Parkinsons Disease
PARKINSON’S DISEASE AND TREMORS
Parkinson’s Disease is a disease of that part of the brain controlling aspects of movement pertaining to maintenance of muscle tone balance, coordination of opposing muscle groups, and the smooth transition from the resting state to movement. These seemingly unrelated aspects of muscle control are what enable a normal person to move in a fluid and gradual manner, without unnecessary jerking motions as complex groups of muscles go into action. In addition, it allows us to use certain muscle groups while allowing others to stay relaxed. The part of the brain in question is called the basal ganglia.
In Parkinson’s Disease, the basal ganglia begin to degenerate progressively for unknown reasons. The functional defect seems to include a deficiency of the chemical called dopamine in this area, and other chemical disturbances are suspected as well. It has been postulated that this damage may result from some unknown toxic element or as the result of a previous viral infection. Familial factors do not seem to play a major role. It is not a contagious disease, and generally affects older people.
Any or all of the findings of Parkinsonism may be caused by specific drugs (especially the major tranquilizers such as Thorazine and Haldol), and following encephalitis or other forms of brain injury. The discussion below refers to the standard syndrome of essentially unknown cause.
Symptoms
Although symptoms may occur in the fourth and fifth decade in as many as 15% of cases, they usually come on in the late middle years or in old age, in a gradual manner. One side of the body may be affected initially, but both sides generally become involved as time goes on. The patient may develop difficulty in initiating walking or other movement, and such movements may be very slow and deliberate. Resting muscle tone may increase, such that a rigid appearance develops. This interferes with such spontaneous phenomena as facial expression, and a so-called “mask-like” face is common. The arms may fail to swing naturally during walking. A shuffling gait with a tendency to turn the whole body instead of just the head may occur.
The characteristic tremor (not present in all patients) is the most obvious symptom, but often is less disabling than the above problems. It is usually in the resting state and involves the hands in a 4 or 5 per second “pill rolling” motion of the thumb and index finger. The head, lips, and other parts may be involved. Interestingly, the tremor may briefly abate during other purposeful motions.
Dementia, seborrhea of the skin, and difficulty with wide blood pressure fluctuations are present in some patients, and the endstage disease may involve all of the above symptoms, leaving the patient a total invalid.
Treatment
The drug levodopa (l-dopa) has revolutionized the treatment of Parkinson’s Disease, although not without a price in terms of side effects. Often given with a second ingredient called carbidopa which reduces some of the side-effects, the combination drug is called Sinemet. The drug is administered in very careful dosages which may require frequent adjustments. It must be given anywhere from hourly to three times daily, depending on the individual’s response. Digestive upset and hemorrhage, cardiac rhythm disturbances, confusion, depression, and even psychosis and delirium are among its adverse effects in some patients, and often are dose-related. Some patients develop, ironically, bizarre facial or other movement disorders which may be quite grotesque.
Despite the potential for side-effects, l-dopa can provide dramatic benefit for some patients who had been virtually crippled by their disease, and under careful management the drug can usually be successfully controlled and quite tolerable. The affects may unexplainably disappear at periods in a sort of “onoff”
phenomenon; truly it is a poorly understood drug. Nonetheless, the suffering from severe parkinsonism warrants its use in many patients.
Alternative drugs which are of less benefit and less toxicity are sometimes useful in milder cases. These include bromocriptine, trihexyphenidyl, amantadine, and others. They can be used alone, with l-dopa, or as a diagnostic trial when the diagnosis is in question, but rarely provide significant longterm
benefit.
Prognosis
Parkinson’s Disease is progressive, although the rate of progression is variable from patient to patient. Even with optimal treatment, disability may still occur within 5 to 10 years, though current therapies may help significantly. Life expectancy is reduced by this disease, although the more optimistic recent estimates place it within six months of normal life expectancy. Exact figures are difficult to specify, but clearly the quality of life for these patients has been markedly improved with modern treatments.
An excellent source of further information on Parkinson’s Disease is the United Parkinson Foundation, 360 West Superior Street, Chicago, Illinois (312) 664-2344.
ESSENTIAL TREMOR
Quite a common condition, essential tremor is a poorly understood disorder of movement which causes the early onset (often in childhood) of a rhythmic shaking of the hands and head, sometimes involving the vocal cords. It is usually most prominent during purposeful activity or maintenance of a nonresting position. Often, it is relieved temporarily by alcohol. If it is familial, the term familial tremor is used.
Diagnosis is generally by history and careful examination. A skilled physician can usually exclude, at least tentatively, Parkinson’s Disease by the absence of other signs of that disease. Tumors of the brain, especially the cerebellum, must also be ruled out sometimes with a CAT scan. Any tremor warrants careful medical evaluation prior to assuming it is “essential.”
It has been found that the drugs such as propranolol and primidone are quite effective in the treatment of this symptom, when it impairs the patient’s quality of life. Alcohol is effective but when evaluated as a drug for regular long-term use, it is regrettably toxic.
Essential tremor tends to progress only very slowly, and seems to plateau in many patients. With adequate drug management, most patients can manage quite nicely, unless their work involves frequent precise hand or voice control. In that event, more intensive drug drug therapy or even a career re-evaluation may be necessary. Life expectancy is apparently completely normal. 1/89