No one who watched Muhammad Ali struggle to carry the torch in the Atlanta Olympics can forget the devastation of Parkinson’s disease on this once mighty athlete. Those of us in nursing are all too familiar with its ravages. While it leaves mental functions relatively intact, it is devastating to the patients who lose their ability to dress or feed themselves or see their careers destroyed because they can no longer write or use a keyboard. It’s a disease without a cure, but the symptoms can be managed by medical and surgical therapies.
The British physician James Parkinson first described “the shaking palsy” in 1817. However, it wasn’t until the early 1960s that researchers identified the physiological defect that is the hallmark of the disease: the loss of certain dopamine-producing brain cells.1
Today, more than half a million people in the United States have Parkinson’s, with about 50,000 new cases diagnosed each year. It strikes slightly more males than females, and whites are more likely to develop it than blacks or Asian-Americans.1,2 It’s a disease of late middle age, with average age of onset of 60 years. The incidence in the general population is 100 per 100,000, but 1,000 to 2,000 per 100,000 for those over 65.2 For unknown reasons, physicians are reporting more cases of “early onset” Parkinson’s the past few years, with an estimated 5 to 10 percent of patients being under 40 years old at first diagnosis.1
This article will discuss the causes and symptoms of Parkinson’s, as well as medical and surgical treatments. Genetic research offers promising possibilities; recently, a genetic abnormality has been linked to certain cases. The first new surgical approach in 30 years was approved last August by the Food and Drug Administration (FDA) for the tremor of Parkinson’s.3 Investigation continues into ways to relieve the other symptoms as well.
Parkinson’s disease is caused by the progressive destruction of neurons in the region of the brain that produces the neurotransmitter dopamine, leading to a dopamine deficiency. Dopamine helps transmit impulses that coordinate movement. Neurochemical changes other than dopamine depletion create deficits of neurotransmitters, resulting in loss of communication among the brain cells that coordinate and control movement, balance, and walking.2
A genetic abnormality may be responsible for Parkinson’s cases with early onset of symptoms, the National Human Genome Research Institute at the National Institutes of Health announced in June 1997. Mutations in a protein called alpha synuclein caused by an anomalous gene are linked with some of the motor dysfunctions of the disease. Surprisingly, the amyloid plaques (damaging starchlike proteins deposited in tissues) of patients with Alzheimer’s disease also contain fragments of the protein, suggesting a similar mechanism may be operating in these diseases.4
There is evidence that free radicals (atoms or molecules with an unpaired electron) play a role in the development and progression of Parkinson’s. The free radicals seize electrons from molecules with which they come into contact, causing cell damage. Protective enzymes and vitamins C and E may inhibit formation of the damaging free radicals.2
Other possible causes include viruses (postencephalitic Parkinson’s); environmental toxins (pesticides, manganese, carbon disulfide, and carbon monoxide poisoning); and certain medications, such as neuroleptics (antipsychotics and antidepressants), older antihypertensive drugs such as reserpine and methyldopa (Aldomet), and metoclopromide (Reglan). Drug-induced Parkinson’s is usually reversible, once the causative agent has been eliminated.2,5 Cerebrospinal fluid from people with Parkinson’s has been reported to be toxic to dopamine-producing neurons growing in cultures, so there is a possibility that a toxin may be present in those with the disease.2
There are no imaging studies for Parkinson’s, nor laboratory tests. Instead, the diagnosis is made by carefully observing symptoms and ruling out other diseases. In some instances, the patient’s response to levodopa (the standard medication for Parkinson’s) is so impressive that a presumptive diagnosis can be made. In fact, if a patient fails to respond to levodopa, the diagnosis of Parkinson’s should be questioned.6 A biopsy of the brain of a deceased patient with Parkinson’s shows characteristic deposits called Lewy bodies inside the cells. These deposits are considered a marker for Parkinson’s, but are not useful for making the diagnosis in a living patient.2 Parkinson’s is often misdiagnosed because it may be confused with essential tremor, also a disease of the elderly, but one that rarely results in serious disability. In its mildest forms, Parkinson’s may be accepted by the patient and physician as a normal consequence of aging not requiring special attention.6
The four primary symptoms of Parkinson’s are tremor, rigidity, bradykinesia, and postural abnormalities. Additional secondary symptoms are usually present, and the combination of symptoms varies widely among individuals. (See “Secondary Symptoms of Parkinson’s Disease.”) Details about the primary symptoms follow.
