Parkinson's Disease

Introduction

Thanks to outspoken celebrities such as Muhammad Ali and Michael J. Fox, Parkinson's disease has gained widespread attention in recent years. Both men have Parkinson's disease, and both have focused their efforts and used their celebrity status to raise funds for research and increase awareness about the degenerative nerve condition.

What is it?

Parkinson's disease is a non-fatal, chronic neurological condition named after Dr. James Parkinson, who first identified and described the syndrome in 1817. The disease progresses slowly, affecting a small area of cells in the mid-brain known as the substantia nigra. Degeneration of these cells causes a reduction in the chemical called dopamine, and this reduction results in the signs and symptoms of Parkinson's disease.

Although Parkinson?s disease can occur at any age, it rarely occurs in individuals younger than 30. Rather, it often occurs between the ages of 50 and 80 years, with most people experiencing their first symptoms around age 60. Typically, risk increases with age. Early symptoms are generally subtle and progress gradually. Although Parkinson's disease is a chronic illness, medication and the support of friends and family can help relieve many of the symptoms. This enables affected individuals to maintain a reasonable quality of life.

What causes it?

The cause of Parkinson's disease remains a mystery. The consensus among medical professionals is that it probably results from a combination of genetic and environmental factors. Idiopathic Parkinson's disease is caused by the gradual loss of neurons in the substantia nigra. The substantia nigra is the region of the brain that controls movement; particularly automatic movements such as arm swinging while walking. When nerve cells in this area become impaired and die, production of a chemical in the brain called dopamine, which aids in transmitting signals, decreases. The result is impaired movement.

Although Parkinson's disease is caused by degeneration limited to the substantia nigra, other degenerative diseases and some medications can produce secondary parkinsonism. Medications that can cause symptoms of Parkinson's disease include antipsychotics (mesoridazine [Serentil], thioridazine [Mellaril], chlorpromazine [Thorazine], perphenazine [Trilafon], fluphenazine [Prolixin], trifluoperazine [Stelazine], haloperidol [Haldol], thiothixene [Navane], risperidone [Risperdal]), antiemetics (prochlorperazine [Compazine]), gastrointestinal antimotility drugs (metoclopramide [Reglan]), and drugs that lower blood pressure such as reserpine (Serpasil). Drug-induced parkinsonism must be ruled out before the diagnosis of Parkinson's disease is made.

Who has it?

It has been estimated that as many as 1.5 million Americans are affected by Parkinson's disease, and about half of these individuals have not been diagnosed with the disease. At this time, it is impossible to predict who will get Parkinson's disease. Currently, there are no known preventive measures for Parkinson?s Disease.

What are the risk factors?

Currently, it is impossible to predict who will get Parkinson's disease, and there is no known method for preventing its occurrence. The disease is believed to affect both men and women almost equally. Currently, age is one of the main risk factors for the disease. Most of those affected do not experience symptoms until after age 50. However, 5-10% of patients have a subset of Parkinson's disease known as young-onset Parkinson's disease, which affects those under age 40. Two gene mutations have been identified in patients with this type of Parkinson?s Disease. Although the condition is clinically the same, treatment options may differ.

As mentioned previously, the disease is thought to result from a combination of genetic and environmental factors. Exposure to pesticides and other toxins has been suspected as a potential risk factor, but this has not yet been proven as a causative factor. In fact, many Parkinson?s patients have never been in contact with these products.

It is unclear whether the disease is an inherited problem. 5-10% of Parkinson?s disease patients have members of their family with the same condition, but no single gene has been found that is mutated in all patients with Parkinson?s disease. In studies of identical twins, it appears that there is a genetic link for young-onset Parkinson?s disease, but not for Parkinson?s disease that affects those over 60 years.

What are the symptoms?

Symptoms of Parkinson's disease appear when the amount of dopamine in the brain is decreased. They often appear gradually, yet with increasing severity. Because the initial symptoms are similar to those of other neurological conditions, diagnosis can be difficult.

