Since the beginning of the covid-19 pandemic, the list of symptoms and damage caused by Sars-CoV-19 only increases, and already include from acute kidney failure to organ damage and catastrophic blood clots – the new virus attacks not only the lungs , but also blood vessels.
The discovery was made by cardiologist Frank Ruschitzka, head of department at the University Hospital in Zurich, Switzerland. The autopsy of infected people showed small clots and dead cells scattered through the capillaries of the lungs; the blood vessels that carry blood to the rest of the body were distended by widespread inflammation.
This attack on the vascular system would be a second stage in the evolution of the disease, one week after the patient was admitted.
Reports range from a ninefold increase in clots (compared to cases of H1N1 flu) to strokes in healthy young people. This would explain why obese, diabetics and cardiac patients are considered to be at risk: the cells lining their blood vessels are already compromised.
According to Peter Carmeliet, vascular biologist at the Belgian research institute VIB and co-author of an article in Nature Reviews Immunology, “the key is damage to the endothelial cells that line blood vessels, especially in the lungs”.
In the lungs, the attack is brutal. Sars-CoV-19 invades cells in the alveoli; some commit suicide even before the virus reproduces inside. “Cell death is not peaceful; all of its content leaks abroad, ”Nilam Mangalmurti, pulmonary intensivist at the University of Pennsylvania Hospital, told Science Magazine.
Damaged endothelial cells in blood vessels warn others of the attack, and this alert triggers vascular leaks, which flood the alveoli with fluid (characteristic of acute respiratory distress syndrome, or ARDS).
White blood cells migrate en masse to the lungs, and endothelial and immune cells agglutinate even more clotting factors and platelets. More clots form.
These end up blocking the blood supply to all vital organs. The body, trying to react to the invader, triggers a final inflammation process, flooding the tissues with attack cells. At this point, the reaction to covid-19 is out of control, and the patient goes into shock. “The whole process is a vicious cycle,” said Mangalmurti.
It gets worse. “It is reasonable to assume that the virus reaches the brain,” neuroimmunologist Avindra Nath told the French website TrustMyScience. Fainting, seizures and strokes are some of the most serious neurological symptoms reported, in addition to loss of smell and taste, headaches and dizziness. Some patients have developed encephalitis, a potentially fatal brain inflammation.
“We have seen more and more infected victims of strokes, injuries and bleeding in the brain. This would explain why some patients, after going on life support, show signs of serious brain damage to the point that the chance of waking up seems extremely low,” explained intensive vascular neurologist Jenifer Frontera to TrustMyScience.