A recent research paper provides a better picture of the serious damage that covid-19 can cause throughout the body, not just in the lungs. It highlights heart, kidney, liver, and neurological complications, among others. This long list of symptoms may be the result of direct damage caused by the virus, as well as by a dysfunctional immune system thrown off-kilter by the infection.
The coronavirus that causes covid-19 is usually caught by breathing it in (more uncommonly, people may get it from touching their nose, mouth, or eyes after handling a contaminated surface). From there, the virus tends to infect the upper respiratory tract, often causing symptoms that resemble a typical cold or flu, especially in people with mild illness. In people who develop more serious illness, the virus tends to migrate down to the lungs and lower respiratory tract, causing pneumonia and breathing problems. Many who die from covid-19 often experience a condition called acute respiratory distress syndrome, in which the lungs fill up with fluid and essentially drown the person.
But even milder cases can sometimes cause problems that extend beyond the lungs. The paper, published in Nature Medicine earlier this month, is a review of what we know so far about these “extrapulmonary” symptoms associated with covid-19. It’s based on case studies, reports, and the doctors’ own experiences at the Columbia University Irving Medical Center in New York City during the peak of the city’s epidemic (more than 22,000 NYC residents are known to have died of covid-19 in total, with most deaths reported in April and May).
Some people with covid-19 have developed blood circulation and clotting problems during their illness, the paper notes, leading to an increased risk of heart attack, stroke, and other cardiovascular conditions. There have been reports of new-onset cases of diabetes in some patients, where blood sugar has risen to dangerous levels that need immediate medical treatment. Some people have also developed neurological problems including delirium and hallucinations. Still others develop kidney and/or liver damage, including kidney failure. Covid-19 has also been linked to gastrointestinal symptoms and skin conditions, including prominent lesions and a discoloration of the toes.
“Beyond the life-threatening pulmonary complications of SARS-CoV-2, the widespread organ-specific manifestations of COVID-19 are increasingly being appreciated,” the study authors wrote.
The coronavirus infects our cells through a protein called ACE2. Since many of the cells in our body and various organs have ACE2 receptors, it’s possible that some symptoms are caused by the virus spreading to those affected areas. But scientists are also speculating that much of the harm seen with covid-19 is actually due to the immune system’s destructive response to infection. That probably helps explain why some people continue to report lingering symptoms, even months after the initial infection seems to have resolved.
Understanding how exactly covid-19 makes us sick is crucial to developing new treatments and better helping survivors. One drug that’s shown promise in saving people in critical condition, for instance, is a long-existing steroid called dexamethasone that tamps down the immune system. But it’s likely that we’ll need different types of drugs to prevent cases from becoming serious in the first place, since the immune system is still important to clearing the infection.
One thing that’s clear: The long term effects of the pandemic on global health, beyond deaths alone, are going to be substantial.