June 2 marks the National Day Against Myasthenia Gravis, an autoimmune disease that affects nerve transmission generating muscle weakness and / or fatigue. It is, therefore, a neuromuscular disease suffered by about 15,000 people in Spain and of which every year about 700 new cases are diagnosed.
This fatigue and muscle weakness, characterized by increases during times of activity and decreases with restInitially, it usually appears in a single muscle group: in 50-70% of cases in the ocular muscles, causing double vision or drooping of the eyelids; and 15% to the muscles of the face and throat, generated speech problems, chewing or swallowing problems, among others. In any case, myasthenia gravis can affect any muscle group of voluntary control and, with the passage of time, progress and involve others such as those of the extremities or the respiratory system: this is what is called generalized myasthenia gravis. When a severe weakness of the respiratory and bulbar muscles occurs, called myasthenic crisis, the disease can threaten the life of the patient without mechanical respiratory support.
“An important part of the patients, and thanks to the immunosuppressive and immunomodulatory treatments that we have, will be able to control their disease and even achieve a complete remission of the symptoms. However, around 10% of patients are refracted to first-line immunosuppressive treatments, with which they do not achieve an improvement in their disease, ”says Dr. Alejandro Horga Hernández, Coordinator of the Neuromuscular Diseases Study Group of the Spanish Society of Neurology. “In this group of patients, there can be a higher frequency of myasthenic crises, hospital admissions and emergency care, and the disease has a serious impact on their quality of life. For this reason, it is still necessary to continue research to find new, more specific drugs for the treatment of myasthenia ”.
Myasthenia gravis can show up at any age, although in women its onset is more frequent between 20-40 years and between 60-80 years and in men it is more common to debut after 60 years. In any case, in up to 10-15% of cases the disease can begin in childhood and youth. And it is precisely in under 15 years (due to its relatively low incidence, it may go unnoticed in its initial manifestations) and in elderly people (the symptoms can be attributed to other previous ailments or to aging itself), where more diagnostic delays occur. Currently in Spain, 60% of patients are diagnosed during the first year of experiencing the first symptoms, but in some cases the delay may be more than 3 years.
“Furthermore, in recent years, a growing trend has been observed in the number of diagnoses in Spain. On the one hand, because advances in the knowledge of the disease are allowing our patients to be diagnosed more and better, but also because, for reasons that are still unknown, the incidence of this disease is increasing in Spaniards over 60- 65 years: They account for almost 60% of the new cases diagnosed each year ”, says Dr. Alejandro Horga. “And if we take into account that it is in the elderly population where more diagnostic delays occur, it is important to keep this disease in mind when assessing muscle problems in older people.”
Myasthenia and COVID-19
Due to the ability of SARS-CoV-2 to affect the respiratory system, and since myasthenia gravis can compromise the respiratory muscles, lhe people with myasthenia may be especially vulnerable to this virus, especially those who associated with respiratory problems or those that are treated with immunosuppressive drugs. In any case, and although cases of myasthenia patients who have suffered a worsening of their disease during COVID-19 infection have been reported, fortunately these have not been substantially numerous.
On the other hand, it should be noted that, although some cases of myasthenia have also been reported after having overcome COVID-19 – something to be expected since viral infections can be associated with the development of autoimmune diseases-, this sickness It also doesn’t seem to be an especially common sequel.n in people who have overcome COVID-19.
From the Spanish Society of Neurology it is recommended vaccination against COVID-19 for all those with myasthenia, not only because of its vulnerability, but because none of the vaccines approved to date are contraindicated in patients with neuromuscular diseases, nor is there evidence that neuromuscular disorders increase the risk of side effects. However, and since it remains to be determined whether immunomodulation / immunosuppression treatments decrease the effectiveness of vaccination, it is recommended that After vaccination, patients continue to take precautionary measures, such as the use of masks and social distancing.