Generality
Multiple sclerosis (MS) is a chronic, often debilitating disease that affects the central nervous system (CNS: consisting of brain, spinal cord and optic nerves).
Multiple sclerosis is a disease of the immune system
First of all it is necessary to specify the characteristics of this disease. In multiple sclerosis, the immune system attacks the central nervous system .
It is thought that the disease has a genetic component, which depends on the susceptibility of each individual, and is also influenced by different environmental phenomena. From some researchers the disease is classified as an autoimmune disease, but other specialists do not agree with this definition, since the specific target of multiple sclerosis has not yet been discovered.
Among the parts vulnerable to attack by the immune system, there are first of all myelin, the fatty substance that surrounds and protects the nerve fibers in the central nervous system. In the case of multiple sclerosis, in fact, the myelin is damaged, and consequently also the nerve fibers. The myelin then forms damaged scar tissue (sclerosis), from which the disease takes its name. When any part of the myelin sheath or nerve fiber is damaged or destroyed the nerve impulses that travel to and from the brain and spinal cord are altered, slower or interrupted, and this causes the variety of symptoms that can accompany sclerosis multiple.
Today, most people with multiple sclerosis learn to live with the disease and lead a satisfying life.
The four phases of the disease
People with multiple sclerosis can experience one of the four stages of the disease, each of which may be mild, moderate or severe.
- Relapsing multiple sclerosis with remission : people with this type of multiple sclerosis experience attacks of worsening neurological functions. These attacks, which are called relapses or exacerbations, are followed by partial or complete recovery during the phases of remission, in which the disease does not progress. About 85% of those affected are initially diagnosed with relapsing / remitting multiple sclerosis.
- Primary progressive multiple sclerosis: the course of the disease is characterized by a slow worsening of neurological functions, since the beginning of multiple sclerosis. In this phase, no relapses or remissions can be distinguished. The rate of progression may vary over time, with plateau moments and temporary minor deteriorations. About 10% of people are diagnosed with primary progressive multiple sclerosis.
- Secondary progressive multiple sclerosis: following an initial period of recurrent multiple sclerosis with remission, many people develop the secondary, progressive phase of the disease. At this stage, there is a constant worsening of sclerosis, with more sporadic remissions or plateaus. About 50% of people with relapsing recurrent multiple sclerosis then undergo the progressive secondary phase of the disease within about 10 years. Currently there are no long-term results in which it is possible to determine whether the treatments available today are able to delay this phase.
- Progressive multiple sclerosis with relapses: this phase affects only 5% of individuals who undergo the primary, progressive phase of the disease. In this phase the affected individuals constantly worsen compared to the beginning, with clear attacks of worsening at the level of neurological functions. These people may or may not feel a certain recovery after relapses, but the disease nevertheless continues to progress without remissions.
Possible causes
To date, the causes responsible for the onset of the disease are still uncertain. The researchers argue, however, that a combination of factors may be involved in the onset of multiple sclerosis. Studies are being conducted in the field of immunology (the science that deals with the body's immune system), but also epidemiological and genetic studies, in an attempt to give an answer. Understanding the underlying causes of multiple sclerosis will be crucial to understanding how to treat this disease or how to prevent it.
The possible causes of multiple sclerosis currently include:
- Immunological causes : it is now accepted that multiple sclerosis involves a neurodegenerative process mediated by the immune system (an abnormal response of the body's immune system directed against myelin) at the level of the central nervous system. The exact antigen or target that causes immune cells to respond with an attack remains unknown to date. However, in recent years, researchers have been able to identify: which immune cell prepares the attack, some of the factors that cause cells to attack and some sites, receptors that seem to be "attracted" by myelin to start the process of destruction of the same. Obviously the studies are still ongoing.
