COVID-19, is lurking around the world and still many countries including India are witnessing a sharp rise in positive cases, primarily affecting the upper respiratory tract and the lungs. While the vast majority of affected individuals overcome the infectious disease triggered by the SARS-CoV-2 strain of coronavirus, it unfortunately also has a global death rate of between 2 to 3 per cent of total afflicted people. Moreover, in several situations wherein people have succumbed to coronavirus infection, doctors have reported not only rapidly decreasing oxygen levels and impaired lungs, but the decline of various other organs such as the heart, liver and kidneys as well. Healthcare experts and scientists have identified a key attribute in these fatal instances of COVID-19, often accompanied by multiple organ failure, to be an inflammatory reaction known as a cytokine storm.
What Is A Cytokine Storm?
Cytokines are essentially proteins produced by diverse kinds of cells in all parts of the body, which possess the capability of cell proliferation, immune system activation and inflammatory effects. When the SARS-CoV-2 viral particles invade the human system, a normal immune and inflammatory response occurs, which causes increased amounts of blood containing cytokines to flow to the site of infection, to aid in defence mechanism and thwarting coronavirus disease.
However, during a cytokine storm, there is an overproduction of cytokines that travel to the infected tissues, leading to abnormal immune system activity and subsequently maiming the organs. Although cytokine storms are generally associated with autoimmune disorders like juvenile arthritis and lupus, they are also known to take place in cancer treatment procedures and viral illnesses of flu or influenza.
Cytokine Storm In COVID-19 And Damage To Internal Organs:
A particular phenomenon associated with cytokine storm termed Acute Respiratory Distress Syndrome (ARDS) induces irreversible damage to the lungs and is the reason for a fraction of deaths in patients who test positive for COVID-19. ARDS was recorded in previous epidemics triggered by viral vectors SARS-CoV and MERS-CoV, which also belong to the coronavirus family and instigate maladies of Severe Acute Respiratory Syndrome (SARS) and Middle East Respiratory Syndrome (MERS).
Several research studies have established the specific pro-inflammatory cytokine proteins linked with individuals who test positive for COVID-19 to be interferon IFN-g, interleukins IL1-B, IL-2, IL-6 and chemokines. When a cytokine storm and ARDS happens in coronavirus infected patients, these components induce detrimental effects on the alveoli, capillary membrane in the lungs. This raises the permeability in pulmonary tissues, causing accumulation of fluids and edema, eventually resulting in oxygen insufficiency and respiratory failure.
The instance of ARDS prompted by a cytokine storm is not only a hallmark of inflammation and immune response in COVID-19 but is also observed in pneumonia, sepsis and pancreatitis. Furthermore, since the SARS-CoV-2 strain of coronavirus replicates at a very fast pace upon entering the host i.e. human body, the damage caused by a cytokine storm sometimes occurs in other internal organs besides the lungs, such as the heart, kidneys, liver, eventually resulting in multiple organ failure.
Doctors have deduced that detecting high levels of inflammatory markers i.e. cytokines in corona positive cases in the early stages and administering appropriate anti-inflammatory therapies will avert a decline in the functioning of the lungs and other organs, as well as help patients gradually recover well from COVID-19.