Parkinson's disease is a degenerative disorder of the central nervous system.

Parkinson's disease occurs when nerve cells, or neurons, in an area of the brain known as the substantia nigra die or become impaired. Normally, these neurons produce an important brain chemical known as dopamine. At least 500,000 people in the United States currently have PD. Parkinson's disease belongs to a group of conditions called movement disorders. Parkinson's disease is progressive, meaning the signs and symptoms become worse over time. But although Parkinson's disease may eventually be disabling, the disease often progresses gradually. Parkinson disease affects movement (motor symptoms). Typical other symptoms include disorders of mood, behavior, thinking, and sensation (non-motor symptoms). Individual patients' symptoms may be quite dissimilar and progression of the disease is also distinctly individual. Parkinson's usually begins around age 60. It is more common in men than in women. Symptoms of Parkinson's disease often start on one side of the body first and then affect both sides.

There are many secondary symptoms associated with Parkinson's disease.

Parkinson's disease patients may notice that they are weaker or more tired. Symptoms include disorders of mood, behavior, thinking, and sensation. Poor balance is due to the impairment or loss of the reflexes that adjust posture in order to maintain balance. Falls are common in people with Parkinson's. Shaking (muscle tremor). This is one of the first symptoms in three-quarters of people, and affects most people with Parkinson's disease. Bradykinesia is the phenomenon of a person experiencing slow movements. In addition to slow movements, a person with bradykinesia will probably also have incomplete movement, difficulty initiating movements and sudden stopping of ongoing movement. The progressive loss of voluntary and involuntary muscle control produces a number of secondary symptoms associated with Parkinson's. Postural instability, or impaired balance and coordination, causes patients to develop a forward or backward lean and to fall easily.

Parkinson's disease requires broad-based management including patient and family education, support group services, general wellness maintenance, exercise, and nutrition.

Medications can help manage problems with walking, movement and tremor by increasing the brain's supply of dopamine. Amantadine may also be added to carbidopa-levodopa therapy for people in the latter stages of Parkinson's disease. Catechol-O-methyl-transferase (COMT) inhibitors drugs prolong the effect of carbidopa-levodopa therapy by blocking an enzyme that breaks down dopamine. Tolcapone (Tasmar) is a potent COMT inhibitor that easily crosses the blood-brain barrier. A medicine called levodopa is often given to people who have Parkinson's disease. Called "L-dopa," this medicine increases the amount of dopamine in the body and has been shown to improve a person's ability to walk and move around. Thalamotomy involves the destruction of small amounts of tissue in the thalamus - a major brain center for relaying messages and transmitting sensations.

Parkinson's Disease Treatment

• Carbidopa and benserazide are dopa decarboxylase inhibitors.
• Tolcapone inhibits the COMT enzyme, thereby prolonging the effects of L-dopa, and so has been used to complement L-dopa.
• Selegiline and rasagiline reduce the symptoms by inhibiting monoamine oxidase-B (MAO-B).
• An antiviral drug, amantadine, can help reduce symptoms of PD and levodopa-induced dyskinesia.
• COMT (catechol-O-methyl-transferase) inhibitors are a new class of drugs that stop the breakdown of dopamine.
• Other therapies that are important for managing and coping with Parkinson's disease include physiotherapy, speech therapy, and occupational therapy.
• Amantadine acts like a dopamine replacement drug but works on different sites in the brain.