Parkinson’s Disease: What it is, Symptoms & Causes

What is Parkinson’s disease?

Parkinson’s disease is a neurodegenerative disease, which means that certain cells in the brain are gradually destroyed. In Parkinson’s disease, the cells that are destroyed are those that produce dopamine, a chemical that plays an important role in controlling movement. The disease therefore causes a gradual loss of the ability to control certain types of movement.

Symptoms appear gradually and worsen over time, but the disease progresses at a different rate for each person. Parkinson’s disease is not fatal and doesn’t usually shorten life expectancy. However, as the disease progresses, serious complications can increase certain risks. For example, balance problems can lead to falls, and swallowing problems can lead to aspiration pneumonia, both of which can be fatal.

Who can get Parkinson’s disease?

Each year, approximately 10,000 Canadians are diagnosed with parkinsonism, an umbrella term that includes Parkinson’s disease, secondary parkinsonism and atypical parkinsonism. Most parkinsonism cases are due to Parkinson’s disease (PD).

The average age of onset is 60, but 5–10% of cases occur before age 40 and 20% before age 50 (called young-onset or early-onset PD). Men are more likely to develop Parkinson’s disease than women (60% of cases vs. 40%).

What causes Parkinson’s disease?

Parkinson’s disease is a multifactorial disease, which means that many factors can play a role in its development. The most important one is age. The more you age, the higher the risk of developing PD: it affects 1 person in 400 at age 60, but 1 in 40 at age 80.

Other risk factors:

• Genetics. Research has shown that mutations on certain genes increase the risk of Parkinson’s disease.
• Exposure to certain environmental factors or toxins. For example, research has shown an association between pesticide exposure and the development of Parkinson’s disease, particularly in farmers.

What are the symptoms of Parkinson’s disease?

The symptoms of Parkinson’s disease vary greatly from person to person. Initially, some form of motor symptoms will be present. Non-motor symptoms may also be present at the time of diagnosis or may develop as the disease progresses.

Motor symptoms

Motor symptoms affect movement. At first, they tend to affect only one side of the body. Eventually, however, both sides may be affected. For many people, symptoms fluctuate from day to day, so the person has good days and bad days.

• Bradykinesia, i.e., difficulty starting and maintaining movement. Movements are slower and smaller. For example, shuffling or taking smaller steps when walking, handwriting becoming smaller, voice becoming weaker, lack of facial expressions, decreased blinking. This can also lead to drooling and difficulty swallowing.
• Resting tremors. They occur when muscles of the hand, foot or jaw are at rest and usually stop during movement. While tremors are the most noticeable sign of Parkinson’s disease, they do not affect all patients. About a third of patients do not have them.

• Rigidity or stiffness in the limbs or other parts of the body. As the disease progresses, stiffness increases and makes movement more difficult.
• Balance problems, especially when changing position, which increase the risk of falls.
• Freezing episodes, especially when starting to walk. The person feels as if their feet are stuck to the floor for a few seconds before they are able to take the first step.

Non-motor symptoms

Several non-motor symptoms have been associated with Parkinson’s disease. Some of them may develop before motor symptoms appear, but are often overlooked, because people associate them with the effects of normal aging.

• Depression, anxiety or apathy (lack of interest to things or life in general)
• Sleep problems such as trouble staying asleep, daytime sleepiness, acting out dreams (REM-sleep behaviour disorder), restless legs syndrome
• Constipation
• Bladder problems
• Changes in smell and taste
• Sudden drop in blood pressure when changing position (orthostatic hypotension)
• Leg swelling
• Heavy sweating
• Fatigue
• Sexual problems, such as change in sex drive, erectile dysfunction

Parkinson’s disease can also cause dementia usually in later stages of the disease and in older people, as the disease spreads to parts of the brain responsible for memory and concentration.

How does Parkinson’s disease progress?

The following 5-stage classification dates back to 1967 and does not take non-motor symptoms into account, but it provides a broad overview of the progression of Parkinson’s disease. It’s important to understand that the rate of progression varies from person to person and cannot be predicted.

• Stage 1: Mild symptoms that typically involve only one side of the body. Common symptoms include slight tremors, minimal stiffness, or minor changes in posture or walking. Daily activities are usually unaffected, and the symptoms might not be noticeable to others.
• Stage 2: Motor symptoms are more noticeable and typically affect both sides of the body. The tremors, rigidity, and bradykinesia (slowness of movement) are more pronounced. Daily activities are still possible but become more difficult.
• Stage 3: Balance is significantly impaired, increasing the risk of falls. The person is functionally impaired but can still live independently with assistance.
• Stage 4: Symptoms are severe and significantly limit the ability to perform daily activities. Walking may become very difficult. The person may need help with most activities of daily living, making living alone difficult.
• Stage 5: The person is often bedridden because stiffness and other motor symptoms make standing and walking extremely difficult. There is a high level of dependence on caregivers for all aspects of daily life, and 24-hour care is usually required at this stage.

How is Parkinson’s disease treated?

There is currently no cure for Parkinson’s disease. However, treatments are available to help reduce motor and non-motor symptoms and improve quality of life.

For motor symptoms, the cornerstone of therapy is to increase dopamine levels in the brain. The preferred treatment for most patients is a drug called levodopa. However, other medications may be prescribed depending on the stage of the disease, symptoms, age, or other factors. All of these medications can greatly improve motor symptoms and quality of life, but they do not slow the progression of the disease. Treatment may need to be adjusted as the disease progresses.

It is very important to take the medication for motor symptoms at the proper time each day to maximize its effectiveness. Any delay can reduce its effectiveness. Skipping doses can make it difficult to reach or return to optimal function.

Treatment for non-motor symptoms is specific to each symptom and depends on its impact on overall health and quality of life. Some may be relieved by lifestyle changes, while others may require medication.

Surgical procedures are also possible if the disease doesn’t respond well to medication and if the symptoms are severe and very disabling.

Other measures will also help maintain a good quality of life, for example:

• Staying active. An adapted exercise program will help improve balance, muscle endurance, and mobility.
• Eating a healthy diet.
• Learning to manage stress.
• Getting advice from an occupational therapist to make daily activities easier and to reduce the risk of falls.

Seek support

If you or a loved one have Parkinson’s disease, make sure you get support from your family and friends. Many people find that joining a support group helps them cope with the daily challenges of their disease. Across Canada, there are several resources dedicated to helping people with Parkinson’s disease. Do not hesitate to seek their help.

Your pharmacist is here for you!

Your pharmacist will work with you and your healthcare team to optimize your medication to help manage your motor and non-motor symptoms. Do not hesitate to seek their professional advice if you are experiencing side effects or are having difficulty taking your medications as prescribed. 

Always talk to your pharmacist before taking over-the-counter drugs or natural health products, as some can aggravate Parkinson’s symptoms or interact with your medications.