|In the News
People with a family history of Parkinson's disease may have an added susceptibility to the disease after pesticide exposure or head trauma In a recent case-control study of nearly 1,000 patients with Parkinson's disease or parkinsonism and almost 2,000 controls, high exposure to pesticides increased the risk of the disease by 41%. Pesticide exposure has been linked to neurological disorders and other diseases. It is not clear exactly which toxins are at fault, and what level of exposure is required to cause harm. Also, a history of traumatic head blows causing a loss of consciousness, a common occurrence in boxing and other sports, was associated with a 2.5-fold greater risk of developing Parkinsons, the authors reported. Even a single blow to the head causing loss of consciousness may increase the risk of Parkinson's disease and related disorders. Occup Environ Med, BMJ May 2007
Exposure to pesticides increases the risk of Parkinson's disease by 70%
A recent study strengthens the mounting evidence that certain pesticides used in agriculture and home insect control are associated with the development of Parkinson's disease. In a recent study from Harvard, 140,000 men and women were followed through 2001 as part of a cancer prevention study. Those who reported being exposed to pesticides or herbicides before 1982 had a 70% higher rate of Parkinson's disease 10 to 20 years after the initial exposure. The incidence was highest among people who had experienced occupational exposure to pesticides such as farmers and ranchers. Farmers not exposed to pesticides did not have a higher incidence of Parkinson's disease. There were no significant associations between Parkinson's disease and other occupational exposures to such toxins as asbestos, acids and solvents, coal, stone dust, or other materials.
Symptoms of pesticide exposure can include respiratory problems, gastrointestinal disease, headache, dizziness, confusion, skin problems, eye problems, and many other nonspecific conditions.
MedPage Today June 2006
|About Parkinson's Disease
|Parkinson's disease is a slowly progressive
neurological disorder that results from degeneration of neurons
in a region of the brain that controls movement, muscle control
and balance. This degeneration creates a shortage of dopamine (a
neurochemical) throughout the brain. This decrease in
dopamine results in the movement impairments that
characterize the disease.
| Secondary Parkinsonism
|This is a similar condition of nerve cell death. The
symptoms are similar to Parkinson's Disease but the etiology of
the nerve cell death can be traced to a specific cause such as:
antipsychotic drugs (i.e. Haldol), carbon monoxide poisoning,
manganese poisoning, hydrocephalus, brain tumors, stroke,
encephalitis, meningitis, IV drug abuse of N-MTP, and reserpine.
Symptoms of Parkinson's Disease
Frequently, the first symptom of Parkinson's
disease is tremor (trembling or shaking) of a limb, especially
when the body is at rest. The tremor often begins on one side of
the body, frequently in one hand.
Other common symptoms include slow movement (bradykinesia),
an inability to move (akinesia), rigid limbs, a shuffling gait,
and a stooped posture. People with Parkinson's disease often
show reduced facial expressions and speak in a soft voice.
Occasionally, the disease also causes depression, personality
changes, dementia, sleep disturbances, speech impairments, or
The severity of Parkinson's symptoms tends
to worsen over time.
Incidence of Parkinson's Disease
In the United States, more than 1.5 million people are believed
to be affected by Parkinson's disease. These figures are
expected to increase as the average age of the population
increases. The disorder appears to be slightly more common in
men than women. The average age of onset is about 60. Both
prevalence and incidence increase with advancing age; the rates
are very low in people under 40 and rise among people in their
70s and 80s. However, there is an
alarming increase of patients of younger age.
Causes of Parkinson's Disease
The cause of Parkinson's Disease is unknown. Although
there are many theories, none have ever been proven.
Recent studies have
suggested that some people have an inherited susceptibility to
the disease which is further influenced by environmental factors.
Diagnosis of Parkinson's Disease
|There is no test that can clearly identify the disease.
