Understanding Parkinson's Disease -- Diagnosis and Treatment

How Is Parkinson's Disease Diagnosed?

Usually, the outward symptoms of Parkinson's are distinctive enough for a doctor to make a diagnosis in the office. There is no blood test that confirms the diagnosis. In some cases, though, a DaTSCAN, which uses a radioactive agent and a special camera, can detect early signs of Parkinson's. But if you don't respond to the drugs used to treat Parkinson's disease, it’s possible you may have another type of movement disorder that causes the same type of symptoms. Doing additional tests can help your doctor determine if some other problem is causing your Parkinsonian symptoms.

What Are the Treatments for Parkinson’s Disease?

Most Parkinson's disease treatments aim to restore the proper balance of the neurotransmitters acetylcholine and dopamine by increasing dopamine levels. Drugs are the standard way of doing this, but many patients, as their disease worsens, may be candidates for implantation of a deep brain stimulator or DBS.

 

Conventional Medicine for Parkinson's Disease

Symptoms of Parkinson’s disease can often be effectively controlled for years with medication.

Levodopa -- also called L-dopa -- is the drug most often prescribed. The body metabolizes it to produce dopamine. Giving dopamine directly is ineffective, because the brain's natural defense blocks it from being used by the body. To suppress nausea and other possible side effects, levodopa is used in conjunction with a related drug called carbidopa. The combination is commercially known as Sinemet.

Rarely, a patient cannot tolerate carbidopa and will take levodopa alone. If you take only levodopa, it's important not to take it at the same time as food or vitamins containing vitamin B-6, which interferes with its effectiveness.

Most doctors try to postpone starting patients on levodopa as long as possible, because the drug tends to lose effectiveness over time. However, there is some controversy about waiting to begin treatment with levodopa because it can be so beneficial. Researchers have thus investigated ways to offset the loss of effectiveness.

COMT inhibitors such as tolcapone (Tasmar) and entacapone (Comtan) are drugs that are taken with levodopa. They prolong the duration of symptom relief by blocking the action of an enzyme that breaks down levodopa. Tasmar, however, is rarely used, because it can cause liver damage.

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Stalevo is a combination tablet that combines carbidopa/levodopa with entacapone. While carbidopa reduces the side effects of levodopa, entacapone extends the time levodopa is active in the brain.

MAO-B inhibitors also block the action of an enzyme that breaks down dopamine. They may be taken alone early in Parkinson's disease or with other drugs as the disease progresses. MAO-B inhibitors include selegiline (Eldepryl) and rasagaline (Azilect). They are usually used alone, because combining them with other drugs can cause unwanted side effects.

Dopamine agonists are dopamine-like drugs that directly imitate dopamine's activity in the brain. Pramipexole (Mirapex), rotigotine (Neuropro), and ropinirole (Requip) used alone or in combination with L-dopa treat the motor symptoms of Parkinson's disease.

Other medicationsprescribed for Parkinson's disease include apomorphine, benztropine, amantadine, selegiline, and anticholinergic drugs; all can help control various symptoms -- in some cases by releasing dopamine from nerve cells, in others by reducing the effects of acetylcholine, a neurotransmitter that can cause a drop in dopamine.

Other Types of Treatment for Parkinson’s Disease

Neurologists and neurosurgeons have explored various ways of grafting dopamine-producing cells in the brain of those with Parkinson’s disease, rather than trying to correct the neurotransmitter imbalance with drugs. There is research still in the early stage on using stem cells for this purpose.

Another surgical technique creates lesions in the globus pallidus or thalamus. These are the parts of the brain involved in Parkinson's disease. This was successful for many years but has mostly been replaced by deep brain stimulation (DBS). In this procedure, a wire is placed deep inside the brain in a specific location depending on the symptoms that need to be treated. DBS can provide dramatic improvements in many people and is a highly successful therapy for both rigidity and tremor.

Scientists are also investigating the use of glial cell-derived nerve growth factor to treat Parkinson's and other neurodegenerative diseases. This substance is produced naturally by tissues throughout the body. Some experiments indicate that injections of this nerve growth factor may help preserve and even restore nerve cells in the brain and spinal cord -- specifically those that produce dopamine and that help initiate muscle movement. Time will tell if this and other research will be beneficial.

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Some treatments focus on the effects of the disorder, rather than the causes. Your doctor might refer you to a physical therapist to restore normal body alignment, enhance balance and motor responses, and improve the ability to initiate motion. A physical therapist may also teach muscle-strengthening exercises to help with speaking or swallowing.

It is very important to maintain a daily exercise program and to remain socially active. In many Parkinson's patients, a weakening of social ties because of physical difficulties can lead to depression. Antidepressants can help. In addition, the American Parkinson Disease Association can provide information about support groups and exercise classes in your area -- valuable sources for companionship.

WebMD Medical Reference Reviewed by Neil Lava, MD on February 11, 2017

Sources

SOURCES: 

Journal of the American Medical Association. 

Academy of American Family Physicians. 

National Parkinson Foundation. 

American Parkinson Disease Foundation. 

Teva Pharmaceuticals, Inc.

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