Pinky S. Tiwari, M.D., P.A.
Telephone: (713) 790
Diplomate, American Board of Neurology
Diplomate, American Board of Electrodiagnostic Medicine
– 1775
St. Luke’s Medical Tower
6624 Fannin, Suite 2190
Houston, TX 77030
www.texasneuro.com Fax: (713) 790 – 1605
Parkinson's disease is a serious disorder that affects nerve cells (neurons) in the part of the brain controlling muscle movement. Nearly one million Americans currently live with Parkinson's and approximately 50,000 more receive a diagnosis of the disease every year.
People with Parkinson's often experience trembling, muscle rigidity, difficulty walking, and problems with balance and coordination. These symptoms generally develop after age 50, although the disease affects a small percentage of younger people as well.
Parkinson's disease is progressive, meaning the symptoms become worse over time. But although Parkinson's may eventually be disabling, the disease often progresses gradually, and most people have many years of productive living after a diagnosis.
Furthermore, unlike other serious neurologic diseases, Parkinson's disease is treatable. For decades, the drug levodopa, commonly known as L-dopa, was the mainstay of Parkinson's disease treatment. L-dopa can cause side effects, however, and tends to become less effective when taken for prolonged periods. For that reason newer drugs are now also used — either alone or in combination with levodopa.
Another treatment that has had encouraging results is deep brain stimulation (DBS). DBS involves implanting a brain stimulator, similar to a heart pacemaker, in certain areas of the brain. For some people, DBS may control symptoms so well that medications can be greatly reduced. Meanwhile, research into other therapies, including stem cell implants, is ongoing.
Signs and symptoms
The earliest symptom of Parkinson's disease can be as subtle as an arm that doesn't swing when you walk, a mild tremor in the fingers of one hand or soft, mumbling speech that's difficult to understand. You also may lack energy, feel depressed or have trouble sleeping. Or you may notice that it takes you longer to shower, shave, eat or do other routine tasks.
Other signs and symptoms of Parkinson's disease may include:
 Tremors. These often start with a slight shaking in one finger that later may spread to the whole arm.
Sometimes hand tremors cause a back-and-forth rubbing of the thumb and forefinger known as pill rolling. Tremors also may develop in the head, lips or feet. These symptoms may occur on one or both sides of your body and may be more noticeable when you're under stress. Although tremors can be very distressing, they're usually not disabling and often disappear during sleep.
 Slowed motion (bradykinesia). Over time, Parkinson's disease may cause a slow, shuffling walk with an unsteady gait and stooped posture. And certain muscles may freeze up, making it hard to resume normal movement. This is especially distressing because it can make performing the simplest tasks difficult and time-consuming. Even the functioning of the digestive tract may slow down, causing problems with swallowing, digestion and elimination. Constipation is often a major problem for people
 with Parkinson's disease.
Rigid muscles. Muscle stiffness (rigidity) often occurs in the limbs and neck. Sometimes the stiffness can be so severe that it limits the size of movements.

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Loss of automatic movements.
Blinking, smiling and swinging your arms when you walk are all unconscious acts that are a normal part of being human. In Parkinson's disease, these acts tend to be lost. Some people may develop a fixed staring expression and unblinking eyes. Others may no longer gesture or seem animated when they speak.
Impaired speech.
Many people with Parkinson's disease have some trouble speaking, and their voices often become monotonous and very soft. This may be a special problem for older adults because the soft voice of a person with Parkinson's disease may not be audible to a spouse with poor hearing.
Difficulty swallowing. This is common in the later stages of the disease.
Causes
In the nearly 200 years since Parkinson's disease was first described, researchers have come to understand some of the processes of this complex disorder. They now know that Parkinson's disease occurs when certain neurons in an area of the brain called the substantia nigra are damaged or destroyed. Normally, these nerve cells release dopamine — a chemical that transmits signals between the substantia nigra and another part of the brain, the corpus striatum. These signals cause your muscles to make smooth, controlled movements.
