Parkinson’s disease is a disease of the nervous system that affects movement. It develops gradually, sometimes starting with a tremor barely perceptible with one hand. It also causes stiffness or slowing of movement.
The Parkinson’s disease is a degenerative disease which results from the slow and progressive death of neurons in the brain. As the area of the brain affected by the disease plays an important role in the control of our movements, sufferers gradually make rigid gestures , jerky and uncontrollable . For example, bringing a cup to one’s lips with precision and flexibility becomes difficult. Nowadays, available treatments can reduce symptoms and slow down the progression of the disease quite effectively. You can live with Parkinson’s for many years.
Parkinson’s- related disorders most often appear around age 50 at age 70. The average age of onset in Canada and France is 57 years old. In the beginning, the symptoms can be confused with the normal aging of the person but as they get worse, the diagnosis becomes more obvious. At the moment when the first symptoms appear, it is estimated that 60% to 80% of the nerve cells of the substantia nigra (see box) are already destroyed. So when the symptoms appear, the disease already has on average 5 to 10 years of evolution.
Worldwide, the disease is diagnosed in more than 300,000 people each year. The number of cases increases with age. It is estimated that at age 65, one in every 100 people will be affected, and two out of every 100 people would be reached at age 70 and over.
|At the heart of the disease: a dopamine imbalance
The nerve cells affected by Parkinson’s disease are located in an area called “black substance” and located in the midbrain, in the center of the brain. The cells in this area produce dopamine, a chemical messenger (called neurotransmitter) that allows movement control but also acts in the sensation of pleasure and desire. The death of the dark substance cells creates a lack of dopamine, leading to an increase in acetylcholine and glutamate (two other chemical messengers). This imbalance causes the appearance of symptoms of the disease, namely tremors, muscle rigidity and an inability to perform certain movements. Conversely, an excess of dopamine could be at the
Causes of Parkinson’s disease
What causes the progressive loss of neurons in Parkinson’s disease remains unknown in most cases. Scientists agree that a set of genetic and environmental factors intervene, without always being able to define them clearly. According to the current consensus, the environment would play a more important role than heredity, but genetic factors would be predominant when the disease appears before the age of 50. Here are some environmental factors involved:
- Early or prolonged exposure to chemical pollutants or pesticides , including herbicides and insecticides (eg, rotenone );
- The MPTP , a drug sometimes contaminant heroin, can cause a suddenly serious and irreversible form of Parkinson’s. This drug exerts its effect in a manner similar to the pesticide rotenone;
- Poisoning carbon monoxide or manganese .
The researchers also noted that many changes occur in the brains of people with Parkinson’s disease, although the reasons for these changes are not established. These changes include:
- The presence of Lewy bodies, which are substances present in brain cells (neurons). The researchers believe that these Lewy bodies play a toxic role in Parkinson’s disease.
- The presence of alpha-synuclein in Lewy bodies. Although many substances are present in Lewy bodies, scientists believe that alpha-synuclein is a protein that plays a detrimental role when it is in an aggregated form that cannot be dissolved by cells.
Evolution and possible complications
The progression of Parkinson’s disease varies among individuals. Parkinson’s disease is chronic and progressing slowly, which means that symptoms worsen over many years.
- Motor symptoms vary from person to person, as do their progression.
- Some of these symptoms are more troublesome than others depending on what a person normally does during the day.
- Some people with Parkinson’s disease live with less disabling symptoms for many years, while others develop motor difficulties faster.
- Non-motor symptoms also vary from one individual to another and affect most people with Parkinson’s disease, regardless of the stage of the disease. Some people with the disease find that symptoms such as depression or fatigue interfere more with their daily activities than motor problems.
Parkinson’s disease is often accompanied by the following problems that can be treated:
- Difficulties of thought. The onset of cognitive impairment usually occurs in the later stages of the disease. Such cognitive problems do not respond very well to drugs.
- Mood disorders. People with Parkinson’s disease may suffer from depression. Benefiting from a treatment against depression, it is easier to manage other problems of Parkinson’s disease. Other disorders such as anxiety or loss of motivation may accompany depression.
- Swallowing problems. The person has difficulty swallowing as his condition worsens. Saliva can accumulate in the mouth due to slow swallowing.
- Sleeping troubles. People with Parkinson’s disease often have sleep problems. They wake up frequently at night, wake up early, or fall asleep during the day.
- Incontinence. Parkinson’s disease can cause bladder problems, leading to an inability to control urine or difficulty urinating.