- Tremor: The Parkinson’s tremor typically begins in a hand, with a rhythmic back and forth motion of the thumb and finger, referred to as “pill rolling,” occurring three times per second. It is most obvious when the arm is at rest or during stressful periods. It affects only one side of the body in 75 percent of patients, disappears during sleep, and improves with intentional movement.
- Rigidity: Nearly all patients suffer rigidity as the result of the constant contraction and tension of opposing muscle groups. The rigidity may cause chronic aching. When another person tries to move the affected limb, it displays the jerky, ratchetlike movement known as “cogwheel” rigidity.
- Bradykinesia: Bradykinesia refers to the slowing down of movement and the impaired ability to initiate a movement or modify it once begun. Spontaneous and automatic movements are both affected. The patient may take several hours to do the movements of washing, dressing, and eating. This is the most distressing symptom to many patients.
- Postural instability: The postural abnormalities may be the last symptoms to develop. The patient has impaired balance and coordination, and may lean backward or forward when walking. Some walk with a series of tiny, fast steps called “festination.” The combination of movement disorders can cause a patient to “freeze” in mid-stride or to topple over if bumped.
Amantadine (Symmetrel), initially introduced as an antiviral agent, was found to help patients with Parkinson’s. Although the mechanism of action is unclear, it improves most of the symptoms by causing the release of increased amounts of dopamine in the brain.7 It can be used as a first-line medication for those with mild Parkinson’s. Amantadine becomes less effective over weeks or months in some patients. The usual dosage is 200 to 300 mg daily.2,5,7
For some patients, anticholinergic drugs have proven effective. These medications (which relax smooth muscles, increase heart rate, and decrease gastric and oral secretions) block some of the effects of acetylcholine in the brain of the Parkinson’s patient. (Acetylcholine contributes to tremors and rigidity in the Parkinson’s patient.) Trihexyphenidyl (Artane)can be used to decrease rigidity but has little effect on tremors. Benztropine (Cogentin) can reduce tremors and rigidity, resulting in improved mobility.2,5 Antihistamines are sometimes used because of their mild anticholinergic effect.7
Levodopa has been the standard treatment for Parkinson’s since its introduction in the 1960s. While not a cure, it can delay the onset of the most disabling symptoms for a time, and about 75 percent of patients can live fairly normal lives.1 Levodopa is the precursor to dopamine; it crosses the blood-brain barrier and in the brain is converted into dopamine—the neurotransmitter in short supply for Parkinson’s patients.
Levodopa is most often given in combination with the drug carbidopa, which delays the conversion of the levodopa into dopamine until it reaches the brain. Adding carbidopa to the levodopa also reduces the amount of levodopa needed. Sinemet is the only combination drug (carbidopa and levodopa) approved for use in the United States. Recently, a controlled-release preparation of Sinemet has been introduced allowing less frequent dosing and fewer adverse effects—always desirable from a patient’s point of view. A generic equivalent is also now available.2
A ratio of one part carbidopa to four parts levodopa is used. The medication is referred to as CD/LD, and the separate amounts of carbidopa and levodopa are always stated. The initial dosage depends on the age and frailty of the individual. A common starting dose is 25/100, three times a day (25 mg carbidopa and 100 mg levodopa).2,5,7 There is no “right” dose of CD/LD; it is meticulously titrated to the patient’s response and side effects, with the goal being the lowest possible dosage necessary to achieve acceptable results. Levodopa can be extremely effective early in treatment, but it becomes less effective over several years. Higher doses may be required, but they lead to worsening side effects. As time goes on, the patient may suffer disabling end-of-dose symptoms; i.e., as the dose tapers off, the patient may freeze up or “turn off.”