Some individuals have few symptoms, whereas others suffer more severe, debilitating symptoms. Common symptoms include the following:

  • Resting tremor on one side of the body
  • Stiffness of the limbs (often referred to as rigidity)
  • Generalized slowing of movements (known as bradykinesia) and gait
  • Gait or balance problems
  • Small, overcrowded handwriting (called micrographia)
  • Lack of arm swing on the affected side of the body
  • Less frequent blinking and swallowing
  • Increased dandruff
  • Increased oily skin
  • Depression
  • Anxiety
  • Decreased facial expression
  • Episodes of feeling "stuck in place" when initiating a step (called freezing)
  • Lowered voice volume
  • Foot dragging on the affected side
  • Changes in posture
  • Feeling more tired
  • Weight loss

How is it treated?

Currently, there is no cure for Parkinson's disease. The goals of treatment are to minimize disability, reduce the possible side effects of drug therapy, and help the patient maintain the highest possible quality of life.

Mild symptoms that do not interfere with daily activities or disrupt work duties may not require medication. When prescription drugs are needed, they help to manage symptoms, but they cannot stop the disease from progressing. Often, when a drug no longer effectively controls symptoms, another drug may be added to existing therapy. Optimal management is highly individualized and is best determined by a doctor who specializes in the treatment of Parkinson's disease.

Medications currently used in Parkinson?s disease include levodopa, COMT inhibitors, dopamine agonists, amantadine, anticholinergics, and selegiline. Levodopa (Larodopa) is a common medication used in Parkinson?s disease that is converted to dopamine in the brain. Dopamine is used to transmit signals in the brain and allows for normal movements. Levodopa is often combined with carbidopa (Sinemet) which increases the amount of levodopa that goes to the brain.

COMT inhibitors include entacapone (Comtan) and tolcapone (Tasmar) and work by blocking the action of an enzyme in the body known as catechol-O-methyltransferase that breaks down dopamine. By inhibiting dopamine?s breakdown, COMT inhibitors are able to decrease the symptoms of Parkinson?s disease that result from decreased levels of dopamine.

Dopamine agonists such as bromocriptine (Parlodel), pramipexole (Mirapex), ropinirole (Requip), and apomorphine (Apokyn) act like dopamine within the brain to reduce Parkinson?s disease symptoms.

Amantadine (Symmetrel) is an antiviral medication that was found to have benefit in Parkinson?s disease, although the mechanism is unknown. It is thought that amantadine may work by increasing the response of the brain to dopamine or releasing stored dopamine.

Anticholinergics used to treat Parkinson?s disease include benztropine mesylate (Cogentin), procyclidine (Kemadrin), biperiden (Akineton), and trihexyphenidyl. These drugs work by exerting a relaxing effect on the body.

Selegiline (Zalapar, Eldepryl, Emsam) is another option for patients suffering from Parkinson?s disease; however, its mechanism of action is unknown. Selegiline appears to inhibit the breakdown of dopamine, and is usually added to a patient?s therapy when the effectiveness of levodopa is decreased. Emsam is available as a patch, and Zelapar is available as disintegrating tablets.

Surgery remains the only option for those patients with severe or quickly-progressing Parkinson's disease who have failed all other therapies. In a surgical technique called pallidotomy, an electric probe is used to destroy a small, overactive portion of the brain that is thought to cause the symptoms of Parkinson's disease.

A thalamotomy is the removal of the thalamus region of the brain. The thalamus is responsible for involuntary movements; destroying it prevents involuntary movements. Although this type of surgery is rarely performed, it can be a last resort for patients who have disabling tremors in the hand or arm. However, the procedure does not relieve other symptoms of Parkinson's disease. .

Thalamic stimulation is another approach in the management of Parkinson's disease. In this procedure, an electrode wire is inserted into the thalamus. The other end of the wire is connected to a pulse generator, and the generator is placed under the skin in the chest area. This device can produce the benefit of thalamotomy without causing a wound or scars on the skin. Thalamic stimulation has shown to be very effective in the management of tremor in Parkinson's disease.