Parkinson's disease is usually diagnosed by a neurologist who
can evaluate symptoms and their severity. Sometimes people
with suspected Parkinson's disease are given anti-Parkinson's
drugs to see if they respond. Other tests, such as brain scans,
can help doctors decide if a patient has true Parkinson's
disease or some other disorder that resembles it. Microscopic
brain structures called Lewy bodies, which can be seen only
during an autopsy, are regarded as a hallmark of classical
Treatment for Parkinson's Disease
There is no cure for Parkinson's disease. But, with
proper treatment, people with Parkinson's can lead long and
productive lives. The progression of the disease varies from
individual to individual, however, so treatment is
Initially, many patients are only mildly affected
and need no symptomatic treatment for several years.
symptoms begin with tremor. As a rule, resting tremor is rarely
disabling for most patients. Patients should try not to force the
doctor to treat tremor early on just to avoid some perceived
embarrassment unless there is accompanying functional disability
from the tremor.
The reason for
this is that although the initial response to symptomatic
treatment can be dramatic, over time the effectiveness of
drugs frequently decline and their side effects can worsen. Because
of these eventual problems, conservative lifestyle changes are
initially recommended to control symptoms reserving the use of
medications for later in the disease. Physical therapy, as well as
a healthy diet and regular exercise can provide significant relief
of symptoms early in the disease.
therapy can help improve mobility, range of motion, muscle strength,
endurance and balance. Exercise can make a significant difference in the persons general well being and
quality of life. Also, for many people, working with a speech
pathologist can help improve problems with speaking and swallowing.
major question that
faces patients and physicians is when to start treatment and with
what drug in a patient newly-diagnosed with PD. Most PD experts
agree that treatment should not be started until a patient is
experiencing some “functional disability” from the disease.
The following is a list of the categories of drugs
used in treating the symptoms of Parkinson's. Some new drugs have recently been
approved offering a wider choice of medications,
while others are under investigation in this country and overseas in
an effort to obtain better therapeutic results with fewer side
Levodopa is a natural substance found in
plants and animals and is the
most important and most effective drug to treat the symptoms of PD.
Levodopa helps all the major signs and symptoms in the majority of
patients. In fact, if a patient is not helped by levodopa, this is
often evidence that the patient may be suffering from one of the
other forms of parkinsonism described earlier. Nausea is the most
common side-effect experienced by patients who take levodopa. With
persistence, most patients can overcome this problem (see below). The simultaneous administration
with levodopa with an additional drug allows a higher
concentration of levodopa to reach the brain and also considerably
decreases the side effects of levodopa.
of the nausea many patients experience when taking levodopa alone, it
is usually taken in combination with
Carbidopa markedly reduces the incidence of nausea and vomiting from
levodopa. It also ensures that more levodopa goes into the brain
Patients taking the combination require less levodopa per dose
than if they take levodopa alone. For these reasons it is the most
common form in which patients take levodopa.
Levodopa/carbidopa comes in two forms, standard and
controlled-release(CR). The standard form is absorbed quickly while the CR form is absorbed over several
hours. Many patients who develop end-of-dose wearing-off symptoms
are helped by switching from the regular to the CR form of levodopa.
levodopa product that contains entacapone, Stalevo has a unique ingredient that
helps levodopa work better for longer periods of time. People who
take Stalevo may have better symptom control for longer periods of
time between doses of levodopa, which improves activities of daily
living. Just as carbidopa blocks the conversion of levodopa to
dopamine in the blood and intestine, entacapone inhibits an enzyme
that blocks levodopa breakdown in the blood. A more consistent level
of levodopa in the blood may result in better and reliable control
Selegiline (Deprenyl, Eldepryl)
By interfering with one of the enzymes that break down dopamine
enhance and prolong the effect of each dopamine molecule. It was
once hoped that selegiline might slow the progression of PD, but few
physicians still believe this to be the case. It is used frequently
as a first drug for the treatment of early PD and seems to be of
moderate help to about 60% of such patients. This benefit is
sufficient to satisfy most patients for approximately one year,
after which they may elect to start levodopa treatment, either by
adding levodopa to selegiline or by switching to levodopa
preparation. Some patients encounter difficulty sleeping when they
take selegiline. Therefore, it is usually given at breakfast and
lunch but not bedtime. In patients with more advanced disease,
adding selegiline to levodopa may help those experiencing end-of
dose failure using levodopa alone. In these patients, adding
selegiline may worsen or bring on high dopa or peak-dose dyskinesias
(see previous sections for definitions).
