A genetic form of Parkinson disease which involves progressive degeneration of the central nervous system.
* Movement disorder * Muscle rigidity * Tremor * Altered mood * Altered behavior * Altered sensations * Slowed movements * Impaired balance * Fatigue * Speech problems * Swallowing difficulty
Although the cause of Parkinson’s disease is unknown, study of the extrapyramidal brain nuclei (corpus striatum, globus pallidus, and substantia nigra) has established that a dopamine deficiency prevents affected brain cells from performing their normal inhibitory function within the central nervous system. Parkinson’s disease occurs in families in some cases; in others, it’s secondary to external factors such as medications used to treat schizophrenia. Parkinson’s disease, also called parkinsonism, paralysis agitans, and shaking palsy, is one of the most common crippling diseases in the United States. Parkinson’s disease strikes 2 in every 1,000 people, most often developing in those older than age 50; however, it also occurs in children and young adults. Because of increased longevity, this amounts to roughly 60,000 new cases diagnosed annually in the United States alone. Incidence increases in persons with repeated brain injury, including professional athletes, and persons using psychoactive substances, whether prescribed or illicit.
Because Parkinson’s disease has no cure, the primary aim of treatment is to relieve symptoms and keep the patient functional as long as possible. Treatment consists of drugs, physical therapy and, in severe disease states unresponsive to drugs, stereotactic neurosurgery or the controversial treatment called fetal cell transplantation. In this treatment, fetal brain tissue is injected into the patient’s brain. If the injected cells grow within the recipient’s brain, they will allow the brain to process dopamine, thereby either halting or reversing disease progression. Neurotransplantation techniques, including the use of nerve cells from other parts of the patient’s body, have been attempted with varying results. Drug therapy usually includes levodopa, a dopamine replacement that’s most effective during early stages. It’s given in increasing doses until symptoms are relieved or adverse effects appear. Because adverse effects can be serious, levodopa is frequently given in combination with carbidopa to halt peripheral dopamine synthesis. Occasionally, levodopa proves ineffective, producing dangerous adverse effects that include postural hypotension, hallucinations, and increased libido leading to inappropriate sexual behavior. In that case, alternative drug therapy includes anticholinergics such as trihexyphenidyl, antihistamines such as diphenhydramine, and amantadine, an antiviral agent. Research on the oxidative stress theory has caused a controversy in drug therapy for Parkinson’s disease. Traditionally, levodopa-carbidopa has been a first-line drug in management; however, it has also been associated with an acceleration of disease process. Inclusion of entacapone potentiates the effects of levodopa-carbidopa treatment so that less frequent doses are required. Selegiline, an enzyme-inhibiting agent, allows conservation of dopamine and enhances the therapeutic effect of levodopa. Selegiline used with tocopherols delays the time when the patient with Parkinson’s disease becomes disabled.