Parkinson's Disease (PD)
What is PD?
Parkinson's disease (or, simply, Parkinson's) is the most common form of parkinsonism, a group of motor system disorders. It is a slowly progressing, degenerative disease that is usually associated with the following symptoms, all of which result from the loss of dopamine-producing brain cells:
Tremor or trembling of the arms, jaw, legs, and face
Stiffness or rigidity of the limbs and trunk
Bradykinesia (slowness of movement)
Postural instability, or impaired balance and coordination
Dopamine is a substance produced in the body that has many effects, including smooth and coordinated muscle movement.
What are the facts about PD?
It is a myth that Parkinson's disease was cured after the introduction of levodopa (L-dopa) in the 1960s. In fact, about 60,000 Americans are newly diagnosed with Parkinson's disease each year, and more than 1 million Americans affected at any one time. in addition, more people suffer from Parkinson's disease than multiple sclerosis, muscular dystrophy, and amyotrophic lateral sclerosis combined.
What causes PD?
The specific cause of PD is unknown; however, medical experts believe the symptoms are related to a chemical imbalance in the brain caused by brain-cell death. Parkinson's disease is chronic (persists over a long period of time), and progressive (symptoms grow worse over time).
Although the disease may appear in younger patients (even teenagers), it usually affects people in late middle age. It is not contagious.
The biggest risk factor for developing PD is advancing age. The average age for the onset of PD is 60 years. In addition, 50 percent more men are affected than women, according to the National Institute of Neurological Disorders and Stroke. However, the reason for this is unclear.
Family history is another important risk factor. Individuals with a parent or sibling who are affected have approximately two times the chance of developing PD. This increased risk is most likely because of a combination of environmental and genetic factors.
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 PD. It is important to remember, however, that these factors do not guarantee the development of PD, nor does their absence prevent it. Having one or more close relatives with PD increases one's risk of developing the disease; however, unless there is a known genetic mutation for PD present, the increased risk is only 2 to 5 percent.
Currently researchers believe that in most individuals the cause of PD is a combination of genetics and environmental exposure.
Parkinson's syndrome, atypical Parkinson's, or parkinsonism
Parkinson's disease is also called primary parkinsonism or idiopathic Parkinson's disease. (Idiopathic is the term for a disorder for which no cause has yet been identified.)
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 both primary and secondary symptoms of Parkinson's disease. These disorders, described as Parkinson's syndrome, atypical Parkinson's, or, simply, parkinsonism, may include the following:
Tumors in the brain
Repeated head trauma
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.
Parkinsonism that accompanies other neurological conditions. Examples of this are Shy-Drager syndrome, (multiple system atrophy, once thought to be a distinct disease, is now commonly thought to be simply an extensive progression of idiopathic PD), 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 four primary symptoms of PD?
The following are the most common symptoms of Parkinson's disease. However, each individual 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.
Are there other symptoms of PD?
Symptoms of Parkinson's disease vary from patient to patient. 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.
The four cardinal symptoms of PD are listed above. Other symptoms are divided into motor (movement-related) and nonmotor symptoms.
Bradykinesia (slow movement)
Rigidity and freezing in place
Decreased arm swing when walking
Difficulty rising from a chair
Micrographia (small, cramped handwriting)
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
Diminished sense of smell
Low voice volume (hypophonia)
Difficulty speaking (dysarthria)
Painful foot cramps
Emotional changes (fearful and insecure)
Male erectile dysfunction
As the disease progresses, walking may become affected, causing the patient to stop in mid-stride or "freeze" in place, and maybe even fall over. Patients 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's disease may resemble other conditions or medical problems. Always consult your doctor for a diagnosis.
How is PD diagnosed?
Making an accurate diagnosis in the early stages of Parkinson's disease can be difficult, as the beginning signs and symptoms may be considered to be indications of other conditions or the effects of normal aging. For this reason, observation of the patient may be required for some time until the symptoms are consistently present.
Currently, there are no blood or laboratory tests that are useful in the diagnosis of PD. Diagnosis of PD is based primarily on a medical history and thorough neurological examination. Brain scans and/or lab tests may be performed to help rule out other diseases or conditions, but brain scan generally will turn out to be normal with PD.
Methods to assist with the diagnosis of PD include:
Neurological examination (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 PD. If a patient fails to benefit from levodopa, a diagnosis of Parkinson's disease 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.
What is the treatment for PD?
Specific treatment for a Parkinson's disease will be determined by your doctor 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
With today's medicine, we have yet to find a cure for Parkinson's disease. However, based on the severity of the symptoms and medical profile, the doctor will establish an appropriate treatment protocol. Treatment for Parkinson's disease may include the following:
Complementary and supportive therapies, such as diet, exercise, physical therapy, occupational therapy, and speech therapy
Medication for PD
Once the diagnosis of PD has been made, the next decision is whether a patient should receive medication, 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 patients react the same way to a given drug, therefore, it takes time and patience to find an appropriate medication and dosage to alleviate symptoms.
Surgery for PD
Based on the severity of the condition and the medical profile, the doctor may recommend surgery as one treatment option for Parkinson's disease.
There are several types of surgery that may be performed that can help patients with Parkinson's disease. Most of the treatments are aimed at helping the tremor or rigidity that comes with the disease. In some patients, surgery may decrease the amount of medication that is needed to control the symptoms of Parkinson's disease.
There are three types of surgeries that may be performed for Parkinson's disease, including the following:
Lesion surgery (burning of tissue). In this procedure, deep parts of the brain are targeted and small lesions are made in critical parts of the brain that help control movement. The surgery may be done while the patient 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 critical parts of the brain that help to 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 disease.
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 disease.
It is important to remember that surgery may help with symptoms of Parkinson's disease, but does not cure the disease or stop the progression of the disease.