degenerative disease. This means that symptoms continue to get worse and new symptoms are seen.

What are the risks to others?

Parkinson's disease is not contagious and poses no risk to others.

Treatment & Monitoring

What are the treatments for the disease?

There is no cure for Parkinson's disease. The major goal of treatment is to prevent deterioration. Symptoms can usually be well controlled for several years in the early stages of the disease.

Early in the disease, medications are used. One of the most common medicines is a combination of levodopa and carbidopa. Although this combination is effective, it tends to work less and less over time. Other medications used to treat Parkinson's disease include the following:

Another treatment is surgery. Surgery can include removal of a tiny part of the brain. Another approach is deep brain stimulation with electricity.

People may need other treatments to deal with the many problems associated with the disease. If dementia is present, close monitoring may be needed. Treatment with antidepressants, antipsychotic medications, or sedatives can also help relieve some symptoms. Physical and occupational therapy, as well as speech therapy may help. The use of a service dog and in-home care may be needed.

Other medications may be used in late-stage Parkinson's disease to control symptoms. Medicines can be helpful when there are problems with bladder control, for example. Men with Parkinson's disease may be given medications for erectile dysfunction.

Researchers continue to test new treatments for Parkinson's disease. Implanting fetal cells into the brain of people with Parkinson's disease was recently tried and failed. In some people, the treatment caused severe problems with movement.

What are the side effects of the treatments?

Medications used to treat Parkinson's disease may cause abnormal body movements. Other side effects include nausea, drowsiness, confusion, and dry mouth.

Surgery may cause difficulty with speech or paralysis on one side of the body. Deep brain stimulation usually requires more than one operation. There is also a risk of bleeding, infection, or allergic reaction to anesthesia.

What happens after treatment for the disease?

People with Parkinson's disease need treatment for life.

How is the disease monitored?

A family member or caregiver is important when it comes to monitoring Parkinson's disease. They can give the healthcare provider day-to-day input on benefits and side effects of treatment. Any new or worsening symptoms should be reported to the healthcare provider.