Parkinson’s disease (paralysis agitans) is a progressive neurological disorder of the brain. Nerve cells in the brain make chemicals called neurotransmitters. Neurotransmitters allow signals or messages to be sent from the brain to the body, or from the body back up to the brain. In Parkinson’s disease, the neurotransmitter Dopamine ceases to be produced because the brain cells responsible for producing dopamine progressively die. Dopamine is the neurotransmitter responsible for movement of skeletal and smooth muscles. Skeletal muscles allow movement of bones. Smooth muscles line the gastrointestinal tract and allows food to be swallowed, and then to move through the stomach and intestines by waves of contractions. Skeletal muscles are voluntary which means they can consciously be controlled. Smooth muscle is involuntary which means that there is no control as to how or when these muscles contract or move. Without Dopamine, there is no chemical signal to allow for movements of these muscles. Parkinson’s disease is the second leading degenerative brain disease in the United States, effecting more than 1.5 million people. Worldwide, there are seven to ten million people with Parkinson’s disease.
The causes of Parkinson’s disease are poorly understood at this time. Theories include physical aging of the body, exposure to environmental poisons, genetic predisposition, and brain injuries. However, actor Michael J Fox was diagnosed with this disease at a young age, which would discount the theory that Parkinson’s is caused by aging. Former boxer, Mohammed Ali, was diagnosed during his middle age with Parkinson’s disease which lends credence to the theory that head injuries could cause this disease. Ali took many blows to his head during his boxing career which could have caused brain injuries. Scientists are searching for abnormal genes on chromosomes which could mean that there is a genetic component to Parkinson’s disease. With the rapid advances in medical technology, and with stem cell research, there is hope for answers in the near future. Until science has these answers, there will be no cure of Parkinson’s disease. At present, there are new medications that can help alleviate some of the symptoms of Parkinson’s disease.
The prognosis, or outcome, of Parkinson’s disease is poor. However, the progression of this disease is slow and a person suffering from Parkinson’s can live many years with medical intervention. However, even with medications, this disease can adversely affect quality of life.
Physical symptoms of Parkinson’s Disease include problems with swallowing and constipation, stiffness and rigidity in skeletal muscles, slowness in muscle movements, tremors of one or both arms, impaired balance, and a fixed facial expression called “stone faced” because the facial muscles are very slow to contract allowing for smiling, frowning, and other facial expressions. Posture may become stooped and gait may become shuffled because lack of dopamine affects skeletal muscles responsible for posture and locomotion. There may be a marked change in vision and a decreased sense of smell. Emotionally, the patient may suffer from depression and anxiety. A neurologist makes the diagnosis based on subjective data provided by the patient, and his findings during the physical examination of the patient, such as muscle rigidity and decreased reflexes. There are no specific medical tests that can diagnose Parkinson’s disease.
Once the diagnosis of Parkinson’s disease is made, medications are begun to help alleviate symptoms. Patients have been traditionally treated with the medication Levadopa, also known as L-dopa which is converted to dopamine in the brain. Levadopa is often combined with carbidopa. Carbidopa works to improve the action of the levadopa. The names of these combined drugs are Sinemet and Atamet. Long term use of these medications, however, has adverse effects and can become ineffective.
The Federal Food and Drug Administration (FDA) recently approved a promising new drug named Azilect. In test subjects, this drug made dramatic improvements in the symptoms of Parkinson’s. Azilect improves tremors, rigidity, and slowness of movements. The patient is able to walk, talk, swallow, and dress themselves. However, as with any medication, there are adverse side effects in some patients. The side effects may include dry mouth, nausea, vomiting, upset stomach, constipation, headache, depression. Other symptoms include postural hypotension, hallucinations and moving with difficulty. There is a higher incidence of skin cancer. Azilect can also adversely react with other medications.
As with any medication, the physician must decide if the benefits of the drug outweigh the risks of the side effects.
Mirapex and Requip, are two recent drugs which mimic dopamine’s role in the brain, and both allow patients to regain some of their lost muscle control. Both are approved for use alone or with levodopa drugs. In clinical trials, patients taking Mirapex alone saw as much as a 30 percent improvement in symptoms.
Tasmar is a new drug called a COMT inhibitor. Researchers believe that Tasmar blocks a key enzyme responsible for breaking down levodopa before it reaches the brain. In trials, patients who took Tasmar experienced significant improvements in daily activities such as talking, writing, walking, and dressing.
The FDA has approved the drug Neupro (Rotigotine Transdermal System) for the treatment of the signs and symptoms of advanced stage idiopathic Parkinson’s disease (PD) and as a treatment for moderate-to-severe primary Restless Legs Syndrome (RLS). Neupro was previously approved by the FDA for the signs and symptoms of early stage idiopathic PD. Neupro is a dopamine agonist patch that provides continuous drug delivery for patients with PD and RLS.
Awaiting approval from the FDA is a new promising drug for Parkinson’s. It is a new dopamine agonist which means it is a drug that mimics the action of Dopamine in the brain. It is delivered through a delivery system that allows the blood levels of the drug to
remain constant. Studies suggest that not only does this drug help alleviatethe symptoms of Parkinson’s, but may also protect nerve cells from degeneration and cell death. There are also some other new drugs awaiting FDA approval.
With these new medications, Parkinson’s patients are offered hope in finding one drug that works for that individual in helping better control their symptoms so that they may live a better life with Parkinson’s disease. Hope is a just as powerful a tool as is medication in health care.
More information can be learned about Parkinson’s disease and available treatments through the National Parkinson Foundation, the Michael J Fox Foundation for Parkinson’s Research, the National Institute of Neurological Disorders and Strokes (NINDS), and the National Institute of Health (NIH).
