What is multiple sclerosis?

THE May 30, 2023 is World Multiple Sclerosis Day.. A disease whose name we know but not always the definition, treatments and evolution. This disease chronic and disabling occurs in the majority of cases in young adults, around 30 years old, and touch 115,000 people in France including 500 children. 4,000 to 5,000 new cases per year are diagnosed in France. 3 out of 4 patients are women. “Neither the cause nor the cure are currently known” reminds the Foundation Arsep who works for research on this disease.

Definition: what is multiple sclerosis?

There multiple sclerosis (MS) East an inflammatory disease which affects the brain and spinal cord. It is one of the autoimmune diseases characterized by “A dysfunction of the immune system, which attacks the body instead of defending it“, explains Dr. Alexandre Morin, neurologist at Pitié-Salpêtrière (Paris). In the case of multiple sclerosis, the immune system attacks its own central nervous system one of whose roles is to transmit remote information (nerve impulses) to the rest of the body. There is a inflammatory reaction developed against myelin (kind of sheath which surrounds the nerves) to destroy it and which deteriorates the quality of nerve impulses. Damaged areas of myelin cause the characteristic “plaques” of the disease. The disease most often evolves in flare-ups, but can also manifest itself more gradually. Ultimately, she is responsible disability to varying degrees.

What are the causes of multiple sclerosis?

“We observe from many dysfunctions of the immune system, but not major influencing factors. Nothing can prevent multiple sclerosis“, explains Dr. Morin. genetic factor has been detected“To not to be confused with heredity : the fact of having family history of MS does not increase risk for himself. But being a carrier of a combination of certain genes could favor the development of the disease“, he specifies. environmental factors have been identified, such as the lack of vitamin D intake. “This explains the higher prevalence in Western countries, especially in Northern Europe.“, adds the neurologist.

What is a relapse in multiple sclerosis?

A flare corresponds to the acute and rapid onset or aggravation of one or more symptoms of the disease, apart from any feverish episode and over more than 24 hours.

“There is nothing to prevent multiple sclerosis”

At what age do the first symptoms appear?

Multiple sclerosis is the most common non-traumatic neurological pathology of the central nervous system. more commonly seen in young adults. In 70% of cases, it begins between 25 and 35 years old. The average age of onset of symptoms is 30 years.

The first signs usually appear between the ages of 20 and 40. Symptoms are unpredictable and vary from person to person since the expression of the disease depends on the area of ​​the nervous system affected. Involvement of the myelin sheath can occur in many cerebral or spinal areas. The symptomatology of MS includes suggestive signs (visual, balance, speech disorders…) and others less visible general signs or less specific (fatigue, depressive disorders, anxiety, etc.). In half of the cases, the onset is polysymptomatic, that is to say with several symptoms.

The most common symptoms encountered are disturbances of walking, vision, coordination of gestures, speech, urinary disorders. These neurological disorders can appear in flare-ups, which set in within a few hours, last for at least 24 hours, several days or weeks and then completely or partially disappear. During a push, new symptoms may appear, but also the reappearance of old manifestations. In summary, the symptoms of MS can be:

• of the tingling in the armslegs or face,
• balance disorders
• a neuritis optical
• transit and urinary disorders
• of the memory problems and caring
• anxiety and depression

What tests can diagnose multiple sclerosis?

There is no biological test to confirm the diagnosis of multiple sclerosis. It is thus based on several clinical examinations, including cerebral MRI and medullary MRI (of the spinal cord). “In the image, we see appearing white spots which correspond to hypersignals and inflammation of the myelin“, explains Dr. Morin. MS lesions are often multiple and affect both cerebral hemispheres. They are often asymmetrical and their size varies from a few millimeters to a few centimeters.

Evolution: can MS be cured?

There is no cure for MS, but the onset of the most debilitating symptoms can be delayed. Confirming the diagnosis of MS early allows for rapid treatment. However, the early treatment of a first isolated attack can prevent or delay the appearance of other more disabling attacks. “For a long time there was no treatment and disabling symptoms came after 5-10 years. Today, these symptoms occur on average after 20 years and the onset is still delayed.“, says the expert.

What are the treatments for multiple sclerosis?

“Treatments evolve a lot, with the appearance every year of new molecules on the market”, says the neurologist. The treatments aim to reduce the intensity of the symptoms and to space out the flare-ups. Of the immunomodulators are prescribed in the first line in order to regulate the immune activity at the cerebral level. THE immunosuppressants are prescribed in very active forms of the disease or in the event of failure of treatment with an immunomodulator. They act directly on immune cells. Close monitoring is required due to the risk of side effects. “Therapeutic education is also part of the treatment. There MS is a chronic disease that often affects young people, who will have to live with it all their lives. These workshops teach patients how to live well with their pathology. It should be noted that the life expectancy of these patients is similar to that of the general population.“, concludes the neurologist.

Thanks to Dr Alexandre Morin, neurologist at Pitié-Salpêtrière (Paris). Comments collected in 2019.