Parkinson's disease

Parkinson's disease is a progressive, degenerative neurological disorder.


Causes/associated factors
Parkinson's disease is caused by the death or damage of nerve cells in an area of the brain called the substantia nigra. The cells in the substantia nigra produce a chemical in the brain called dopamine, which helps neurons transmit messages to control muscle activity. With Parkinson's disease, dopamine production gradually decreases and an imbalance between dopamine levels and acetylcholine (another brain chemical) results. This causes the symptoms of Parkinson's to begin. The symptoms progressively worsen as more cells are damaged or destroyed. The cause of the cell destruction is unknown.
Parkinson's disease is one of the most common movement-affecting disorders. About 50,000 people in the United States are diagnosed with Parkinson's disease every year. The condition is a disease of late middle age. On average, Parkinson's disease develops at age 60, and the rate of new cases peaks near age 75. Five percent of people who have Parkinson's disease are under age 40, however.

Recent research indicates that heredity may play a role in the development of Parkinson/symptoms

Parkinson's disease affects people differently. It may progress gradually or rapidly, causing minor problems with motor movement or severe disability. Here's a description of the most common symptoms.
Parkinson's disease often causes muscles to remain tense or contracted. This leads to stiffness, weakness and muscle ache, especially in the arms, legs and neck. If you move the arm of someone who has Parkinson's disease, it may produce short, jerky movements. This is often called "cogwheel" rigidity.

Parkinson's disease typically causes a tremor (shaking) that's most noticeable when the person rests quietly. The tremor is often called "pill rolling" because many people who have the disease continually rub their thumb and forefinger back and forth as if they were rolling a pill or coin between their fingers. The tremor often starts in the hand, but may begin in the foot or jaw and can even affect the lips, tongue or neck. The tremor typically affects one side or area of the body initially, but eventually progresses to both sides of the body.

The ability to initiate spontaneous or automatic movement may become difficult. The person may be able to dress without help in the morning, but later in the day have difficulty with the same task. People who have Parkinson's disease often develop a slow, shuffling gait.

Parkinson's disease may affect the person's balance. The person may fall more easily or begin to lean forward or backward. Balance problems often cause people who have Parkinson's disease to have a hunched posture.

Depression is common in people who have Parkinson's disease. Other emotional changes often occur as well.

Other symptoms may include difficulty swallowing and chewing, bowel and bladder problems, skin conditions (particularly oily skin on the face), and trouble speaking or sleeping.

Sadly, people who have Parkinson's may eventually become immobilized and unable to care for themselves.

Diagnosis
The doctor, often a neurologist (a doctor who specializes in nervous system disorders), will ask questions about the person's symptoms and medical history and do a thorough physical exam. Certain lab tests may be needed to rule out other possible conditions. However, there is no test to confirm a diagnosis of Parkinson's disease. Due to the often nonspecific symptoms, the condition is sometimes suspected for a period of time before a definite diagnosis is made.

Treatment
Medication
Many doctors now tailor medications to the stage of disease and severity of symptoms. A medication called levodopa has been used for many years to treat the disabling symptoms of Parkinson's disease. Levodopa is converted to dopamine in the nerve cells, which often decreases muscle stiffness and improves movement. It may help tremors and balance only slightly, however. Levodopa can help people who have Parkinson's disease function at a more normal level for a while, but the medication can't repair the nerve cell loss or stop the disease from progressing. In many cases, levodopa may be "saved" for use in the later stages of the disease.

The most common side effects of levodopa include nausea, vomiting, low blood pressure, involuntary movements and restlessness. Large doses taken for long periods of time may cause jerking, twitching or nodding movements. Symptoms may increase as each dose wears off. Symptoms that come and go during the day may indicate the effectiveness of the medication is changing or the disease is progressing.

To decrease possible side effects as well as the required dosage amounts, the medication carbidopa may be combined with levodopa. This combination medication is called carbidopa-levodopa (brand name Sinemet). Because protein may affect the absorption of levodopa, meals may need to be timed around the medication. Sometimes changes in protein intake are recommended.

Early in the illness, other medications may be prescribed alone or in conjunction with levodopa. These medications include bromocriptine, pergolide, pramipexole (Mirapex) and ropinirole (Requip). These medications mimic the action of dopamine in the brain and are often used to decrease early symptoms of Parkinson's disease. Sometimes they're used to extend levodopa's effectiveness. Common side effects include paranoia, hallucinations, confusion, abnormal movements, nightmares, nausea and vomiting, constipation, dizziness upon standing and irregular heartbeat.

Selegiline is another medication that can sometimes delay the need for levodopa by up to a year. When it's taken with levodopa, selegiline often enhances and extends the medication's effectiveness. Common side effects include nausea, sleep difficulties, and lightheadedness or dizziness with position changes.

The doctor may also prescribe anticholinergic drugs to restore the balance between dopamine and acetylcholine. These medications may decrease tremors and muscle stiffness, but their effectiveness is limited. These medications may also be taken in combination with levodopa or bromocriptine. Common side effects include dry mouth, nausea, constipation, urine retention, visual changes, confusion, agitation and heart palpitations.

An antiviral medication called amantadine, taken alone or with other medications, may also help reduce early symptoms of Parkinson's disease. Rare side effects include nausea, constipation, insomnia, blotchy skin, swelling of the ankles, confusion, restlessness and depression.

The medication tolcapone (Tasmar) is a newer medication used to treat Parkinson's disease. When taken with levodopa, it works by blocking a key enzyme responsible for breaking down levodopa before it reaches the brain. It may improve activities such as speaking, writing, walking and dressing.

A person who has Parkinson's disease should never change or stop taking any prescribed medication without his or her doctor's recommendation. Rapid withdrawal could cause serious side effects.

Surgery
Surgery may be recommended if the person has severe tremors, symptoms that don't respond to medications, or significant medication side effects. Of course, it's important to evaluate the risks and benefits before surgery.

With a procedure called cryothalamotomy, a cold, metal-tipped probe is inserted into the thalamus (the relay center of the brain) to destroy the cells that produce the tremors.
With a newer procedure called pallidotomy, certain brain cells are destroyed and a lesion is surgically created in the brain to interrupt neural pathways. This surgery is usually a last resort to decrease tremors, stiffness and slow movement.
These and other surgical approaches continue to be studied for Parkinson's disease treatment.

Deep brain stimulation
Deep brain stimulation can help control the tremors of Parkinson's disease. With this option, a wire is surgically implanted deep in the brain. It's connected to a pulse generator, which is implanted near the collarbone. When a tremor begins, the person activates the device by passing a handheld magnet over the generator. Then, the system delivers an electrical impulse that blocks the brain signals causing the tremor.

Other therapies
In some cases, speech therapy, physical therapy, muscle-strengthening programs and regular exercise can improve symptoms. Interventions at home, such as handrails on the walls and nonslip surfaces, can help mobility and reduce the risk of injury. Individual recommendations may be made regarding vitamin and nutritional intake. Medications may be prescribed to help treat other problems often associated with Parkinson's disease, such as depression or constipation. Finally, people with Parkinson's disease and their families need strong emotional support.


Complications
Complications of Parkinson's disease may include:
depression
dementia
pneumonia
constipation
urinary retention
falls
fractures
debilitation

Pregnancy-specific information
Pregnancy is not a risk factor for Parkinson's disease.

Senior-specific information
Again, Parkinson's disease is most common in older adults.