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In some people with COVID-19, especially those with a rapid worsening of the infection, a new complication has been observed, consisting of an increased risk of developing diseases caused by clots, such as deep vein thrombosis, stroke or pulmonary embolism.
Although the exact cause of this new complication is not yet known, it is possible that it is related to an exaggerated response of the immune system to fight the new coronavirus, which may end up contributing to the increase in thrombin, which is the protein responsible for blood clotting. That is, when thrombin levels increase, the greater the risk of forming clots, which can end up clogging blood vessels.
Who is most at risk of clots
The formation of clots is a relatively common complication in patients who are bedridden for a long time, especially when there are other associated diseases, such as heart problems or lung diseases. Thus, patients who are hospitalized in ICUs usually already have a higher risk of developing strokes or embolisms. However, in the case of the new coronavirus, this rate of clot formation in ICU patients has been higher.
One of the possible explanations seems to be the development of disseminated intravascular coagulation, which is a condition in which there is the formation of microcoagulants throughout the body and which has been observed in autopsies of some people infected with COVID-19.
In addition, complications from clots have also occurred in some young adults infected with the new coronavirus and who were not admitted to the ICU. In such cases, the increased clot formation has been attributed to an exaggerated response by the immune system to fight the virus.
What causes the exaggerated response of immunity?
The exact cause is not yet known, but it is possible that the overreaction of the immune system may be related to the Macrophage Activation Syndrome, which has been observed in some young adults infected with the new coronavirus. These young adults do not appear to have any other diseases that can aggravate the infection, but they are at an increased risk of developing serious clotting problems, which can end up producing embolisms or strokes.
Macrophage Activation Syndrome is a condition that leads to changes in the cells of the immune system, causing an uncontrolled production of T cells, excessive activation of macrophages and exaggerated release of pro-inflammatory substances. Generally, the diagnosis of this syndrome can be made by assessing the levels of ferritin in the blood, as this is a substance that gets higher in the presence of an increased immune response.
Why does the immune system produce clots?
When the immune system responds in an uncontrolled manner, especially with excessive activation of macrophages, it causes an exaggerated increase in thrombin, which is one of the most important proteins for the blood clotting system.
When thrombin levels increase, there appears to be a greater formation of blood clots. Often, these clots end up clogging only one vessel in the leg, causing deep venous thrombosis, but if they manage to reach the lung, they can cause pulmonary embolism and, if they reach the brain, can lead to the onset of a stroke. Learn how to identify your stroke symptoms and what to do if you suspect.
What can change in the treatment of COVID-19
COVID-19 is a recent disease and, therefore, its treatment is still undergoing small changes over time, especially as many ways of treating and new drugs continue to be tested around the world.
However, given the data on the increase in the number of cases of clot diseases, it is possible that the treatment may include, for some people, the use of anticoagulants, namely heparin, which act by blocking the action of thrombin and, consequently, prevent blood clotting and clot formation. Find out how heparin is used.
In addition, another substance, methotrexate, can also be associated, which is able to control the immune response, preventing it from being too exaggerated, especially in the case of young adults.
Created by: Tua Saúde Editorial Team
Bibliography>
- DR. MAURICIO ESTEBAN GAUNA - DR. JUAN LUIS BERNAVA. Diagnostic and therapeutic recommendations before the Thrombotic Immune Response Associated with Covid-19 (RITAC). 2020. Available at:. Accessed on 27 Apr 2020
- LUSHINA, Nadia et. al .. Pulmonary, Cerebral, and Renal Thromboembolic Disease Associated with COVID-19 Infection. Radiological Society of North America. 2020
- OUDKERK, Matthijs. Diagnosis, Prevention, and Treatment of Thromboembolic Complications in COVID-19. National Institute for Public Health of the Netherlands. 2020