Deep brain stimulation (DBS) is a new, alternative procedure used to destroy small regions of the brain. A thin electrode implanted into the brain blocks brain waves that can cause uncontrollable movements. This procedure must be continued throughout the patient?s life. It is especially useful in patients that have severe symptoms associated with tremor, involuntary movements (dyskinesia), and problems with gait.

Helping Yourself

Parkinson's disease can have a huge impact on an individual's daily activities and overall lifestyle. Learning coping strategies, preventing falls, getting proper nutrition, participating in regular movement and exercise, getting proper amounts of sleep, and ensuring adequate hydration can help those suffering from Parkinson's disease maintain a high quality of life.

Coping With Parkinson's Disease

  • Maintain a positive attitude in both occupational and social situations.
  • Keep friends and co-workers informed of your status and to help maintain your independence, accept help only when needed.
  • Perform tasks on a priority basis to achieve a sense of accomplishment and purpose.
  • Join local Parkinson's disease organizations and support groups.

Fall Prevention

  • Avoid carrying objects in both hands while walking, which can disrupt balance.
  • Avoid standing for long periods with your feet too close together, which can increase your risk of falls.
  • Lift your feet when walking. Falls may result when you shuffle or drag your feet: a common feature among people with Parkinson's disease.
  • Swing your arms when walking. This helps maintain balance and decreases fatigue.
  • If your feet feel "frozen to the floor" when you start to walk or move, you can (1) attempt to step over an actual or imaginary obstacle in your path or (2) rock from side to side.
  • If balancing is difficult, you can learn to use a single-point cane with a large, rubber tip. It takes practice to use a cane comfortably, but once mastered, this skill can make it much easier for you to maintain your balance.
  • Do not wear rubber-soled shoes because they grip the floor and may cause you to trip.
  • If rising from a seated position is difficult, place your feet directly under your knees and stand up firmly to overcome the pull of gravity. Rather than using your hands and arms when attempting to stand up, use your thigh muscles. This exercise is also beneficial in strengthening the large muscles of the legs, which helps maintain strength and promotes continued ambulation.
  • If you tend to feel lightheaded, move slowly when changing positions. When getting out of bed, sit up slowly, remain seated on the side of the bed for 15 to 30 seconds, and then stand in one place for 15 to 30 seconds before walking. This technique can prevent falls.
  • Do not use throw rugs or wax the floors of your home. Ensure that rooms are well lit, and consider using night-lights in hallways and bathrooms. Keep your home free of clutter to prevent tripping.
  • In the bathroom, you may need to use grab bars to get into and out of the bathtub. A raised toilet seat with arm rails may also be a necessity.
  • In the kitchen, you may need to use a long-handled sponge or mop to wipe up spills. Keep supplies that you use often in an easy-to-reach cabinet.

Nutritional Guidelines

  • Eat small, frequent meals rather than three large meals daily. This helps your body use food properly and makes it easier for you to maintain a healthy weight. Parkinson's disease can slow digestion and affect swallowing. If you have difficulty consuming solid foods, liquid supplements such as Ensure can help provide proper nutrition.
  • If you have no trouble digesting or swallowing food, eat foods that are high in fiber (vegetables, whole-grain bread, and cereals), and drink plenty of fluids to help prevent constipation and dehydration.
  • Sleep disturbances are common in individuals with Parkinson's disease. Proper sleep techniques such as going to bed at the same time every night can be helpful.

Especially for the Caregiver

  • It is important to set goals that are realistic and then strive toward them.
  • Realize that you cannot do everything, and recognize when you need help. Look for local support services such as counselors, registered nurses, speech therapists, or physical therapists.
  • Be assertive when discussing your concerns with the healthcare team or the individual you are caring for.
  • Take time for yourself, including time for rest, relaxation, hobbies, and friends.
  • Take part in support groups. Talking with others in similar situations may help you realize that you are not alone. Information on support groups can be obtained through the American Parkinson's Disease Association (800.223.2732) and the National Parkinson Foundation (800.327.4545).

