Parkinson's disease is a disorder of the brain that leads to shaking (tremors) and difficulty with walking, movement, and coordination.

Parkinson's disease was first described in England in 1817 by Dr. James Parkinson. The disease most often develops after age 50. It is one of the most common nervous system disorders of the elderly. Sometimes Parkinson's disease occurs in younger adults, but is rarely seen in children. It affects both men and women.

In some cases, Parkinson's disease occurs in families. When a young person is affected, it is usually because of a form of the disease that runs in families.

Nerve cells use a brain chemical called dopamine to help control muscle movement. Parkinson's disease occurs when the nerve cells in the part of the brain that makes dopamine are slowly destroyed. Without dopamine, the nerve cells in that part of the brain cannot properly send messages. This leads to the loss of muscle function. The damage gets worse with time. The exact reason why the brain cells waste away is unknown.

Parkinson's in children may occur because the nerves are not as sensitive to dopamine. Parkinson's is rare in children.

The term "parkinsonism" refers to any condition that involves the types of movement changes seen in Parkinson's disease. Parkinsonism may be caused by other disorders (such as secondary parkinsonism) or certain medications.

The disorder may affect one or both sides of the body. How much function is lost can vary.

Symptoms may be mild at first. For instance, the patient may have a mild tremor or a slight feeling that one leg or foot is stiff and dragging.

Symptoms include:

• Automatic movements (such as blinking) slow or stop
• Constipation
• Difficulty starting or continuing movement, such as starting to walk or getting out of a chair
• Drooling
• Impaired balance and walking
• Lack of expression in the face (mask-like appearance)
• Loss of small or fine hand movements (writing may become small and difficult to read, and eating becomes harder)
• Muscle aches and pains (myalgia)
• Problems with movement
• Rigid or stiff muscles (often beginning in the legs)
• Shaking, tremors
  • Tremors usually occur in the limbs at rest, or when the arm or leg is held out
  • Tremors go away during movement
  • Over time, tremor can be seen in the head, lips, tongue, and feet
  • May be worse when tired, excited, or stressed
  • Finger-thumb rubbing (pill-rolling tremor) may be present
• Shuffling gait
• Slowed movements
• Slowed, quieter speech and monotone voice
• Stooped position

Other symptoms:

• Anxiety, stress, and tension
• Confusion
• Dementia
• Depression
• Fainting
• Hallucinations
• Loss of muscle function or feeling
• Memory loss
• Oily skin (seborrhea)

The health care provider may be able to diagnose Parkinson's disease based on your symptoms and a physical examination. However, the symptoms can be difficult to assess, particularly in the elderly. The signs (tremor, change in muscle tone, problems walking, unsteady posture) become more clear as the illness progresses.

An examination may show:

• Difficulty starting or finishing voluntary movements
• Jerky, stiff movements
• Muscle atrophy
• Parkinson's tremors
• Variation in heart rate

Reflexes should be normal.

Tests may be needed to rule out other disorders that cause similar symptoms.

There is no known cure for Parkinson's disease. The goal of treatment is to control symptoms.

Medications control symptoms, mostly by increasing the levels of dopamine in the brain. As symptoms change, the following may need to be altered:

• Type of medication
• Dose
• Amount of time between doses
• How the medications are taken

Work closely with your doctors and therapists to adjust the treatment program. Never change or stop taking any medications without talking with your doctor.

Many medications can cause severe side effects, including hallucinations, nausea, vomiting, diarrhea, and delirium. Monitoring and follow-up by the health care provider is important.

Eventually, symptoms such as stooped posture, frozen movements, and speech difficulties may not respond very well to drug treatment.

Medications used to treat symptoms of Parkinson's disease are:

• Levodopa (L-dopa), Sinemet, levodopa and carbidopa (Atamet)
• Pramipexole (Mirapex), ropinirole (Requip), bromocriptine (Parlodel)
• Selegiline (Eldepryl, Deprenyl), rasagiline (Azilect)
• Amantadine or anticholinergic medications -- to reduce early or mild tremors
• Entacapone -- to prevent the breakdown of levodopa

Lifestyle changes that may be helpful for Parkinson's disease:

• Good general nutrition and health
• Exercising, but adjusting the activity level to meet changing energy levels
• Regular rest periods and avoiding stress
• Physical therapy, speech therapy, and occupational therapy
• Railings or banisters placed in commonly used areas of the house
• Special eating utensils
• Social workers or other counseling services to help you cope with the disorder and get assistance (such as Meals-on-Wheels)

Less commonly, surgery may be an option for patients with very severe Parkinson's disease who no longer respond to many medications. These surgeries do not cure Parkinson's, but may help some patients:

• In deep brain stimulation (DBS), the surgeon implants electrical stimulators in specific areas of the brain to help with movement.
• Another type of surgery destroys brain tissues that cause Parkinson's symptoms.

Support groups may help you cope with the changes caused by the disease.

See: Parkinson's disease - support group

Untreated, the disorder will get worse until a person is totally disabled. Parkinson's may lead to a deterioration of all brain functions, and an early death.

Most people respond to medications. How much the medications relieve symptoms, and for how long can be very different in each person. The side effects of medications may be severe.

• Difficulty performing daily activities
• Difficulty swallowing or eating
• Disability (differs from person to person)
• Injuries from falls
• Pneumonia from breathing in (aspirating) saliva
• Side effects of medications

Call your health care provider if:

• You have symptoms of Parkinson's disease
• Symptoms get worse
• New symptoms occur

Also tell the health care provider about medication side effects, which may include:

• Changes in alertness, behavior or mood
• Delusional behavior
• Dizziness
• Hallucinations
• Involuntary movements
• Loss of mental functions
• Nausea and vomiting
• Severe confusion or disorientation

Also call your health care provider if the condition gets worse and home care is no longer possible.

Lang A. Parkinsonism. In: Goldman L, Ausiello D, eds. Cecil Textbook of Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 433.

Miyasaki JM, Shannon K, Voon V, Ravina B, Kleiner-Fisman G, Anderson K, et al. Practice Parameter: evaluation and treatment of depression, psychosis, and dementia in Parkinson's disease (an evidence-based review): report of the Quality Standards Subcommittee of the American Academy of Neurology. Neurology. 2006;66:996-1002.

Suchowersky O, Reich S, Perlmutter J, Zesiewicz T, Gronseth G, Weiner WJ. Quality Standards Subcommittee of the American Academy of Neurology. Practice Parameter: diagnosis and prognosis of new onset Parkinson disease (an evidence-based review): report of the Quality Standards Subcommittee of the American Academy of Neurology. Neurology. 2006.66:968-975.

Pahwa R, Factor SA, Lyons KE, Ondo WG, Gronseth G, Bronte-Stewart H, et al. Practice Parameter: treatment of Parkinson disease with motor fluctuations and dyskinesia (an evidence-based review): report of the Quality Standards Subcommittee of the American Academy of Neurology. Neurology. 2006;66:983-995.