What is Parkinson's disease?Parkinson's disease is the second most common neurodegenerative disorder worldwide after Alzheimer's disease. Parkinson's affects nerve cells in the part of the mid-brain known as the substantia nigra, responsible for muscle movement. The result is tremors, rigidity, slow movements and difficulties with balance . Its signs and symptoms worsen over time, eventually leading to cognitive problems including dementia. But although Parkinson's may result in disability, the disease often moves slowly, and most people have a number of years of only minor disability following a diagnosis.

The motor symptoms alone are known as parkinsonism - they may be due to Parkinson's disease, or to a number of other causes that may be temporary or reversible.

The disease is named after James Parkinson, a British physician who published the first detailed description of the condition in 1817. Famous Americans including actor Michael J. Fox and boxer Muhammed Ali have the condition, and have raised awareness of it via books, appearances and interviews on behalf of groups such as the National Parkinson Foundation.

What are the causes?There appears to be a genetic component, as people with a first-degree relative who has Parkinson's, such as a parent, child or sibling, are at greater risk. In March of 2011, researchers at Mount Sinai School of Medicine published research indicating that mutations in a gene called LRRK2 are associated with the most common inherited form of the condition.

In addition, and even in people who are genetically predisposed to Parkinson's disease, many experts believe that environmental exposures, such as unusual exposure to herbicides and pesticides, increase a person's risk of developing Parkinson's disease.

Certain drugs, when taken for long periods of time or in amounts greater than recommended, can cause parkinsonism. These include medications such as Haldol (Haloperidol) and Thorazine (Chlorpromazine), used to treat psychiatric disorders, as well as drugs used to treat nausea, such as Reglan (Metoclopramide ). The anti-seizure drug, Depakene (Valproic Acid), also may cause some of the features of parkinsonism, notably severe tremor. These medications do not result in Parkinson's disease, however, and symptoms resolve when the medications are no longer used.

Who is likely to get it?Parkinson's disease generally begins in middle or late life, and the risk continues to increase as people age. Other risk factors include:

What are the symptoms?Initial symptoms may include: an arm that refuses to swing when you walk, a mild tremor in the fingers of one hand or slurred speech. You may lack energy, feel sad or have difficulty sleeping. Daily activities may take longer than normal. Other signs and symptoms can include:

How is it diagnosed?A diagnosis of Parkinson's disease is made based on medical history and a thorough neurological evaluation - there are no specific blood test or x-ray results that can definitively support the diagnosis . Your physician will inquire about any medications you take and whether you have a family member with Parkinson's. The doctor will assess your balance, walking, coordination and dexterity. Even if the symptoms are not apparent to you, a trained physician may detect subtle signs of parkinsonism - reduced facial expressions, a lack of gestures or a slight tremor.

Excerpt from:
Parkinson's Disease - Dr. Weil's Condition Care Guide