- Constipation. Many people with the disease become constipated, mainly due to a slower digestive tract.
- Change in blood pressure, with dizziness or lightheadedness (orthostatic hypotension).
- Odor disorders. Difficulty identifying or differentiating certain odors.
- Tired. Many patients experience fatigue, and the cause is not always known.
- Pain. Many people with the disease suffer from pain, either in specific areas of the body or throughout the body.
- Sexual dysfunction. Some people with the condition report decreased desire or sexual performance.
The symptoms of Parkinson’s disease
Motor-related symptoms often appear asymmetrically, that is, reaching one side of the body and spreading to both sides of the body after a few years.
Most common symptoms
In 70% of cases, the first symptom consists of uncontrollable rhythmic tremors of one hand , then of the head and legs, manifesting itself more particularly at rest or during periods of stress. On the other hand, 25% of the patients do not show any tremor.
NB The tremor that occurs when you lift an object, for example, is not a sign of Parkinson’s.
- A decrease and cessation of tremors when the person is moving and sleeping;
- The stiffness of limbs, slow movements (bradykinesia), rigid and jerky, difficult to initiate. As the disease progresses, it can lead to difficulties in daily tasks such as buttoning clothes, tying shoelaces, taking coins, walking, standing or getting out of a car;
- The parkinsonian approach is characteristic: small steps by dragging the feet, the arched back, with little or no swinging of the arms;
- A loss of olfaction, sleep disturbances, constipation, which may appear early;
- A loss of balance, occurring later in the evolution of the disease.
Other symptoms, as appropriate
- Depression and anxiety
- Difficulty swallowing
- Excessive salivation with difficulty in containing saliva (the person drools);
- A small, very tight writing (micrograph), due to the loss of dexterity;
- A quavering voice, without expression and difficulty in articulating;
- Lack of facial expression, with a decrease or absence of eyelid flutter;
- The presence of dandruff and oily skin in the face;
- Urinary incontinence;
- Confusion, memory loss and other fairly important mental disorders, occurring rather late in the course of the disease;
- Difficult position changes; it can be difficult to get out of bed or chair, for example. And in some cases, it becomes impossible to move.
|Parkinson’s syndrome or Parkinson’s disease?
Symptoms similar to Parkinson’s disease may occur in some people, but the diagnosis of Parkinson’s cannot be made. In fact, Parkinson’s disease represents 85% of the cases of a set of diseases called ” Parkinson’s syndrome “. The latter is also manifested by movement disorders but the physiology of the disease differs. Parkinson’s syndrome is usually caused by an imbalance in the cholinergic system (acetylcholine) rather than a dopamine deficiency. Overall, some differences are visible and the treatment is not the same.
Conditions that can trigger Parkinson’s Syndrome include damage to the brain as a result of trauma or tumor, small strokes, and the use of certain drugs used to treat nausea, epilepsy, hypertension or psychiatric disorders. Various infrequent neurological diseases are also manifested by parkinsonian syndrome.
Diagnostic of Parkinson’s disease
There is no specific test for diagnosing Parkinson’s disease. The neurologist will diagnose the condition based on a person’s medical history, a review of signs and symptoms, and a neurological examination.
The doctor may request tests, such as blood tests, to exclude other conditions that may cause these symptoms.
Imaging tests – such as MRI or a brain scan – can also be used to help eliminate other disorders. Imaging tests are not particularly useful for diagnosing Parkinson’s disease.
In addition to a standard test, your doctor may give the person carbidopa-levodopa, a medicine used to treat Parkinson’s disease. It must be given a sufficient dose for the benefit to be observed, since low doses administered for a day or two are not sufficient. Significant improvement with this medication will often confirm a diagnosis of Parkinson’s disease.
The diagnosis of Parkinson’s disease can take a long time. Physicians may recommend regular follow-ups to assess the condition and symptoms of the person over time and diagnose Parkinson’s disease.
People at risk for Parkinson’s disease
- The disease affects more often people aged 55 and over ;
- The men are more frequently affected than women for reasons unknown;
- A person whose parents have the disease is at higher risk of having the disease themselves. But the genetic contribution would be especially important for those who develop the disease when they are young.
People with Parkinson’s often experience periods of depression. However, researchers are now studying the hypothesis that depression is a predisposing factor for the disease. This remains to be demonstrated. It may be that, for some, it is only an early manifestation of the disease.