Everyone loses some dopamine-producing neurons as a normal part of aging. But people with Parkinson's disease lose at least 60 percent of neurons in the substantia nigra. Just what causes this is a subject of intense research. Right now scientists believe Parkinson's disease may result from a combination of genetic and environmental factors. Certain drugs, diseases and toxins also may cause symptoms similar to those of
Parkinson's disease.
Genetic factors
Until recently, scientists believed that genes played a role primarily in an unusual type of Parkinson's disease that affects young people. But new research shows that a strong genetic component also occurs in older adults. In fact, people who have a first degree relative with Parkinson's disease, such as a parent, sibling or child, are at three times greater risk of developing the disease themselves, regardless of their age. And one study found that having two first degree relatives with Parkinson's disease can increase risk as much as 10 times.
Environmental factors
People with unusual exposure to herbicides and pesticides are three times more likely to develop Parkinson's disease than people who don't have this exposure. Unfortunately, researchers haven't yet been able to connect a specific herbicide or pesticide to the disease.
In one study, a combination of the herbicide paraquat and the fungicide maneb — chemicals commonly used together on crops throughout the United States — was found to damage the same part of the brain in mice that's affected in people with Parkinson's disease. But the study failed to provide conclusive evidence that exposure to paraquat and maneb cause Parkinson's.
Medications
A number of drugs taken for long periods of time or in excessive dosages can cause symptoms of Parkinson's disease. These include medications such as haloperidol (Haldol, Halperon) and chlorpromazine (Thorazine,
Sonazine), which are prescribed for certain psychiatric disorders, as well as drugs used to treat nausea, such as metoclopramide (Reglan) and prochlorperazine (Compazine, Compro). The epilepsy drug valproate
(Depacon) may also cause some of the features of parkinsonism, especially severe tremors.
Toxins
Exposure to toxins such as manganese dust or the chemical MPTP, a byproduct of heroin production, can lead to parkinsonism. Scientists first became aware of MPTP-induced parkinsonism in the 1980s when heroin addicts using a street drug contaminated with MPTP developed all of the symptoms of Parkinson's disease. These cases are rare, however.

Risk factors
Age is one of the main risk factors for Parkinson's disease. Although the disease can affect adults in their 20s, it ordinarily starts in middle or late life. The risk continues to increase with age. Some researchers theorize that people with Parkinson's disease may have neural damage from genetic or environmental factors that becomes worse over time.
Other risk factors include:
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Heredity.
Having one close relative with Parkinson's increases the chances that you'll also develop the disease. If you have two or more close relatives with Parkinson's, your risk increases ten-fold.
Exposure to pesticides and herbicides.
Direct contact with herbicides and pesticides puts you at increased risk of Parkinson's. The disease is also more common in people who are involved in farming, live in a rural area or drink well water. It's likely that herbicide and pesticide exposure plays a role in these cases as well.
Reduced estrogen levels.
Reduced estrogen levels may increase the risk of Parkinson's disease. This means that menopausal women who receive little or no hormone replacement therapy (HRT) and those who have had hysterectomies may be at higher risk. Menopausal women using HRT appear to have a decreased risk. But not all effects of HRT are positive. Taking HRT as a combination therapy — estrogen plus progestin — can result in serious side effects and health risks. Work with your doctor to evaluate the options and decide what's best for you.
Reduced folate levels.
Results of studies published in the January 2002 issue of the Journal of
Neurochemistry suggest that low levels of the B vitamin folate (the synthetic form is known as folic acid) may increase susceptibility to Parkinson's disease. Researchers found that mice with low folate levels developed severe Parkinson's symptoms, while those with normal levels remained healthy. Scientists speculate that consuming adequate amounts of folate or folic acid may help protect older adults from
Parkinson's disease as well as from other degenerative neurologic diseases. Folate naturally occurs in dark green vegetables such as spinach, in citrus fruits, and in whole-wheat bread. Half a cup of cooked spinach contains about 130 micrograms of folate. The Food and Drug Administration (FDA) also requires that folic acid be added to enriched bread, pasta and rice.
Parkinson Foundation of Harris County
7457 Harwin, Suite 308
Houston, Texas 77036-2025