Dopamine receptor agonists:
pergolide (Permax®), bromocriptine (Parlodel®) , pramipexole (Mirapex®)
and ropinirole (Requip®). These are synthetic compounds that mimic
the action of dopamine in the basal ganglia. These agents are
usually used in addition to levodopa for patients who experience
end-of-dose failure on levodopa alone or might be used initially in
early Parkinson's Disease, especially in younger adults.
side effects of dopamine agonists are similar to those of levodopa,
such as nausea, although they are less likely to cause involuntary
movements and more likely to cause hallucinations and nightmares. Thus, major side effects include nausea, nightmares and
hallucinations. Patients who have already experienced
hallucinations or confusion should avoid using this class of drugs.
COMT inhibitors (Stalevo) and Tolcapone (Tasmar)
These drugs prolong the effect of levodopa therapy by blocking an
enzyme that breaks down dopamine in the liver and other organs.
Tolcapone (Tasmar) is a potent COMT inhibitor that easily crosses
the blood-brain barrier. But because Tasmar has been linked to liver
damage and liver failure, the drug is normally used only in people
who aren't responding to other therapies. Entacapone is a COMT
inhibitor that shares some of the properties of tolcapone but
doesn't cross into the brain. It may help manage fluctuations in the
response to levodopa in people with Parkinson's disease. Entacapone
doesn't cause liver problems and is now combined with carbidopa and
levodopa in a medication called Stalevo.
trihexyphenidyl (Artane) and benztropine (Cogentin), are available.
The antihistamine diphenhydramine (Benadryl and antidepressants such
as amitriptyline (Elavil) work much like anticholinergics and may be
used in older adults who can't tolerate anticholinergics themselves. These drugs
were the main treatment for Parkinson's disease before the
introduction of levodopa. In general, they help control tremors in
the early stages of the disease. Even so, they're only mildly
beneficial and sometimes the benefits are offset by side effects
such as dry mouth, nausea, urine retention — especially in men with
an enlarged prostate — and severe constipation. Antcholinergics can
also cause mental problems, including memory loss, confusion and
Amantadine (Symmetrel, Symadine)
This antiviral drug may be prescribed for people in the latter
stages of Parkinson's disease, especially if they have problems with
involuntary movements induced by levodopa (dyskinesia). Side effects
include swollen ankles and a purple mottling of the skin.
Depending upon the patient's specific condition, one
of the following procedures may be considered:
Deep Brain Stimulation involves implanting a brain stimulator, similar to a heart pacemaker, in
certain areas of the brain. For some people, this may control
symptoms so well that medications can be greatly reduced.
to read more about Deep Brain
Stimulation at the website of The National Institute of
Neurological Disorder and Stroke.
This is a form of brain surgery that has been effective in
reducing symptoms in patients who are severely affected.
This is done less frequently today, however, because of the risk
of serious side effects and the availability of deep brain
Thalamotomy It is thought that the abnormal
brain activity that causes tremor is processed through the
thalamus. Thalamotomy destroys part of the thalamus to block the
abnormal brain activity from reaching the muscles and causing
Although thalamotomy and pallidotomy surgeries are still done
today, they are done less frequently because of the risk of
serious side effects and the availability of
deep brain stimulation, which is safer and has fewer
Support Groups in
Pinellas County, Florida:
| APDA Suncoast Parkinsonian Chapter/Support
St. Luke's United Methodist Church,
4444 Fifth Ave. N, St. Petersburg. Call (727)
Barrington, 901 Seminole Blvd., Largo Call (727) 585-5900
Edward White Hospital auditorium,
2299 Ninth Ave N, St. Petersburg.
Call 727-867-6719 or 727-321-0984
Parkinson's Disease Support Group for ages
60 and younger "Movers and Shakers"
Seminole Community Library, 9200 113th St. N, Seminole
Call Jackie (727) 397-2024
Hospital, 901 Clearwater-Largo Rd, Largo,
Call (727) 588-3405
Parkinson's Disease Support Group
Cypress Palms of Largo, 400
Lake Avenue, NE, Largo. Call (727)-437-1600
|Written by N Thompson, ARNP, MSN, in collaboration with M Thompson, MD, Internal Medicine, Last updated May 2007
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