July 14, 2020

What dozens of Covid-19 patient autopsies have revealed about the disease

Daily Briefing

    Experts across the United States have performed dozens of autopsies on patients who died from Covid-19, and their findings could have a significant impact on how health care providers treat patients with the disease.

    It's not just lungs: Covid-19 may damage the heart, brain, and kidneys

    According to the Washington Post, at the start of America's new coronavirus epidemic, hospitals at the were too overwhelmed  with trying to save the lives of patients with Covid-19, the disease caused by the virus, to spend much time conducting autopsies. However, by late May and June, researchers from about six institutions published the first large batch of reports on autopsies of Covid-19 patients, which confirmed some early ideas on how the disease worked, debunked others, and raised new questions about Covid-19.

    Blood clots 'in almost every organ'

    According to Amy Rapkiewicz, chair of the department of pathology at NYU Langone Medical Center, autopsies have confirmed the damage to patients' lungs, kidneys, and livers that physicians have been reporting since the epidemic's start. However, she said the autopsies also revealed something unexpected: Some Covid-19 patients developed blood clotting issues to a "dramatic" extent.

    At the start of the Covid-19 epidemic, some clinicians had noted that some patients with the disease were experiencing a lot of blood clotting "in lines and various large vessels," Rapkiewicz said. But "[w]hat we saw at autopsy was sort of an extension of that," she said.

    Rapkiewicz explained, "The clotting was not only in the large vessels but also in the smaller vessels. And this was dramatic, because though we might have expected it in the lungs, we found it in almost every organ that we looked at in our autopsy study."

    Rapkiewicz's findings, published in the Lancet's eClinicalMedicine, suggest that these clotting patterns may be a primary cause of multiple-organ failure among patients with Covid-19, the Post reports.

    'Microclots' in the lungs

    According to the Post, the recent reports have largely confirmed that the novel coronavirus attacks victims' lungs "the most ferociously." For instance, in one of the first published autopsies of a Covid-19 patient, which was published on April 10, Richard Vander Heide said he found hundreds or thousands of microclots in the lungs of a 44-year-old man who had been treated at LSU Health.

    "I will never forget the day," Vander Heide, who's been performing autopsies for more than 20 years, said. "I had never seen something like this."

    But as Vander Heide examined other patients, he noticed the same pattern of clotting in the lungs. Vander Heide said he was so alarmed by his findings that he shared his research online before it was submitted to a journal, so that doctors could immediately review it. Those findings—eventually published in the Lancet—influenced a number of doctors to give blood thinners to Covid-19 patients, which is now a common practice, the Post reports.

    Other autopsies of Covid-19 patients—including autopsies on patients in Italy and others conducted by Mount Sinai researchers—have found similar patterns of microclots in the lungs.

    Megakaryocytes in the heart

    Recent research seems to debunk one concern about Covid-19, however. Early reports from China on Covid-19 patients said up to 20% to 30% of patients seemed to have myocarditis, a thickening of the heart muscle that makes it unable to efficiently pump, which could cause sudden death.

    But the recent spate of studies published based on patient autopsies have found little evidence of myocarditis in Covid-19 patients. Mary Fowkes, an associate professor of pathology who has performed autopsies on 67 Covid-19 patients at Mount Sinai Health, said while she and her colleague Clare Bryce found "very mild" inflammation on the surface of the heart, there was nothing to suggest the patients had myocarditis.

    However, Rapkiewicz, who has studied the hearts of seven Covid-19 patients, found something else unusual: The presence of rare cells called megakaryocytes in the hearts. These cells produce platelets used to control clotting and are usually only found in the bone marrow and lungs.

    "I could not remember a case before where we saw that," Rapkiewicz said. "It was remarkable they were in the heart."

    Significant brain damage

    Researchers also discovered some unexpected findings in patients' brains, the Post reports.

    In March, a study from China published in the BMJ's Journal of Neurology, Neurosurgery & Psychiatry found that 22% of 113 Covid-19 patients studied had neurological problems ranging anywhere from excessive sleepiness to coma. And in June, other research from France found that 84% of Covid-19 patients in intensive care had neurological symptoms, the Post reports.

    As a result of such reports, Isaac Solomon, a neuropathologist at Brigham and Women's Hospital, wanted to determine where the new coronavirus embedded itself in the brain. However, Solomon found bits of the virus only in some areas of the brain and just a few small pockets of inflammation. And it wasn't clear whether the pieces of coronavirus that Solomon found in the brains were dead remnants of the virus or if they had been active when the patients died.

    But Solomon noticed a lot of brain damage as a result of oxygen deprivation—no matter if the patient examined was a longtime ICU patient or a person who died very suddenly of Covid-19.

    Solomon said his research underscores the need to put people on supplementary oxygen to prevent irreversible damage to the brain. It also suggests brain damage resulting from the coronavirus occurs over a long period of time, which made Solomon curious about how the virus might affect the brains of those with mild cases of Covid-19.

    "The big lingering question is what happens to people who survive Covid[-19]?" he said. "Is there a lingering effect on the brain?"

    Similarly, the scientists from Mount Sinai looked at 20 brains and found little inflammation or virus presence. However, they did find a "striking" presence of small clots. "If you have one blood clot in the brain, we see that all the time," Fowkes said. "But what we're seeing is, some patients are having multiple strokes in blood vessels that are in two or even three different territories."

    Takeaways

    Overall, Rapkiewicz said it's too soon to know what autopsy findings mean for treatment of Covid-19, but she added that the research has given scientists new things to explore.

    Jeffrey Berger, a cardiac specialist at NYU, said the autopsy research suggests that providers should prescribe anti-platelet medications alongside blood thinners to Covid-19 patients.

    "It's only one piece of a very big puzzle, and we have a lot more to learn," he said. "But if we can prevent significant complications and if more patients can survive the infection, that changes everything" (Ellis/Kane, CNN, 7/10; Cha, Washington Post, 7/1; Vaidya, Becker's Hospital Review, 7/8).

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