Lung damage in COVID-19 patients compared to those who died of flu

Medical resuscitation service at the Jacques Cartier hospital in Massy. Radio of the lungs of a patient with Covid 19. (Photo by: Pascal Bachelet/BSIP/Universal Images Group via Getty Images)

INDIANAPOLIS (WISH) — The coronavirus swept the globe fast and furiously since the first confirmed case in Wuhan, China, in November 2019. Most COVID-19 attention to date has been on treatment, vaccines and the mechanism by which the virus attacks the body. 

But now scientists are exploring COVID-19 from a different angle in hopes it can help health experts understand the virus even better. Instead of what causes the virus, some experts are interested in the end result when someone dies from the disease. To assess this, researchers are turning to lung autopsies. 

In an article published by the New England Journal of Medicine, researchers assessed seven lungs from patients who died from complications of the coronavirus and compared them to seven lungs from those who died from flu complications. Ten uninfected lungs were also included, but the main goal was to determine if differences existed between the two types of infected lung tissue. 

Authors of the paper, “Pulmonary Vascular Endothelialitis, Thrombosis and Angiogenesis in COVID-19,” used several ways to study the dead tissue including microscopic and three dimensional views of the lungs and associated blood vessels.

Similarities existed between the autopsied flu and COVID-19 lungs. Both had excessive mucus in the small, lower portion of the lungs. Both types of infected lungs also showed excessive immune cells in the blood vessels, which is associated with disease progression. 

However, coronavirus-infected tissue showed additional features, such as blood clotting and bleeding in the blood vessels. The biggest difference, however, was the presence of microthrombi, a type of blood clot that occurs in the smallest blood vessels and is associated with severe respiratory failure. COVID-19 patients were nine times more likely to have these than those who passed from influenza.

In its early stages, COVID-19 was likened to the flu. But mounting evidence continues to indicate there are many more poorly understood associated signs, symptoms and complications of the coronavirus that are not characteristic of the flu. 

Deconstructing and analyzing dead lung tissue, authors say, may pave the way for further evidence to help doctors get a better sense of what additional coronavirus treatments may be needed before these complications happen. 

In addition to the lungs, COVID-19 attacks the heart, liver, pancreas and kidneys and is associated with widespread inflammation throughout the body.