13 August 2020 Author : Inês Brás Marques In multiple sclerosis , the normal spread of nerve impulses is affected. In this disease, there is an injury to myelin , a protein that surrounds axons of nerve cells and that has an important role in the propagation of those impulses. In the affected nerves, the propagation of nerve impulses is compromised. Multiple sclerosis is the most common nervous system disease in young adults and is more common in women. Symptoms usually begin between the ages of 20 and 40. The disease can take two forms : In most cases (about 80%), multiple sclerosis has episodes of neurological worsening, called outbreaks, and periods without symptoms (remission). This form of the disease is called outbreak-remission multiple sclerosis. Less often, multiple sclerosis can present with progressive and continuous neurological worsening over time. This form is called primary progressive multiple sclerosis. What is the cause of multiple sclerosis? Multiple sclerosis is an autoimmune disease . In these diseases, the immune system (the body defense system) attacks the body own cells, which is called an autoimmune response. In multiple sclerosis, the autoimmune response is directed to the brain and spinal cord , more specifically to the myelin layer that lines the axons of many neurons. It is not exactly known what triggers this abnormal immune system response. However, it is thought that it results from the combination of genetic and environmental factors, such as certain viral infections. What are the symptoms and how is the diagnosis made? The symptoms of multiple sclerosis can affect any part of the body and vary from person to person. The most common initial symptoms are: Changes in sensitivity (tingling, numbness); Decreased strength of the legs or arms; Difficulty walking, imbalance; Vision changes (pain in the eye, decreased vision, double vision); Urinary changes (difficulty in controlling the bladder). Along the course of the disease, other symptoms may occur, such as fatigue (tiredness) and cognitive difficulties. Usually the symptoms worsen over one to two weeks, followed by a gradual recovery, which can be complete or partial. The diagnosis of multiple sclerosis is based on the symptoms and clinical changes characteristic of this disease and on the results of diagnostic tests. Classically, the diagnosis was made when a person suffered two episodes (outbreaks) separated in time, with symptoms related to different parts of the nervous system. Currently, it can be done earlier, if after the first outbreak there are changes in the tests that allow the diagnosis. What tests are useful for diagnosis: Brain and spinal magnetic resonance imaging : obtains detailed images of the brain and spinal cord identifying the characteristic lesions of multiple sclerosis. It may be necessary to administer a contrast product (gadolinium) intravenously to check whether the lesions have active inflammation. Lumbar puncture : a small amount of cerebrospinal fluid is obtained using a needle that is inserted between the vertebrae in the lumbar region to the place where this fluid circulates around the spinal cord. The analysis of cerebrospinal fluid allows to identify changes that suggest the diagnosis of multiple sclerosis and rule out other possible causes for neurological symptoms. Evoked potentials : These tests use small electrodes that are adapted on the head to monitor brain activity in response to visual or auditory stimuli. How multiple sclerosis is treated In multiple sclerosis there are two types of treatments : Treatment of outbreaks Multiple sclerosis outbreaks are treated with corticosteroids given intravenously. Corticosteroids are potent anti-inflammatory drugs, with a rapid effect in improving symptoms. Treatment usually lasts 3 to 5 days and side effects are rare. Preventive treatment These treatments are made with so-called disease-modifying drugs and are chronic treatments , that is, to be done continuously over long periods. They aim to reduce the response of the immune system and thus reduce the autoimmune response and the likelihood of outbreaks. There are currently several drugs available, to be administered in various ways, for example in tablets, subcutaneous or intramuscular injections and intravenous treatments. There are medicines that can be taken at home, and others that are made in the hospital. The choice of medication depends on several factors, including the severity of the disease, the possible adverse effects, and the personal options. Living with multiple sclerosis Multiple sclerosis is a nervous system disease more common in young adults. With proper care it is possible to have an active and healthy life. Multiple sclerosis usually does not reduce average life expectancy. The drugs currently used in the treatment help to prevent new outbreaks, decreasing the occurrence of new symptoms and the accumulation of neurological changes over time. It is possible to be months or several years without new outbreaks. However, it is a very variable disease and the evolution is different from person to person , being necessary to adjust the treatment to each case. During the follow-up of patients with multiple sclerosis, it is common to involve several medical specialties depending on the symptoms (for example, physical medicine and rehabilitation, urology, ophthalmology, psychiatry, among others) and also areas such as psychology and nutrition. Diagnostic tests are performed periodically to assess the evolution of the disease. Multiple sclerosis and pregnancy Women with multiple sclerosis can become pregnant . Pregnancy planning, involving the obstetrician and neurologist, is recommended. Some drugs used to treat multiple sclerosis can be used in pregnancy, if necessary. In cases where the disease is well controlled, it may be considered to temporarily suspend treatment during pregnancy. The content published in the Health Guide is intended for the general public and is provided for informational and educational purposes only. It does not replace individual medical assessment, diagnosis, or personalized clinical advice from a qualified healthcare professional. The content is produced or reviewed by physicians and other healthcare professionals at Hospital da Luz and is based on the knowledge available at the time of publication or the most recent update, as indicated at the beginning of each item.
