The new coronavirus attack on the body is so complex that it can cause a cascade of unexpected symptoms and complications that can be fatal.
A few weeks ago, neurologists observed that some of their patients were exhibiting symptoms consistent with neurological disorders, including confusion and seizures, while some of their patients were infected with SARS-CoV-2.
And doctors at the Mount Sinai Health System had previously noticed an increase in young patients with stroke symptoms. All tested positive for Covid-19, suggesting that this virus may be the cause of blood clots, which can reach the brain and then block local arteries.
It turns out that this disease does cause increased blood clotting, with tiny clots forming right in the lungs. Now, researchers have finally figured out how it all happened.
Doctors from the Centre for Vascular Biology Ireland (RCSI) and St James's Hospital in Dublin have published a study in the British Journal of Haematology claiming that abnormal blood clotting is a cause of death in critically ill patients with Covid-19.
Microclots form inside the lungs after infection, and the higher the amount of blood clotted, the worse the prognosis.
"Our novel findings demonstrate that Covid-19 is associated with a unique type of blood clotting disorder that is primarily focussed within the lungs and which undoubtedly contributes to the high levels of mortality being seen in patients with Covid-19," said Professor James O'Donnell, Director of the Irish Centre for Vascular Biology, RCSI and Consultant Haematologist in the National Coagulation Centre in St James's Hospital, Dublin.
The team refers to the disease as pulmonary intravascular coagulopathy (PIC), which is different from the diffuse intravascular coagulopathy (DIC) observed with other conditions.
This disease can be the cause of blood clots entering the brain or heart, where they can lead to a stroke or heart attack.
It can also explain the oxygenation problems that appear in severe Covid-19 cases, leading to the need for oxygen therapy and ventilation.
"In addition to pneumonia affecting the small air sacs within the lungs, we are also finding hundreds of small blood clots throughout the lungs. This scenario is not seen with other types of lung infection, and explains why blood oxygen levels fall dramatically in severe Covid-19 infection.
"Further studies will be required to investigate whether different blood thinning treatments may have a role in selected high risk patients in order to reduce the risk of clot formation," Professor O'Donnell said.
The research team also concluded that patients with higher thrombotic activity were more likely to require intensive care.
The new study also suggests that race and ethnicity may have a significant impact on thrombus risk, with Caucasian and African-American patients more likely to develop Covid-19-associated blood clots than Chinese patients.
Caucasian patients are three to four times more likely to have this complication than Chinese patients, the study said. African-American patients are at significantly higher risk, the paper said.
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