Parkinson's disease is a progressive neurological disorder that affects movement. It occurs when nerve cells in the brain that produce a chemical called dopamine die or become damaged, resulting in a shortage of dopamine in the brain. Dopamine is responsible for transmitting messages that control movement and coordination, and its depletion leads to the motor symptoms of Parkinson's disease.

The symptoms of Parkinson's disease can vary from person to person, but typically include tremors, stiffness, slowness of movement, and difficulty with balance and coordination. Other symptoms may include changes in speech and writing, difficulty swallowing, constipation, and sleep disturbances. As the disease progresses, people with Parkinson's may also experience cognitive and behavioral changes, such as depression, anxiety, and memory problems.

There is currently no cure for Parkinson's disease, but there are treatments available that can help manage symptoms and improve quality of life. Medications such as levodopa and dopamine agonists can help replace the dopamine that is lost in the brain, and other medications can help with specific symptoms like tremors or sleep disturbances. In some cases, surgery may also be an option.

In addition to medical treatment, lifestyle modifications such as exercise, physical therapy, and speech therapy can also help improve symptoms and slow the progression of the disease. It's important for people with Parkinson's disease to work closely with their healthcare team to develop a comprehensive treatment plan tailored to their specific needs.

In Parkinson's disease, certain nerve cells (neurons) in the brain gradually break down or die. Many of the symptoms are due to a loss of neurons that produce a chemical messenger in your brain called dopamine. When dopamine levels decrease, it causes abnormal brain activity, leading to impaired movement and other symptoms of Parkinson's disease.

The cause of Parkinson's disease is unknown, but several factors appear to play a role, including:

• Genes. Researchers have identified specific genetic mutations that can cause Parkinson's disease. But these are uncommon except in rare cases with many family members affected by Parkinson's disease.
• However, certain gene variations appear to increase the risk of Parkinson's disease but with a relatively small risk of Parkinson's disease for each of these genetic markers.
• Environmental triggers. Exposure to certain toxins or environmental factors may increase the risk of later Parkinson's disease, but the risk is relatively small.

Researchers have also noted that many changes occur in the brains of people with Parkinson's disease, although it's not clear why these changes occur. These changes include:

• The presence of Lewy bodies. Clumps of specific substances within brain cells are microscopic markers of Parkinson's disease. These are called Lewy bodies, and researchers believe these Lewy bodies hold an important clue to the cause of Parkinson's disease.
• Alpha-synuclein found within Lewy bodies. Although many substances are found within Lewy bodies, scientists believe an important one is the natural and widespread protein called alpha-synuclein (a-synuclein). It's found in all Lewy bodies in a clumped form that cells can't break down. This is currently an important focus among Parkinson's disease researchers.

Because the cause of Parkinson's is unknown, proven ways to prevent the disease also remain a mystery.

Some research has shown that regular aerobic exercise might reduce the risk of Parkinson's disease.

Some other research has shown that people who consume caffeine — which is found in coffee, tea and cola — get Parkinson's disease less often than those who don't drink it. Green tea is also related to a reduced risk of developing Parkinson's disease. However, it is still not known whether caffeine actually protects against getting Parkinson's, or is related in some other way. Currently there is not enough evidence to suggest drinking caffeinated beverages to protect against Parkinson's.

Parkinson's disease can't be cured, but medications can help control your symptoms, often dramatically. In some more advanced cases, surgery may be advised.

Your doctor may also recommend lifestyle changes, especially ongoing aerobic exercise. In some cases, physical therapy that focuses on balance and stretching also is important. A speech-language pathologist may help improve your speech problems.

Medications

Medications may help you manage problems with walking, movement and tremor. These medications increase or substitute for dopamine.

People with Parkinson's disease have low brain dopamine concentrations. However, dopamine can't be given directly, as it can't enter your brain.

You may have significant improvement of your symptoms after beginning Parkinson's disease treatment. Over time, however, the benefits of drugs frequently diminish or become less consistent. You can usually still control your symptoms fairly well.

Medications your doctor may prescribe include:

• Carbidopa-levodopa. Levodopa, the most effective Parkinson's disease medication, is a natural chemical that passes into your brain and is converted to dopamine.
• Levodopa is combined with carbidopa (Lodosyn), which protects levodopa from early conversion to dopamine outside your brain. This prevents or lessens side effects such as nausea.
• Side effects may include nausea or lightheadedness (orthostatic hypotension).
• After years, as your disease progresses, the benefit from levodopa may become less stable, with a tendency to wax and wane ("wearing off").
• Also, you may experience involuntary movements (dyskinesia) after taking higher doses of levodopa. Your doctor may lessen your dose or adjust the times of your doses to control these effects.
• Inhaled carbidopa-levodopa. Inbrija is a new brand-name drug delivering carbidopa-levodopa in an inhaled form. It may be helpful in managing symptoms that arise when oral medications suddenly stop working during the day.
• Carbidopa-levodopa infusion. Duopa is a brand-name medication made up of carbidopa and levodopa. However, it's administered through a feeding tube that delivers the medication in a gel form directly to the small intestine.
• Duopa is for patients with more-advanced Parkinson's who still respond to carbidopa-levodopa, but who have a lot of fluctuations in their response. Because Duopa is continually infused, blood levels of the two drugs remain constant.
• Placement of the tube requires a small surgical procedure. Risks associated with having the tube include the tube falling out or infections at the infusion site.
• Dopamine agonists. Unlike levodopa, dopamine agonists don't change into dopamine. Instead, they mimic dopamine effects in your brain.
• They aren't as effective as levodopa in treating your symptoms. However, they last longer and may be used with levodopa to smooth the sometimes off-and-on effect of levodopa.
• Dopamine agonists include pramipexole (Mirapex), ropinirole (Requip) and rotigotine (Neupro, given as a patch). Apomorphine (Apokyn) is a short-acting injectable dopamine agonist used for quick relief.
• Some of the side effects of dopamine agonists are similar to the side effects of carbidopa-levodopa. But they can also include hallucinations, sleepiness and compulsive behaviors such as hypersexuality, gambling and eating. If you're taking these medications and you behave in a way that's out of character for you, talk to your doctor.
• MAO B inhibitors. These medications include selegiline (Zelapar), rasagiline (Azilect) and safinamide (Xadago). They help prevent the breakdown of brain dopamine by inhibiting the brain enzyme monoamine oxidase B (MAO B). This enzyme metabolizes brain dopamine. Selegiline given with levodopa may help prevent wearing-off.
• Side effects of MAO B inhibitors may include headaches, nausea or insomnia. When added to carbidopa-levodopa, these medications increase the risk of hallucinations.
• These medications are not often used in combination with most antidepressants or certain narcotics due to potentially serious but rare reactions. Check with your doctor before taking any additional medications with an MAO B inhibitor.
• Catechol O-methyltransferase (COMT) inhibitors. Entacapone (Comtan) and opicapone (Ongentys) are the primary medications from this class. This medication mildly prolongs the effect of levodopa therapy by blocking an enzyme that breaks down dopamine.
• Side effects, including an increased risk of involuntary movements (dyskinesia), mainly result from an enhanced levodopa effect. Other side effects include diarrhea, nausea or vomiting.
• Tolcapone (Tasmar) is another COMT inhibitor that is rarely prescribed due to a risk of serious liver damage and liver failure.
• Anticholinergics. These medications were used for many years to help control the tremor associated with Parkinson's disease. Several anticholinergic medications are available, including benztropine (Cogentin) or trihexyphenidyl.
• However, their modest benefits are often offset by side effects such as impaired memory, confusion, hallucinations, constipation, dry mouth and impaired urination.
• Amantadine. Doctors may prescribe amantadine alone to provide short-term relief of symptoms of mild, early-stage Parkinson's disease. It may also be given with carbidopa-levodopa therapy during the later stages of Parkinson's disease to control involuntary movements (dyskinesia) induced by carbidopa-levodopa.
• Side effects may include a purple mottling of the skin, ankle swelling or hallucinations.

Surgical procedures

Deep brain stimulation. In deep brain stimulation (DBS), surgeons implant electrodes into a specific part of your brain. The electrodes are connected to a generator implanted in your chest near your collarbone that sends electrical pulses to your brain and may reduce your Parkinson's disease symptoms.

Your doctor may adjust your settings as necessary to treat your condition. Surgery involves risks, including infections, strokes or brain hemorrhage. Some people experience problems with the DBS system or have complications due to stimulation, and your doctor may need to adjust or replace some parts of the system.

Deep brain stimulation is most often offered to people with advanced Parkinson's disease who have unstable medication (levodopa) responses. DBS can stabilize medication fluctuations, reduce or halt involuntary movements (dyskinesia), reduce tremor, reduce rigidity, and improve slowing of movement.

DBS is effective in controlling erratic and fluctuating responses to levodopa or for controlling dyskinesia that doesn't improve with medication adjustments.

However, DBS isn't helpful for problems that don't respond to levodopa therapy apart from a tremor. A tremor may be controlled by DBS even if the tremor isn't very responsive to levodopa.

Although DBS may provide sustained benefit for Parkinson's symptoms, it doesn't keep Parkinson's disease from progressing.

Because there have been infrequent reports that the DBS therapy affects the movements needed for swimming, the Food and Drug Administration recommends consulting with your doctor and taking water safety precautions before swimming.