- Environmental causes : it is known that multiple sclerosis occurs more frequently in areas far from the equator. Scholars are investigating many factors, including geographical, demographic (age, gender and ethnicity), infections and more, to try to understand the reason for this evidence. It was discovered, for example, that people born in geographical areas called as high risk of developing multiple sclerosis, but who then moved to a geographical area with a lower risk before the age of 15, acquired the risk related to the new area. This suggests that exposure to some environmental factors before puberty would predispose the person to later develop multiple sclerosis. Some scholars argue that this may have to do with vitamin D, which the body normally produces when the skin is exposed to the sun. People who live much closer to the equator are exposed to a great deal of sunlight throughout the year; as a result, they tend to have higher levels of naturally produced vitamin D. It is thought that vitamin D has a beneficial impact on immune functions and this could help protect against autoimmune diseases such as multiple sclerosis.
- Causes due to infections: since exposure to numerous viruses, bacteria and other microbes occurs during adolescence, and since viruses are well recognized as causes of demyelination, it is possible that a virus or infectious agent is the cause of sclerosis multiple.
- Genetic causes: multiple sclerosis is not a hereditary disease in the strict sense of the word, but having a first degree relative, like a parent or sibling, affected by the disease, increases the individual risk of developing it making it many times higher than that of the population general. Studies have shown that there is a higher prevalence of some genes in populations with higher rates of multiple sclerosis. Common genetic factors have also been found in some families where there is more than one affected person. Some researchers hypothesize that multiple sclerosis develops due to a genetic predisposition that leads the immune system to react to some environmental agent that, in case of exposure of the organism, triggers an autoimmune response. In 2016 it was shown that 70% of carriers of a particular mutation in the NR1H3 gene have a rare and severe form of rapidly progressive multiple sclerosis.
Symptoms
To learn more: Multiple Sclerosis Symptoms
In multiple sclerosis, the damage that occurs at the level of the myelin in the central nervous system interferes with the transmission of nerve signals between the brain, spinal cord and other parts of the human body. This alteration of nerve transmission causes the primary symptoms of multiple sclerosis, which vary depending on where the damage occurs.
The most common symptoms include fatigue, which affects around 80% of people. Fatigue can seriously interfere with the activities of the affected person, both at work and at home. You may also experience numbness of the face, body or extremities.
Another symptom of multiple sclerosis is the difficulty in walking and walking.
Another series of symptoms is represented by dysfunctions in the bladder and intestine, from visual disturbances, dizziness, pain, cognitive abnormalities, mood swings, depression and spasticity. These rather common symptoms are sometimes accompanied by other milder and less frequent symptoms, such as speech disorders, hearing problems, tremors and more.
Diagnosis of multiple sclerosis
Currently there are no symptoms or laboratory tests that can determine for themselves if a person is suffering from multiple sclerosis. The doctor generally uses different strategies to check if a person presents the criteria of the guidelines for the diagnosis of multiple sclerosis, which are also important to rule out other possible causes responsible for the symptoms examined. Strategies covered include a careful examination of medical history, a neurological examination and various tests, including magnetic resonance imaging, evoked potentials and spinal fluid analysis.
Treatment of multiple sclerosis
To learn more: Drugs to treat Multiple Sclerosis
Currently there is no cure for multiple sclerosis, but there are drugs approved by the Food and Drug Administration - the US government agency that deals with the regulation of food and pharmaceutical products - that have proven to be able to slow down the course of the disease . Furthermore, many technological and therapeutic advances are able to help those affected by multiple sclerosis to manage the symptoms of the disease. Every year much progress is made in trying to understand the causes of multiple sclerosis in order to find a truly encouraging cure.
Current drugs help reduce the frequency and intensity of attacks that occur in the disease, reduce the accumulation of injuries (damaged areas) in the brain and slow down disability
Among the currently approved drugs are Aubagio, Avonex, Betaferon, Copaxone, Extavia, Gilenya, Novantrone, Rebif, Tecfidera and Tysabri.
Read also: Multiple Sclerosis Diet
