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How does coronavirus kill? Clinicians trace a ferocious rampage through the body, from brain to toes
What follows is a snapshot of the fast-evolving understanding of how the virus attacks cells around the body, especially in the roughly 5% of patients who become critically ill. Despite the more than 1000 papers now spilling into journals and onto preprint servers every week, a clear picture is elusive, as the virus acts like no pathogen humanity has ever seen. Without larger, prospective controlled studies that are only now being launched, scientists must pull information from small studies and case reports, often published at warp speed and not yet peer reviewed. “We need to keep a very open mind as this phenomenon goes forward,” says Nancy Reau, a liver transplant physician who has been treating COVID-19 patients at Rush University Medical Center. “We are still learning.”
How the virus attacks the heart and blood vessels is a mystery, but dozens of preprints and papers attest that such damage is common. A 25 March paper in JAMA Cardiology documented heart damage in nearly 20% of patients out of 416 hospitalized for COVID-19 in Wuhan, China. In another Wuhan study, 44% of 36 patients admitted to the ICU had arrhythmias.
The disruption seems to extend to the blood itself. Among 184 COVID-19 patients in a Dutch ICU, 38% had blood that clotted abnormally, and almost one-third already had clots, according to a 10 April paper in Thrombosis Research. Blood clots can break apart and land in the lungs, blocking vital arteries—a condition known as pulmonary embolism, which has reportedly killed COVID-19 patients. Clots from arteries can also lodge in the brain, causing stroke. Many patients have “dramatically” high levels of D-dimer, a byproduct of blood clots, says Behnood Bikdeli, a cardiovascular medicine fellow at Columbia University Medical Center.
“The more we look, the more likely it becomes that blood clots are a major player in the disease severity and mortality from COVID-19,” Bikdeli says.
Infection may also lead to blood vessel constriction. Reports are emerging of ischemia in the fingers and toes—a reduction in blood flow that can lead to swollen, painful digits and tissue death.
Re-upping and bolding a line from the intro of the article I linked to at Science:Quote
What follows is a snapshot of the fast-evolving understanding of how the virus attacks cells around the body, especially in the roughly 5% of patients who become critically ill.
I think everyone struggles at least a bit to comprehend the novel coronavirus and its impacts on the human body. The article at Science is a brief reading for OL readers who want to know how close medical sciences are to answers for the questions posed in the article. The questions are almost all ''How?"
Understanding the way the virus works is key to disrupting its work, I think. I thought this article would serve as a reasonably a-political piece to share with OLers. We all seek understanding. The more knowledge, the less fear. I am hopeful that the humans will beat this thing into the ground, if not tomorrow.
I found the most interesting questions were posed on the subject of cytokine storm versus blood system as cause for certain symptoms. Enormous resources are being put in play by the humans to get safe and effective treatments out the door ...Quote
Some clinicians suspect the driving force in many gravely ill patients’ downhill trajectories is a disastrous overreaction of the immune system known as a “cytokine storm,” which other viral infections are known to trigger. Cytokines are chemical signaling molecules that guide a healthy immune response; but in a cytokine storm, levels of certain cytokines soar far beyond what’s needed, and immune cells start to attack healthy tissues. Blood vessels leak, blood pressure drops, clots form, and catastrophic organ failure can ensue.
Some studies have shown elevated levels of these inflammation-inducing cytokines in the blood of hospitalized COVID-19 patients. “The real morbidity and mortality of this disease is probably driven by this out of proportion inflammatory response to the virus,” says Jamie Garfield, a pulmonologist who cares for COVID-19 patients at Temple University Hospital.
But others aren’t convinced. “There seems to have been a quick move to associate COVID-19 with these hyperinflammatory states. I haven’t really seen convincing data that that is the case,” says Joseph Levitt, a pulmonary critical care physician at the Stanford University School of Medicine.
He’s also worried that efforts to dampen a cytokine response could backfire. Several drugs targeting specific cytokines are in clinical trials in COVID-19 patients. But Levitt fears those drugs may suppress the immune response that the body needs to fight off the virus. “There’s a real risk that we allow more viral replication,” Levitt says.
Meanwhile, other scientists are zeroing in on an entirely different organ system that they say is driving some patients’ rapid deterioration: the heart and blood vessels.
One part Science magazine to nine-parts Infowars is a reasonable trade for me ... it's a mean 'flu' that is still in its top killing phase in many of our states and provinces. "Excess deaths" as the actuaries might plot it.
I hope everyone is financially secure and staying safe. Our household has two essential service workers who head out every day and one eighty-year old who is the focus of our 'do not bring it home' efforts. Our governments up here, like yours, are feeding empty wallets with future billions. Canadians are in general much more pacified-by-authority than Americans, and so are doing what public health authorities tell them to do without significant protest.
We have our own gruesome gallows humour on the subject of nursing homes, of course, and the debate on how, where, when and under what criteria we relax the strictures on commerce and recreation. On the other hand, we don't have the ordeal of a presidential election year to get through at the same time.
The biggest losers are the high-cost energy producers. The "demand shock" to the global energy markets is going to be felt for a good while in the Oil Patch, by my estimation.
I will head back to the shallows until I find something as neutrally interesting to share.