Side effects include nausea, vomiting, hypotension, and cardiac arrhythmia. Dyskinesias (movement disorders) can take nearly any form and may include involuntary twitching of limb and facial muscles, tremor, tics, and athetosis, the snakelike writhing of the upper extremities.2,5,7 There is also potential for serious behavioral changes, such as hallucinations, delusions, and paranoia. Levodopa should not be taken at all by some patients, for example, those with glaucoma, melanoma, hypertension, or heart disease and those taking certain drugs for psychosis.5
The dopamine agonists are medications directly opposing dopamine’s actions. They include bromocriptine (Parlodel) and pergolide mesylate (Permax) and are sometimes used alone early in the course of Parkinson’s, or later in the illness in conjunction with CD/LD. The exact mechanism of action is unclear, but it’s likely they stimulate different dopamine receptors than does levodopa. Selegiline (Eldepryl) inhibits the metabolic breakdown of levodopa, but it’s not a dopamine agonist The side effects of these three medications are similar to those of levodopa.1,2,5
In July 1997, the FDA approved the first new medication for Parkinson’s this decade. Pramipexole dihydrochloride (Mirapex) is also a dopamine agonist, but is more specific for certain dopamine receptor sites. It can be used alone early in the course of the disease or later in conjunction with CD/LD. When given in combination, it allows the dosage of levodopa to be decreased. Patients on pramipexole have improved by up to 20 percent, and it seems most effective for the sickest patients.8
Nursing and therapy interventions
A nurse working with a Parkinson’s patient needs to develop a nursing care plan to address these common problems:9
- impaired physical mobility due to tremor, rigidity, and bradykinesia;
- altered nutritional status due to motor difficulties with chewing and swallowing;
- impaired verbal communication due to decreased speech volume and facial muscle movement;
- ineffective coping mechanisms related to loss of independence; and
- constipation related to decreased mobility.
Physical therapy to maintain muscle tone and range of motion, and gait and transfer training can help patients maintain function as long as possible. Occupational therapy helps maintain activities of daily living and teaches safety skills. Assistive devices such as canes, walkers, grab bars, raised toilet seats, and special table cutlery make life easier. Speech therapy can teach the patient how to maximize a weakened voice, manage troublesome secretions, and strengthen facial muscles.9,10 Education of the patient, family members, and caregivers is important for management of Parkinson’s.
Surgery offers only partial relief of Parkinson’s symptoms, and at some risk to the patient. It does not prevent progression, nor alleviate the hypokinetic symptoms. Neurosurgical procedures destroy parts of the brain that help control movement in a normal individual, but which contribute to movement disorders in the patient with Parkinson’s. A thalamotomy (surgical destruction of part of the thalmus) helps the tremor but not other symptoms. A pallidotomy, performed on the globus pallidus (part of the “motor communications center” of the brain), decreases rigidity and bradykinesia and, occasionally, partly relieves tremor. These surgeries are usually reserved for those who no longer respond satisfactorily to medical management.2 Results are transient, lasting up to two years.
Over the past few years, transplantation of fetal brain tissue into the brain has benefited some patients through regeneration of damaged nerve cells. This controversial procedure is undergoing controlled clinical trials at three institutions under a research grant awarded by the National Institute of Neurological Disorders and Stroke.1
Advocacy groups, such as the American Parkinson Disease Association and the National Parkinson Foundation, have been unanimous in their support of a brain implant approved last August by the FDA. The device is similar to a cardiac pacemaker. There are two external components—the patient’s hand-held magnet and a programming device—and three internal components—the pulse generator, the lead, and the extension.11
The pulse generator containing a battery and microelectric circuitry is surgically implanted under the skin near the clavicle. It is about 2 inches square and weighs less than 2 ounces. The lead has four electrodes at its tip, which are implanted into the thalamus. A hole is drilled through the skull for access. The extension is the wire passing under the skin of the neck, connecting the generator to the lead.
