La sclérose en plaques: une maladie neurodégénérative qui touche la population canadienne

Philippe Chassé, journalist collaborator and member of the Interest Group in Neurology

Containing beautiful landscapes and possessing a cultural variety that some would consider utopian, Canada is a country of which its population is proud. Courteous, polite and smiling, the Canadian people are reputed for bravely facing the winter with courage and for respecting their fellow citizens.

However, despite the angelic representation one might have, this population is unfortunately at a higher risk of developing certain diseases, particularly with regards to multiple sclerosis (MS), due to its northern geographical location.

What is MS?

Qualified as a chronic autoimmune disease, multiple sclerosis causes, in medical terms, demyelination, which is the collapse of nerve conductors. It can occur randomly throughout the central nervous system (CNS), which is composed of the brain and spinal cord. In short, the patient’s own white blood cells will attack the neurons throughout the entire central nervous system and destroy their ability to communicate with each other.

The cause of multiple sclerosis is still unknown to the scientific world. In fact, not solely linked to the genetics of the affected individual, experts believe that this demyelinating disease could be caused by certain environmental factors, including an infection by the Epstein-Barr virus or a deficiency in vitamin D.

In fact, since vitamin D is synthesized by human skin in contact with UV rays, the lack of it in typical Nordic countries increases the risk of developing the disease among their population. The severity of this nervous disorder could also be influenced by various patient-associated factors, such as active smoking and a high body mass index during adolescence.

Multiple sclerosis employs different immune cells that lead to inflammation of the blood vessels and the alteration of the main cells capable of producing myelin. The latter is the essential component of neurons that ensures rapid and efficient nerve conduction, allowing communication between brain cells. Consequently, the destruction of myelin will affect the transport of nerve information and cause the characteristic plaques of MS.

The Symptoms

As for the symptoms, what explains their origin is, as mentioned earlier, the decrease in nerve conduction. Indeed, due to this loss of efficiency, a healthy patient may suddenly experience certain characteristic symptoms, such as sensory disturbances, fatigue, motor disturbances, and vision problems, for a minimum period of 24 hours.

Three major syndromes explain certain symptoms of MS, namely optic neuritis, which is the demyelination of the eye nerve, incomplete transverse myelitis, which is the demyelination of the spinal cord, and brainstem syndrome, which is the demyelination of the nerves at the junction of the brain and spinal cord. Interested readers are invited to find out more about these three pathologies, as their complexity limits their introduction in this article.

A Sneaky Disease

Thus, after a few weeks of acute symptoms, the majority of them will disappear and the patient will recover to a state of physiological stability, albeit with some remaining handicaps. Parallel to this seemingly stable state, the disease naturally progresses towards accelerated brain atrophy and loss of nerve functions. Therefore, following a few symptomatic and asymptomatic cycles, the death of brain cells will continue on its own, independently of the pathology, and the affected individual will develop increasingly serious cognitive disorders.

Multiple sclerosis is a neurodegenerative disease of crucial importance for the Canadian population. Causing progressive functional loss and inducing long-term disabilities, being affected by it can drastically change a person’s life. Therefore, it is essential for individuals experiencing symptoms resembling this disease to consult a healthcare professional to confirm or rule out the diagnosis in order to start appropriate treatment and avoid major consequences.