Why COVID-19 patients die from blood clot complications –Haematologists
Severely-ill COVID-19 patients can develop blood clots that can lead to liver failure, kidney failure and blockage of the lungs, haematologists say.
The experts, however, explained that if a patient gets immediate medical attention, the fatality of the clots can be reversed.
Speaking with PUNCH Healthwise in an exclusive interview, Head of Haematology and Blood Transfusion at the Lagos University Teaching Hospital, Idi-Araba, Prof. Sulaimon Akanmu said “the clot reported in patients with COVID-19 is different from the type of clot you and I know about.
“We know about deep vein thrombosis that develops in the veins of the leg and can be complicated by the clot getting detached from the endothelial lining of the veins of the leg.”
According to Prof. Akanmu, if the clot gets detached and travels from the veins of the legs and gets impacted to smaller blood vessels within the lungs, it can cause problems in the lungs, called pulmonary embolism.
“Another clot occurs in the blood vessel that we call arteries and the complication of that is what we call gangrene because it will not allow the artery to take the blood and oxygen to the tissues. The tissue will die of lack of oxygen, otherwise called hypoxic death.
“However, the type of clot that occurs in patients with COVID-19 occurs in the smallest type of blood vessel called the capillary,” Akanmu said.
Akanmu said the mechanism behind this is yet to be fully understood but the proposition is that the SARS-COV2 virus generates many viral proteins that are capable of activating complement protein.
“The end product of complements activation is the deposition of the activated complement, usually referred to as C5b-9 protein on the blood vessel and it happens that this deposition occurs in the capillaries.
“When you have that complement protein getting deposited on the capillary, it is capable of perforating the membrane of the endothelium and cause damage to the cells. When that happens, the protein behind the cells called sub endothelial structures is exposed to the blood flowing within the capillary.
“The sub endothelial structural proteins activate the coagulant protein in the blood and turn this to a clot. The clot in small vessels such as the capillary is referred to as microvascular thrombosis. So COVID-19 causes microvascular thrombosis.
“Microvascular thrombosis occurs only in an individual who has advanced COVID-19 disease,” Akanmu noted.
The don said the most important way of preventing the blood clots is to start treatment of COVID-19 immediately, so that it does not progress to the advanced stage of the disease.
“But if you miss that and you are beginning to see that thrombosis might be happening, then you have to treat microvascular thrombosis, which is the use of anticoagulant.”
Akanmu further said the blood clot becomes dangerous if it happens in the brain, muscles of the heart or capillaries of the lungs.
“If the blood clot happens in the capillaries of the brain, muscles of the heart, it is dangerous or if it happens in the capillaries of the lungs, you will not be able to transfer oxygen from the lungs to the blood and that is fatal.
“However, the majority of people that develop COVID-19 microvascular thrombosis have it on the skin and you see cutaneous patches or rashes. Some of them have been reported to have it in the intestine, lip and many have it in the lungs but if intervention is instituted early, it will not be dangerous.
“When it happens in the liver, it can cause liver failure, if it happens in the lungs, it can cause difficulty in breathing and if it happens in the kidney, it can cause kidney failure.
“Unfortunately, many people with advanced COVID-19 disease also have other comorbidities which worsen the treatment outcome.”
Also, a Senior Lecturer at College of Medicine, University of Lagos and Consultant Haematologist, Dr. Olusola Olowoselu told our correspondent that the severely ill patients of COVID-19 can develop dangerous blot clots because they have comorbidities that predispose them to develop clotting.
“The clotting is referred to as thromboembolic disease or thrombotic disease. Since the majority of those with severe cases have underlying health issues and some might also have a history of thrombotic disease before COVID-19, so the tendency to develop complications is high in COVID-19.
“COVID 19, a viral respiratory illness, is an inflammatory disease that can cause excessive release of inflammatory cytokines. The imbalance release in this clotting proteins will cause the production of abnormal blood clots in the body,” Olowoselu said.
Olowoselu explained further that once a patient has an inflammatory disease, a lot of cascade reaction can take place in which there can be damage to the endothelial lining of the arteries and veins.
“Also sluggishness in the flow of blood can occur as a result of this. When there is a massive release of coagulant proteins in COVID-19 patients, the blood will not flow the way it’s meant to flow and it can predispose the patient to develop blood clots in the lower leg and can also develop in other areas like lungs.
“The complications from the blood clots can lead to the death of the COVID-19 patient because once the clot travels to the lungs, it can block the flow of oxygen to the lungs and the patient can complain of chest pain, shortness of breath and eventually the patient will die if not well-attended to,” Olowoselu said.