The device is placed by a neurosurgeon during a five-hour procedure, using a stereotactic head frame and imaging techniques (MRI or CT scan). The patient is awake so the surgeon can test tremor suppression to ensure the electrodes are placed in the right spot. The electrical pulses block the malfunctioning brain signals causing the tremors.11
The implant is currently approved for use in only one side of the brain. This will help many patients because trembling is most often unilateral. The patient can change the settings and turn the device on and off with the magnet. Tremors cease during sleep, and patients can turn the device off at bedtime, thus conserving the battery. The battery can last five years and is easily replaced under local anesthesia in an outpatient clinic. Unlike the thalamotomy and pallidotomy, the implant is reversible, should newer treatment options develop. Also, there is no evidence that the effectiveness of the implant lessens over time.
Some medical journals cite favorable results with the implant. One reported mean reductions of more than 2 points on a 4-point tremor rating scale.12 Another found 92 percent of patients had complete disappearance of tremors, and 7 percent had moderate or slight improvement.13 Side effects include mild numbness and tingling, mild weakness in the upper extremities, some difficulty forming speech, and sometimes a loss of balance. These are related to the intensity of the impulse and respond to a programmed decrease or temporary cessation of the impulses.11 Disadvantages are a risk of infection, the need for periodic replacement of the battery or leads that might malfunction, and the price tag of $25,000 for the surgery and the device. The cost may seem high, but compared to the estimated $5.6 billion spent annually on Parkinson’s patients, it may not be out of line.1 This particular implant controls only tremor. In Europe, electrical stimulation of different parts of the brain is under investigation, and the work shows great promise in alleviating the other symptoms—the bradykinesia, rigidity, and postural instability.
More help for those with Parkinson’s is on the way. A group called Independence Dogs Inc. provides dogs to patients; the dog helps prevent falls, and by pawing the foot of a patient “frozen” in midstride, it restarts the movement. Research on the cause of Parkinson’s continues as does testing of experimental treatments. Human genome research shows the potential for gene therapy. The new implant and the promise of others to come offer hope to many patients.
- National Institute of Neurological Disorders and Stroke. (1997).
- Rakel, R.E. (Ed.). (1997). Conn’s Current Therapy. Philadelphia: Saunders Co., 963-972.
- National Parkinson Foundation Inc. (1997).
- National Institutes of Health. (1997).
- Aminoff, M.J. (1997). “Nervous System.” In Current Medical Diagnosis & Treatment—1997—A Lange Medical Book. Stamford, Conn.: Appleton & Lange, Publishers, 919-921.
- Massachusetts General Hospital, Harvard University’s Parkinson’s Web. (1997).
- Spratto, G. R., & Woods, A.L. (1997). Delmar’s Therapeutic Class Drug Guide. New York: Delmar Publishers, 223-225, 775-785, 927-937.
- Rennie, D. (Deputy Ed.) (1997). “Safety and efficacy of pramipexole in early Parkinson’s disease.” Journal of the American Medical Association, 278(2), 125-130.
- The Lippincott Manual of Nursing Practice, 6th Ed. (1997). Philadelphia: Lippincott, 386-387.
- Mosby’s Medical Encyclopedia. (1997) “Parkinson’s Disease.” [CD ROM.]
- Medtronic Inc. (September 1997). Corporate communications press kit. Medtronic Inc.: Minneapolis, Minn.
- Hubble, J.P., et al. (1997). “Effects of thalamic deep brain stimulation based on tremor type and diagnosis.” Movement Disorders, 12(3), 337-341.
- Benabid, A.L., et al. (1996). “Chronic electrical stimulation of the ventralis intermedius nucleus of the thalamus as a treatment of movement disorders.” Journal of Neurosurgery, 84(2), 203-214.