In order to keep our cool in the face of a threat, our body relies on the immune system. But faced with the uncontrollable infection of the coronavirus, while the immune system drops cytokines into the lungs without any regulation, this slaughter becomes a general melee or with Rasmussen’s words: “Instead of targeting a target with a rifle, you use a missile. And therein lies the problem: your body no longer targets infected cells, it also attacks healthy tissue.
And the consequences are felt outside the lungs. Cytokine shocks cause inflammation that weakens the pulmonary blood vessels and fluids begin to enter the air sacs. “Simply put, your blood vessels start to bleed,” says Rasmussen. The shock spreads through the circulatory system and creates systemic problems in multiple organs.
From there, the situation can quickly escalate. In some of the more severe cases of COVID-19, the cytokine response associated with a weakened ability to pump oxygen to the rest of the body can cause multiple organ failure. Scientists aren’t sure exactly why some patients have complications outside the lungs, but they could be linked to underlying health conditions like heart disease or diabetes.
“Even if the virus does not directly reach the kidneys, liver, spleen or other systems, it can have serious trickle-down effects on all of these processes,” says Frieman. And that’s where the serious stuff begins.
LIVER: COLLATERAL DAMAGE
When a zoonotic coronavirus spreads from the respiratory system, your liver is often one of the first organs to suffer. Doctors detected signs of liver damage with SARS, MERS and COVID-19. Generally moderate, they sometimes lead to irreversible damage and even liver failure in the most serious cases. But then, what exactly is going on?
“Once a virus has entered your bloodstream, it can swim to any part of your body,” says Lok. “The liver is a very vascular organ, so a coronavirus can easily get into it. “
Your liver works hard to keep your body working properly. Its main function is to process your blood after it has passed through your stomach by filtering out toxins and producing nutrients that your body can then use. It also makes bile, which allows your small intestine to break down fat and contains enzymes that speed up your body’s chemical reactions.
In a healthy body, says Lok, liver cells die permanently and release enzymes into your bloodstream. This resourceful organ quickly regenerates new cells and resumes its activities, imperturbable. Thanks to this regeneration process, the liver is able to take a large number of strokes.
On the other hand, an abnormally high concentration of enzymes in the blood, as has been observed in patients suffering from SARS and MERS, should be read as a warning. It may be a sign of a moderate lesion that the liver can quickly forget or a more serious problem, perhaps even liver failure.
According to Lok, scientists do not yet fully understand how these respiratory viruses behave in the liver. Perhaps the virus directly infects the liver by replicating and then killing the cells itself. Or maybe these cells are just collateral victims of the disproportionate inflammatory reaction caused in the liver by our immune system.
Either way, Lok says liver failure has never been the only cause of death for SARS patients. “Before the liver stops working, you will often have discovered that in addition to the lung and liver problems the patient is suffering from, he also has kidney problems. The infection then became systemic. “
THE KIDNEYS: EVERYTHING IS LINKED
Yes, this infectious chaos also affects your kidneys. During previous epidemics, 6% of SARS patients and 25% of people infected with MERS suffered from acute renal failure. Studies have shown that COVID-19 can cause similar damage. Although this condition remains relatively unusual, it is nonetheless fatal. According to a study published in 2005 in the journal Kidney International, 91.7% of SARS patients with acute renal failure died.
Like the liver, your kidneys filter your blood. Each kidney contains about 800,000 microscopic distillation units called nephrons. These nephrons are mainly made up of two elements: a filter to clean the blood and a small vessel which returns the filtered material towards your body and the rejects towards your bladder in the form of urine.
The kidney tubules seem to be the most affected by these zoonotic coronaviruses. After the SARS epidemic, WHO announced that the virus had been identified in the renal tubules which can subsequently become inflamed.
It is not unusual to detect a virus in the tubules if it is already present in the blood system, says Kar Neng Lai, professor emeritus at the University of Hong Kong and consultant in nephrology for the establishment Hong Kong Sanatorium and Hospital. Since your kidneys are constantly filtering your blood, tubular cells can sometimes retain the virus and cause temporary and moderate damage.
These lesions can become fatal if the virus enters cells and begins to replicate. However, as Lai, who was also part of the group of researchers behind the study published in Kidney International, there was no evidence of replication of the SARS virus in the kidneys.
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