What is Parkinson disease?
Parkinson disease (or, simply, Parkinson) is the most common form of parkinsonism, a group of motor system disorders. It is a slowly progressing, degenerative disease caused by the loss of dopamine-producing brain cells. Dopamine is a substance produced in the body that has many effects, including smooth and coordinated muscle movement. It is usually associated with the following symptoms:
- Tremor or trembling of the arms, jaw, legs, and face
- Stiffness or rigidity of the limbs and trunk
- Slowness of movement (bradykinesia)
- Impaired balance and coordination
Parkinson's is also called primary parkinsonism or idiopathic Parkinson disease. (Idiopathic is the term for a disorder for which no cause has yet been identified.)
What causes Parkinson disease?
The specific cause of Parkinson is unknown; however, medical experts believe the symptoms are related to a chemical imbalance in the brain caused by brain-cell death. Parkinson is chronic, and symptoms grow worse over time.
Although the disease may appear in younger people (even teenagers), it usually affects people in late middle age. It is not contagious.
Environmental causes are being researched and the strong consistent findings are that rural living, exposure to well water, and exposure to agricultural pesticides and herbicides are related to Parkinson. It is important to remember, however, that these factors do not guarantee the development of the disease, nor does their absence prevent it. Currently researchers believe that in most people the cause of Parkinson’s is a combination of genetics and environmental exposure.
In the other forms of parkinsonism, either the cause is known or suspected, or the disorder occurs as a secondary effect of another primary neurological disorder that may have symptoms of Parkinson's disease. These forms, described as Parkinson syndrome, atypical Parkinson, or, simply, parkinsonism, may be caused by the following:
- Tumors in the brain
- Repeated head trauma, such as may occur in boxing
- Drug-induced parkinsonism. This occurs due to the prolonged use of tranquilizing drugs, such as the phenothiazines, butyrophenones, reserpine, and the commonly used drug, metoclopramide for stomach upset.
- Toxin-induced parkinsonism. This occurs due to manganese and carbon monoxide poisoning.
- Postencephalitic parkinsonism. A viral disease that causes "sleeping sickness."
- Striatonigral degeneration. The substantia nigra of the brain is only mildly affected, while other areas of the brain show more severe damage.
- Parkinson may accompany other neurological conditions such as Shy-Drager syndrome,, progressive supranuclear palsy, Wilson disease, Huntington's disease, Hallervorden-Spatz syndrome, Alzheimer's disease, Creutzfeldt-Jakob disease, olivopontocerebellar atrophy, post-traumatic encephalopathy, and dementia with Lewy bodies.
What are the risk factors for Parkinson disease?
The biggest risk factor for developing Parkinson is advancing age. The average age for the onset of Parkinson is 60 years. In addition, men are affected than women. However, the reason for this is unclear.
Family history is another important risk factor. A person with a parent or sibling affected have approximately two times the chance of developing Parkinson. This increased risk is most likely because of a combination of environmental and genetic factors. Having one or more close relatives with Parkinson increases the risk of developing the disease; however, unless there is a known genetic mutation for Parkinson present, the increased risk is only 2% to 5%.
What are the symptoms of Parkinson disease?
The following are the most common symptoms of Parkinson. However, each person may experience symptoms differently. Symptoms may include:
- Muscle rigidity. Stiffness when the arm, leg, or neck is moved back and forth.
- Resting tremor. Tremor (involuntary movement from contracting muscles) that is most prominent at rest.
- Bradykinesia. Slowness in initiating movement.
- Postural instability. Poor posture and balance that may cause falls; gait or balance problems.
Symptoms of Parkinson vary from person to person. The symptoms may appear slowly and in no particular order. Early symptoms may be subtle and may progress over many years before reaching a point where they interfere with normal daily activities.
Other symptoms are divided into motor (movement-related) and non-motor symptoms.
- Motor symptoms:
- Slow movement (bradykinesia)
- Rigidity and freezing in place
- Stooped posture
- Shuffling gait
- Decreased arm swing when walking
- Difficulty rising from a chair
- Small, cramped handwriting (micrographia)
- Lack of facial expression
- Slowed activities of daily living (for example, eating, dressing, and bathing)
- Difficulty turning in bed
- Remaining in a certain position for a long period of time
- Non-motor symptoms
- Diminished sense of smell
- Low voice volume (hypophonia)
- Difficulty speaking (dysarthria)
- Painful foot cramps
- Sleep disturbance
- Emotional changes (fearful and insecure)
- Skin problems
- Increased sweating
- Urinary frequency/urgency
- Male erectile dysfunction
As the disease progresses, walking may become affected, causing the person to stop in mid-stride or "freeze" in place, and maybe even fall over. People also may begin walking with a series of quick, small steps as if hurrying forward to keep balance, a practice known as festination.