Prevention of Parkinson’s disease
There is no recognized way for doctors to prevent Parkinson’s disease. Here is what research indicates.
Men who consume caffeine beverages (coffee, tea, cola) in moderate amounts (1 to 4 cups a day) could benefit from a protective effect against Parkinson’s disease, according to cohort studies. large scale. A study of a population of Chinese origin showed the same effect34. On the other hand, in women, the protective effect has not been demonstrated so clearly. Still, an 18-year cohort study reveals that the risk of Parkinson’s disease is decreasing among coffee consumers who do not take hormone replacement therapy at menopause. Conversely, combined use of replacement hormones and caffeine would increase the risk.
Drinking one to four cups of green tea a day also seems to prevent Parkinson’s disease, an effect that would be due, at least in part, to the presence of caffeine in green tea. In men, the most effective doses range from about 400 mg to about 2.5 g of caffeine a day, a minimum of 5 cups of green tea per day.
In addition, people who are addicted to tobacco are less likely to have Parkinson’s disease. According to a meta-analysis published in 2012, this risk would be reduced by 56% among smokers, compared to those who never smoked. Nicotine stimulates the release of dopamine, offsetting the dopamine deficiency found in patients. However, this benefit does not weigh heavily compared to all the diseases that can cause smoking, including several types of cancer.
Several meta-analyzes indicate that ibuprofen may be associated with a reduced risk of Parkinson’s disease. Data on other nonsteroidal anti-inflammatory drugs (NSAIDs) are contradictory, with some meta-analyzes finding that NSAIDs are associated with a reduced risk of disease while others report no significant association.
Medical treatments for Parkinson’s disease
Although there are no treatments that can cure Parkinson’s disease , it is nevertheless possible to reduce the symptoms by using drugs but also by following certain lifestyle measures . Generally, the symptoms are controlled fairly successfully if the treatment is well adjusted according to the course of the disease. Despite the anxiety and discouragement that the disease can cause, having an active role in caring for it can better live with the decisions that have been made.
Way of life
Stay active. It is very important for the patient to remain active and to exercise. Regular physical activity increases mobility, balance and coordination of the body and helps to combat depression. The doctor may suggest a particular exercise program but any form of physical activity (walking, swimming, gardening, etc.) is beneficial.
Moreover, since people with Parkinson’s disease are more prone to osteoporosis, it is advisable to practice weight-bearing exercises to strengthen the skeleton (weight lifting, walking, jogging, jumps on site, etc.). . Still in the same vein, one must also take a small, regular “dose” of sunlight to counteract a possible lack of vitamin D, a frequent deficiency in Parkinson’s disease. Vitamin D plays a vital role in bone health.
Allow yourself periods of relaxation. Practicing a relaxation technique, such as yoga or tai chi, or resorting to massage therapy is important for reducing stress (see Other Approaches). In people with Parkinson’s disease, stress has the effect of increasing the intensity of tremors.
Prevent falls. As the disease progresses, walking becomes difficult. It is important to buy good shoes – avoid slippery soles – and practice stride by lifting your legs up high. Walking training by a physiotherapist is often recommended. To minimize the risk of falls, the patient ‘s space should be appropriately landscaped . For example, it is better to remove the area rugs, install grab bars near the toilets and bathtub and ramps on the stairs. Occupational therapy assessment is often required.
In order to increase the beneficial action of levodopa (see below), the doctor can make certain dietary recommendations. Consuming the majority of protein at the evening meal and maintaining a carbohydrate / protein ratio of 7 to 1 (7 g of carbohydrate per 1 g of protein), for example, is a favorable measure. According to the Parkinson Society in Quebec (see Sites of Interest), the vegetarian diet naturally offers such a carbohydrate / protein balance. See the page Vegetarianism.
At the Mayo Clinic, it is recommended to have a diet rich in fruits , vegetables and whole grains , which provide natural antioxidants that protect against oxidative damage. These foods are also a good source of dietary fiber, which promotes better intestinal transit. The intake of saturated fat (red meat, dairy products, palm oil and coconut, etc.) should be reduced.
In advanced stages of the disease, chewing becomes difficult: it is important to take small bites. To facilitate swallowing, the more consistent foods can be mixed in the blender before being consumed.
To prevent constipation from Parkinson ‘s disease, doctors recommend drinking at least 1 liter of watera day and eating enough dietary fiber.
