Parkinson's Disease
Parkinson's disease (PD) is a slowly progressive, chronic neurological
condition that affects a small area of cells in the mid brain known as
the substantia nigra. Gradual degeneration of these cells causes a reduction
in a vital chemical known as "dopamine".
Signs and Symptoms
This decrease in dopamine can produce one or more of the classic signs
of Parkinson's disease:
- Resting tremor on one side of the body
- Generalized slowness of movement (bradykinesia)
- Stiffness of limbs (rigidity)
- Gait or balance problems (postural dysfunction).
Other symptoms observed in some persons with Parkinson's disease can
include:
- Small cramped handwriting (micrographia)
- Lack of arm swing on the affected side
- Decreased facial expression (hypomimia)
- Lowered voice volume (dysarthria)
- Feelings of depression or anxiety
- Episodes of feeling "stuck in place" when initiating a step (freezing)
- Slight foot drag on the affected side
- Increase in dandruff or oily skin
- Less frequent blinking and swallowing
Few patients experience all of these symptoms and some may experience
other signs.
Occurrence Rate
- Estimated that up to 1.5 million Americans are affected
- 40,000 to 60,000 new cases are diagnosed each year
- 15% of patients are diagnosed before age 50
- Parkinson's disease affects one of every 100 persons over the age
of 60
Thanks to public health strides and healthier lifestyle choices, many
people now live well into their eighties, adding to the impression that
the incidence of Parkinson's disease is increasing. While there is, as
yet no cure for this condition, progressive treatments allow many patients
to maintain a high level of function throughout their lifetimes. It
is crucial to note that Parkinson's disease is not a fatal illness.
Causes
The cause of Parkinson's disease remains a mystery. What happens is
clearer than why it happens in these cases. Cells begin to die in a small
deep area of the brain, the substantia nigra . These cells of
the substantia nigra manufacture dopamine, a chemical messenger that
is necessary for ease of movement. As the cells degenerate, the amount
of dopamine in the brain decreases. Symptoms of Parkinson's appear when
about 70-80% of these cells die. It is not clear why these cells begin
to die in some people but not in others.
Secondary Parkinsonism
Sometimes Parkinson's symptoms can be linked to stroke, or exposure
to certain toxins, or use of medications such as those used to treat
psychosis and some used for nausea. In these cases, the condition is
known as secondary parkinsonism , and the condition may be reversible
if the cause can be eliminated.
Idiopathic Parkinsonism
Most cases of Parkinson's, however, are termed idiopathic ,
or without a known cause.
Recently, researchers isolated a gene responsible for multiple cases
of Parkinson's in a large family. But only 20% of people who have the
illness are thought to have a hereditary connection. Some researchers
are investigating a possible link between Parkinson's and a person's
lifetime exposure to environmental toxins such as pesticides and heavy
metals. Others think PD may be the result of the natural aging process
gone awry, accelerating the normal brain cell death that occurs as we
age. However, most researchers agree that Parkinson's disease is probably
the result of a genetic predisposition coupled with a yet unknown environmental
factor.
Diagnosis
There is no definitive blood test or X-ray to confirm diagnosis. The
diagnosis of Parkinson's disease is one of clinical judgement, based
on a thorough neurological examination. The diagnosis of Parkinson's
based on the person's symptoms, medical history and response to medications.
Tests such as magnetic resonance imaging (MRI), and/or blood work can
help rule out conditions that may produce similar symptoms such as stroke
or a brain tumor. Once a probable diagnosis is established, medications
are prescribed, and the diagnosis is confirmed if the symptoms improve.
Treatment
The goal of treatment is to maximize independence and quality of life
for people who have Parkinson's disease. Treatment may include medication,
surgery, and rehabilitation therapy.
Medications
Medications currently provide the most effective Parkinson's treatment.
There are a variety of medications aimed at controlling and alleviating
the symptoms. Because every person who has Parkinson's has individual
symptoms and responses to medication, treatment is tailored to the individual,
and may require a combination of several different medications.
Surgery
For those whose tremor does not respond to the usual medical treatments,
surgery may be an option. Deep brain stimulation (DBS) surgery involves
placement of a wire electrode into an area of the brain called the thalamus. This
electrode is connected to a stimulator, somewhat like that of a cardiac
pacemaker. The stimulator is then implanted beneath the skin under the
collarbone. The patient can switch on the stimulator with a hand-held
control, sending electronic pulses to the brain to interrupt the signals
that cause tremor. Research indicates that DBS can also control other
symptoms, such as slow movement and rigidity, and complications such
as dyskinesia.
View this surgery: High Quality - Low Quality
Pallidotomy and thalamotomy are surgical procedures that have been available
for several years. The patient remains awake (but anesthetized) while
the surgeon makes a permanent lesion in specific parts of the brain.
The lesion interrupts signals that cause tremor and other symptoms.
Rehabilitation Therapy
Physical, occupational, or speech therapy combined with modifications
in the home environment can help individuals with Parkinson's achieve
maximum comfort, safety and independence.
Sections of this information were reprinted and adapted, with
permission, from the National Parkinson Foundation, Inc. web site.
For additional information and resources about Parkinson's Disease,
visit the National Parkinson Foundation web site at www.parkinson.org