The symptoms of Parkinson may resemble other conditions or medical problems. Always consult your health care provider for a diagnosis.
How is Parkinson disease diagnosed?
Making an accurate diagnosis in the early stages of Parkinson can be difficult, as the beginning signs and symptoms may look like other conditions or the effects of normal aging. For this reason, observation may be required for some time until the symptoms are consistently present.
Currently, there are no blood or lab tests that are useful in the diagnosis of Parkinson. Diagnosis of Parkinson is based primarily on a medical history and thorough neurological exam. Brain scans and/or lab tests may be done to help rule out other diseases or conditions, but brain scan generally will turn out to be normal with Parkinson.
Methods to diagnose Parkinson include:
- Neurological exam (including evaluation of symptoms and their severity)
- Trial test of drugs. When symptoms are significant, a trial test of drugs (primarily levodopa [L-dopa]) may be used to further diagnose the presence of Parkinson’s. If symptoms aren’t relieved from the use of levodopa, a diagnosis of Parkinson's may be questionable.
- Computed tomography scan (also called a CT or CAT scan). A diagnostic imaging procedure that uses a combination of X-rays and computer technology to produce horizontal, or axial, images (often called slices) of the body. A CT scan shows detailed images of any part of the body, including the bones, muscles, fat, and organs. CT scans are more detailed than general X-rays.
- Magnetic resonance imaging (MRI). A diagnostic procedure that uses a combination of large magnets, radiofrequencies, and a computer to produce detailed images of organs and structures within the body.
How is Parkinson disease treated?
Specific treatment for a Parkinson will be determined by your health care provider based on:
- Your age, overall health, and medical history
- Extent of the condition
- Type of condition
- Your tolerance for specific medications, procedures, or therapies
- Expectations for the course of the condition
- Your opinion or preference
So far, there is no cure for Parkinson. However, based on the severity of the symptoms and medical profile, the health care provider will establish an appropriate treatment protocol. Treatment for Parkinson may include the following:
- Complementary and supportive therapies, such as diet, exercise, physical therapy, occupational therapy, and speech therapy
Once the diagnosis has been made, the next decision is whether medication is an option, which depends on the following:
- The degree of functional impairment
- The degree of cognitive impairment
- Ability to tolerate antiparkinsonian medication
- The advice of the attending doctor
No two people react the same way to a given drug; therefore, it takes time and patience to find an appropriate medication and dosage to alleviate symptoms.
Based on the severity of the condition and the medical profile, surgery may be recommended for Parkinson disease.
There are several types of surgery that may be done that can help people with Parkinson disease. Most of the treatments are aimed at helping the tremor or rigidity that comes with the disease. In some people, surgery may decrease the amount of medication that is needed to control the symptoms of Parkinson.
There are three types of surgeries that may be performed for Parkinson disease, including the following:
- Lesion surgery (burning of tissue). In this procedure, small lesions are made in the deep parts of the brain that help control movement. The surgery may be done while the person is awake to help determine the exact placement of the lesion. The lesion is placed to help control, or stop, the area of the brain that is causing the tremor.
- Deep brain stimulation (DBS). With this type of surgery, a small electrode is placed in the deep parts of the brain that help control movement. The electrode is attached to a small battery in the chest wall and is connected by wires that are placed under the skin. The stimulator is then turned on and interrupts the normal flow of information in the brain and can help to decrease symptoms of Parkinson's.
- Neural grafting or tissue transplants. Experimental research is being done to find a replacement for the part of the brain that functions improperly in Parkinson's.
It is important to remember that surgery may help with symptoms of Parkinson, but does not cure the disease or stop its progression.
Living with Parkinson disease
Although Parkinson is a chronic, progressive disease, treatment can help minimize symptoms. It is also important to eat a healthy diet and maintain mobility with the use of assistive devices, if needed. Regular exercise, physical therapy, occupational therapy, and speech therapy can promote independence. Talk with your health care provider about depression, anxiety, or other mental health issues that may arise.
- Parkinson is a slowly progressive, degenerative motor system disorder.
- The most common symptoms are muscle rigidity, resting tremor, slowness in initiating movement, and postural instability.
- There is no known cure for Parkinson’s but medications and surgery can help control symptoms.
- Proper diet, regular exercise, physical therapy, occupational therapy, and speech therapy can promote independence.
Tips to help you get the most from a visit to your health care provider:
- Before your visit, write down questions you want answered.
- Bring someone with you to help you ask questions and remember what your provider tells you.
- At the visit, write down the names of new medicines, treatments, or tests, and any new instructions your provider gives you.
- If you have a follow-up appointment, write down the date, time, and purpose for that visit.
- Know how you can contact your provider if you have questions.
Online Medical Reviewer:
Foster, Sara, RN, MPH
Online Medical Reviewer:
Freeborn, Donna, PhD, CNM, FNP
Date Last Reviewed:
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