The use of a resource person (a psychologist, a psychotherapist, etc.) is often useful, even necessary, to face the test of any chronic illness. Parkinson’s disease can be particularly difficult to deal with because it attacks the biochemistry of the brain – which is often an important source of anxiety. You can also join a support group .
The appropriate time to start a medication depends on several factors (age, lifestyle, severity of symptoms, hobbies, etc.) and will be determined in consultation with the doctor. Prescription drugs are meant to reduce the symptoms of the disease, but do not stop it. Finding the ideal treatment can take time; it is recommended to report to your doctor any new symptoms that appear during the treatment to make the necessary adjustments.
The levodopa or L-dopa, a precursor of dopamine. In the brain, levodopa is converted into dopamine. It is often prescribed in conjunction with carbidopa or benserazide to increase the effects or limit side effects (nausea, vomiting, dizziness upon waking). Levodopa is particularly effective in relieving movement difficulties, tremors and limb stiffness. Since the effectiveness of levodopa decreases over time – it often becomes much less effective after 5 years or 6 years – doctors generally expect the symptoms of the disease to be important before prescribing it.
The agonists of dopamine mimic the effects of dopamine (bromocriptine, pergolide, pramipexole and ropinirole are examples). These drugs can be prescribed as soon as the diagnosis is established and be associated with levodopa when the disease is in an advanced stage. These drugs have side effects similar to levodopa, but they can also cause compulsive behaviors (gambling, hypersexuality, compulsive shopping), in 7 to 13% according to some studies.
Inhibitors of monoamine oxidase B (MAOI B), such as selegiline and rasagiline, may be prescribed at the onset of the disease. They reduce the degradation of natural dopamine and that formed from levodopa. In addition, they prevent the formation of free radicals and neurological toxins, thus protecting healthy cells. This protective effect is not fully demonstrated. This class of medications sometimes causes side effects, such as tremors and confusion. She has many interactions with other drugs and natural health products.
The anticholinergics (benztropine of the trihexyphenidyl) help reduce tremor in some people by restoring the balance between dopamine and acetylcholine in the brain. It is usually prescribed to younger patients in whom tremors are the dominant symptom. This is the oldest type of medication available to patients.
The inhibitors of catechol O-methyltransferase (COMT) prolong the effect of treatment with carbidopa-levodopa by blocking the enzyme that degrades levodopa. Tolcapone is prescribed only to people who do not respond to other therapies because it can lead to liver damage . Entacapone (Comtan) does not cause this problem. It is combined with carbidopa and levodopa in Stalevo. However, it can worsen the side effects of levodopa.
The amantadine , an antiviral drug originally developed to treat influenza , showed beneficial effects for people with Parkinson’s disease. As this drug only slightly reduces the symptoms, it is used in patients who are at an early stage of the disease . Its mechanism of action in the brain is not yet well known. When combined with levodopa, amantadine may help reduce motor problems in the advanced stagesof the disease.
Note. Levodopa and dopamine agonists can cause the drowsiness during the day. Vigilance is required since some patients treated with these drugs may experience drowsiness in full activity (for example, driving a car).
In addition to drugs used to reduce motor disorders, an antidepressant is sometimes prescribed. Several factors can lead to depressive illness in the patient: having to live with a chronic degenerative disease, the usual tasks that become progressively more difficult, the physiological changes that take place in the brain during the illness and the side effects of certain medications .
For patients with advanced disease whose symptoms no longer respond stably to levodopa, brain surgery may be considered.
The deep brain stimulation involves the implantation of electrodes into specific parts of the brain (thalamus, globus pallidus or subthalamus). A stimulator then sends electrical pulses to reduce involuntary movements and tremors. However, this procedure does not decrease muscle stiffness, does not correct the loss of voluntary movement and involve some risk of side effects serious.
Previously, there were small lesions in the cerebral portion responsible for Parkinson’s symptoms: pallidotomy (pallidum), thalamotomy (thalamus), or sub-thalamotomy (subthalamic nucleus). These very delicate surgeries of the brain are today very rarely used.
Physiotherapy and speech therapy
The physiotherapy includes daily physical exercise, gymnastics, training for walking, working postural balance, etc. is an important therapeutic supplement. The occupational therapy is indicated for functional rehabilitation and home adaptations. The speech allows the management of dysarthria, disorder expressive language had a tough joint.
Various novel treatments, such as fetal dopaminergic cell transplantation and gene therapy, are being studied, but they are experimental treatments none of which is commonly practiced.