Parkinson's Disease

Parkinson's disease (PD) belongs to a group of conditions called motor system disorders, which are the result of the loss of dopamine-producing brain cells. Parkinson's disease is a brain disorder that leads to shaking, stiffness, and difficulty with walking, balance, and coordination. Symptoms generally develop slowly over years. Parkinson's symptoms usually begin gradually and get worse over time.

Parkinson's disease (PD) belongs to a group of conditions called motor system disorders, which are the result of the loss of dopamine-producing brain cells. The four primary symptoms of PD are tremor, or trembling in hands, arms, legs, jaw, and face; rigidity, or stiffness of the limbs and trunk; bradykinesia, or slowness of movement; and postural instability, or impaired balance and coordination. As these symptoms become more pronounced, patients may have difficulty walking, talking, or completing other simple tasks. PD usually affects people over the age of 60. Early symptoms of PD are subtle and occur gradually. In some people the disease progresses more quickly than in others.

As the disease progresses, the shaking, or tremor, which affects most people with PD, may begin to interfere with daily activities including difficulty walking and talking. They may also have mental and behavioral changes, sleep problems, depression, memory difficulties, and fatigue.

One clear risk factor for Parkinson's is age. Although most people with Parkinson’s first develop the disease at about age 60, about 5 to 10 percent of people with Parkinson's have "early-onset" disease, which begins before the age of 50. Early-onset forms of Parkinson's are often, but not always, inherited, and some forms have been linked to specific gene mutations.

There is no “one way” to diagnose Parkinson’s Disease (PD). Several disorders can cause symptoms like those of Parkinson's disease. People with Parkinson's-like symptoms that result from other causes are sometimes said to have parkinsonism. While these disorders initially may be misdiagnosed as Parkinson's, certain medical tests, as well as response to drug treatment, may help to distinguish them from Parkinson's. Since many other diseases have similar features but require different treatments, it is important to make an exact diagnosis as soon as possible.

There are currently no blood or laboratory tests to diagnose nongenetic cases of Parkinson's disease. Diagnosis is based on a person's medical history and a neurological examination. Persons experiencing symptoms resembling those of PD should consider making an appointment with a neurologist with experience and specific training in the assessment and treatment of PD – referred to as a movement disorder specialist.

Although estimates vary, about 50,000 people are diagnosed with PD in the U.S. each year and about half a million people have the disease. It is anticipated that nearly one million persons will be living with PD in the U.S. by 2020. Both men and women can have Parkinson’s disease. However, the disease affects about 50 percent more men than women. Because the rate of PD increases in older adults, the burden will increase unless prevention and treatment improve.

At present, there is no cure for PD, but a variety of medications provide dramatic relief from the symptoms. Usually, affected individuals are given levodopa combined with carbidopa. Carbidopa delays the conversion of levodopa into dopamine until it reaches the brain. Nerve cells can use levodopa to make dopamine and replenish the brain's dwindling supply. Although levodopa helps at least three-quarters of parkinsonian cases, not all symptoms respond equally to the drug. Bradykinesia and rigidity respond best, while tremor may be only marginally reduced. Problems with balance and other symptoms may not be alleviated at all. Anticholinergics may help control tremor and rigidity. Other drugs, such as bromocriptine, pramipexole, and ropinirole, mimic the role of dopamine in the brain, causing the neurons to react as they would to dopamine. An antiviral drug, amantadine, also appears to reduce symptoms. In May 2006, the FDA approved rasagiline to be used along with levodopa for patients with advanced PD or as a single-drug treatment for early PD. In March 2017, the FDA approved safinamide tablets as an add-on treatment for individuals with PD how are currently taking levodopa/carbidopa and experiencing "off" episodes (when the person's medications are not working well, causing an increase in PD symptoms).

• National Institute of Neurological Disorders and Stroke
• Michael J. Fox Foundation for Parkinson's Research
• Parkinson's Foundation
• National Institute of Neurological Disorders and Stroke - Clinical Trials