What is on the horizon?

Molecular science techniques, including gene therapy, stem cell technology, and stimulation of nerve growth factors, are the newest research areas being explored in the treatment of Parkinson's disease.

The National Institute of Neurological Disorders and Stroke is trying to establish effective therapies to slow the progression of Parkinson's disease. Research was conducted to see if Mirapex and Requip slow the progression of Parkinson's disease. The results showed that Requip minimally slowed down the progression of Parkinson's disease when it was compared to levodopa. During a 46 month period, patients initially treated with Mirapex also demonstrated a reduction in dopamine neuron degeneration compared with those initially treated with levodopa. More investigations are needed for a definite conclusion.

Recent studies have also shown that Coenzyme Q10 may be effective in slowing the progression of the Parkinson's disease. This discovery has opened doors for researchers to further investigate the effectiveness of Coenzyme Q10.

References

American Parkinson's Disease association Home Page. http://www.apdaparkinson.org/user/AboutParkinson.asp. Accessed: October 2007.

The National Parkinson Foundation, Inc. Web site. Available at: http://www.parkinson.org/. Accessed: October 2007.

National Institute of Neurological Disorders and Stroke Web site. http://www.ninds.nih.gov/health_and_medical/disorders/parkinsons_disease.htm Accessed: October 2007.

Parkinson's Disease Foundation Web site. Available at: http://www.pdf.org/. Accessed: October 2007.

American Academy of Family Physicians Home Page. Parkinson's Disease. http://www.aafp.org/afp/990415ap/990415a.html. Accessed: October 2007.

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Hristova AH, Koller C. Early Parkinson's Disease: What is the Best Approach to Treatment? Drugs Aging 2000; 17(3):165-181.

Michael J. Fox Foundation Web site. Available at: http://www.michaeljfox.org/ Accessed: October 2007.

Young R. Update on Parkinson's Disease. American Family Physician Web site. Available at: http://www.aafp.org/afp/990415ap/2155.html. Accessed: October 2007.

Brain and Nervous System. In Klag MJ, Lawrence RS, Davis AR, Niparko JK, eds. Johns Hopkins Family Health Book. New York: Harper Collins; 1999.

Olanow CW, Watts RL, Koller WC. Treatment guidelines: an algorithm for the management of Parkinson's disease.Neurology 2001; 56(Suppl 5):S1-S88.

Standaert DG, Young AB. Treatment of Parkinson?s Disease. Goodman and Gilman?s -The Pharmacological Basis of Therapeutics -11th ed. McGraw & Hill; 2006: pages 533-538.

Chen JJ, Shimomura SK. Parkinsonism. Textbook of Therapeutics-Drug and Disease Management-7th ed. Lippincott Williams & Wilkins; 2000: pages 1139-1152.

Ernst ME, Gottwald MD, et al. Parkinson?s Disease. Applied Therapeutics: The Clinical Use of Drugs-8th ed. Lippincott Williams & Wilkins; 2005: pages 53-1 to 53-28.

Parkinson?s Action Network. Available at: http://www.parkinsonaction.org/ Accessed: October 2007.

Clinical Pharmacology. Gold Standard. http://www.clinicalpharmacology-ip.com. Accessed: October 2007.

Facts and Comparisons 4.0. Wolters Kluwer Health, Inc. http://factsandcomparisons.com. Accessed: October 2007.

Parkinson's Disease Health Condition Last Updated: December 2007

Note: The above information is intended to supplement, not substitute for, the expertise and judgment of your physician, pharmacist, or other healthcare professional. It is not intended to diagnose a health condition, but it can be used as a guide to help you decide if you should seek professional treatment or to help you learn more about your condition once it has been diagnosed.

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