Parkinson's disease is a progressive neurological disorder which produces
degeneration of cells in deep structures of the brain that control involuntary
movement and muscle tone. Primary symptoms imclude resting tremor (shaking),
bradykinesia (slowness), rigidity (stiffness), and postural instability
(imbalance). Muscle power is not affected. Diagnosis is based on clinical
examination, for there are no definite x-ray or laboratory abnormalities.
If a patient has two of the four primary symptoms, and no other explanation is
found, a positive diagnosis is made.
Parkinson's disease is associated with depletion of a chemical transmitter in
the brain called "dopamine." This produces a relative excess of a competing
transmitter called "acetylcholine." Therapy includes medications which attempt
to restore ths balance by increasing dopamine or decreasing acetylcholine.
Parkinson's disease is estimated to affect over 1 million Americans, with
50,000 new cases occuring each year. A definite cause has not been found.
Infectious, toxic and genetic factors have been investigated, but no definite
relationship has been detected. "Parkinsonism" may follow stroke, encephalitis,
carbon monoxide poisoning or medication exposure; but "Parkinson's disease"
has no known etiology.
The most effective treatment for Parkinson's disease is Sinemet. Sinemet
consists of two chemicals: "L-Dopa," which is converted in the brain into
dopamine; and "Carbidopa," which prevents metabolism of L-Dopa in the body
before it reaches the brain. Five strengths of Sinemet are available:
10/100, 25/100, 25/250, 50,200 (CR), and 25/100 (CR). The top number refers
to the mg. amount of Carbidopa, and the bottom number refers to the mg. amount
of L-Dopa in each pill. The 50/20 (CR) and 25/100 (CR) are the newest Sinemet
products, and are longer lasting (Controlled Release) than the other forms.
When to begin Sinemet for each patient is controversial because problems occur
with prolonged use.
Dopamine agonists stimulate the same receptors in the brain as dopamine.
They do not require nerve transmission to work and therefore are helpful when
Sinemet is losing its effectiveness. They may also be the drug of first choice
for some Parkinson patients, particularly young-onset patients. Currently
available agonists include "Parlodel," "Permax," "Mirapex," and "Requip."
Eldepryl slows the metabolism of dopamine by inhibiting an enzyme called
"MAO." It thereby prolongs the duration of Sinemet effect.
Tasmar also prolongs the benefit of Sinemet by inhibiting an enzyme
called "COMT." Both Eldepryl and Tasmar may increase Sinemet side effects.
Three cases of death from liver failure in patients taking Tasmar have been
documented. Liver function blood tests every two weeks are mandatory.
Anticholinergics are older medications developed before the discovery of
Sinemet. They work by blocking the effects of relatively excessive acetycholine.
Examples include "Artane," "Cogentin," and "Kemadrin." They may be useful for
tremor in some patients, but are less popular now because of frequent side
effects.
Symmetrel has value in some patients, but is considered only a mild
supplemental drug at this time.
Other important treatment modalities include frequent exercise, good
nutrition, and, in severly affected patients, rehabilitation efforts (physical,
occupational, and speech therapy).
Neurosurgery was a common treatment for Parkinson's disease until the
introduction of levadopa in the late 1960's. With the loss of efficacy and
complications of medical therapies, there has been a recent renewed interest
in surgical treatments. The most common procedures involve a destructive lesion
or simulation of basal ganglia structures deep in the brain. Thalamotomy
and thalamic stimulation are used for intractable tremor. Pallidotomy,
pallidal stimulation, and subthalamic stimulation have been used in
patients with motor fluctuations or dyskinesias. Embryonic tissue transplants
are available on an experimental basis.
Unfortunately, Parkinson patients have many problems despite advances in medical
care.
On/Off Effect (Phenomenon) occurs in advanced states and produces dramatic,
often sudden, fluctuations in Parkinson symptoms. It, in part, represents erratic
absorption and shortened duration of action of Sinemet medication. Patients may
require their medication at very frequent intervals. It is crucial that the
hospitalized patient receive his medication in the same dosage and schedule as at
home. Stopping Sinemet may induce "Neuroleptic malignant syndrome," a potentially
fatal disorder.
Dyskinesias or Dystonia are involuntary abnormal movements and
muscle spasms that tend to begin in patients who have been on Sinemet for a long
time. These symptoms occur, however, when the dopamine level is high in the brain.
More frequent dosage schedules with smaller total dosage may be helpful in lessening
these problems.
Depression is a common feature of this illness which needs to be treated
specifically.
Confusion occurs frequently in later stages of this disorder. It may occur
because of frequently associated dementia, because of medication effect, or a
combination of both. The anticholinergics, dopamine agonists, and Eldepryl are the
most likely medication offenders. Lowering dosage to lessen confusion, unfortunately,
often sacrifices mobility.
Falling, also, is usually late manifestation of the disease process, but a very
severe one. Low blood pressure, associated with advanced disease and medication
effect, contributes to the problem. Fractures and other injuries can necessitate
hospitalization and shorten life expectancy. Walkers, canes, and gait training may
lessen this risk, but wheelchairs may be necessary for some patients.
Constipation occurs in most patients because of decreased bowel motility
and medication effect. Adequate water consumption, stool softeners, bulking
agents and foods, and routine bowel habits may help. Laxatives and enemas are
useful in crisis situations, but chronic usage may aggravate the problem.
Urinary retention is a particular problem in male patients using
anticholinergic medication.
Sleep disturbance is another significant problem in Parkinson patients.
Insomnia is not only intolerable to the caregiver at night, but also affects
the patient's wellbeing during daytime. Abnormalities in neurotransmitters,
depression, and medications are contributing factors, as well as stiffness and
general discomfort. Daytime exercise, good sleep habits, nocturnal massage
for stiffness may help. The use of antihistamines, antidepressants or
minor tranquilizers may be necessary, as well as adjustment of Parkinson
medication.
Nutritional deficiency is another serious common problem in the Parkinson
patient. Difficulty swallowing, increased metabolic rate, and depression are
contributing factors. Vitamin and caloric supplements may be necessary,
as well as advice from a speech and swallowing expert.
Finally, the hospitalized Parkinson patient, because of slowness and stiffness,
is at increased risk for hospital-acquired complications. Pneumonia,
aspiration, urinary tract infection, deep vein thrombophleblitis, and
decubitus ulcers are particular concerns. Mobilization, careful feeding,
DVT prophylaxis, and attention to skin may be life saving. The nurse who
meets the challenges of the Parkinson patient will learn skills for all
others as well.
