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13 COVID Symptoms That Have Doctors Scared

These are what keep healthcare providers awake at night.

"The more I learn about the virus, the more I would like to not get it," tweeted author Molly Jong-Fast this week. She's not alone. Although doctors have learned much about COVID-19 since the first days of the pandemic, most of what they've learned—particularly about the sheer number of organs the virus can attack—is cause for serious concern, not celebration. The coronavirus can cause symptoms literally from head to toe; they can be both vague and fatal. These are 13 that have doctors mystified, frustrated, even scared. Read on, and to ensure your health and the health of others, don't miss these Sure Signs You've Already Had Coronavirus.


Heart Inflammation

Male patient wearing face mask and feeling chest pain while being at the hospital during coronavirus epidemic

One aspect of COVID that has doctors most worried is that the virus can attack the heart muscle, causing inflammation known as myocarditis. That can lead to a heart attack, damage that's long-lasting or permanent, even heart failure. Up to 7% of deaths from COVID may be due to myocarditis, a recent study found. Scarier still: "Over the past few weeks, the evidence has strengthened that cardiac damage can happen even among people who have never displayed symptoms of coronavirus infection," Scientific American reported on Aug. 31. 


Blood Clotting

Thigh pain or muscle twitching or muscle cramp.

COVID can cause blood clots to form in the body, literally from head to toe. One study found that 20% to 30% of critically ill COVID patients develop clotting, which can prevent oxygenated blood from moving through the body, which can be fatal or necessitate amputation. Doctors aren't yet sure why or how the clotting happens. "We don't yet know if the coronavirus itself stimulates blood clots to form, or if they are a result of an overactive immune response to the virus," says Harvard Medical School. 


Lung Fibrosis

adult male in face mask receiving treatment at hospital suffering respiratory disease lying on bed

Doctors are finding that some of their patients are coming off a case of coronavirus with scarring in their lungs, a.k.a. lung fibrosis. This type of scarring makes it hard to breathe and get adequate oxygen into the body. In minor cases, doctors aren't sure if the scarring is reversible or permanent. Some severe cases have proven to be irreversible—causing even young patients to develop holes in their lungs, requiring a lung transplant.



CT scan of the brain of a patient with intracranial hemorrhage

Another curious, and devastating, feature of COVID-19 is that previously healthy young people with coronavirus but no other risk factors have suffered strokes, some fatal. This seems to be related to COVID's tendency to cause blood clots in the brain (leading to stroke), heart (causing heart attack) and lungs (creating sometimes fatal pulmonary embolisms). 



ECG electrodes on the patient. In hospital

This condition, in which the heart beats irregularly, can be fatal. It can result from COVID-related damage to the heart via myocarditis, an inflammation of the muscle. The risk of a fatal arrhythmia has caused a number of pro and college athletes who've been diagnosed with COVID to bench themselves over the past month. Penn State's director of athletic medicine said on Sept. 3 that 30% to 35% of Big 10 athletes who'd been diagnosed with COVID showed symptoms of myocarditis. "And we really just don't know what to do with it right now," he said.


Trouble Breathing

Doctor nurse in protective face mask listening to breath with a stethoscope suspecting Coronavirus (COVID-19).

Shortness of breath is a common symptom of coronavirus, but serious trouble breathing could be a sign of ARDS (acute respiratory distress syndrome), which can be fatal. It's another symptom that requires immediate medical attention.

According to Harvard Medical School: "There are many examples of temporary shortness of breath that are not worrisome. For example, if you feel very anxious, it's common to get short of breath and then it goes away when you calm down.

"However, if you find that you are ever breathing harder or having trouble getting air each time you exert yourself, you always need to call your doctor.


Neurological Symptoms

Neurology Consultation Woman

In August, a study published in the Lancet found than 55% of people diagnosed with coronavirus still report neurological symptoms three months after their diagnosis. These can include confusion, difficulty concentrating (or brain fog), fatigue, personality changes, headaches, insomnia and loss of taste and/or smell. The researchers warned COVID-19 could end up causing an "epidemic of brain damage," pointing out that precisely that phenomenon occurred after the flu pandemic of 1918.


Elevated Cytokines

Young attractive concentrated female scientist in protective eyeglasses, mask and gloves dropping a red liquid substance into the test tube with a pipette in the scientific chemical laboratory

Another parallel to 1918 is the "cytokine storm." In this phenomenon, the immune system responds to an infection by going into overdrive, producing excessive inflammation (which can cause the heart, lung or kidneys to fail) and blood clots that can be fatal. This was partly responsible for the severity of the 1918 flu, and researchers believe COVID-19 provokes a similar reaction in some cases. According to Harvard Medical School, healthcare providers can test blood cytokine levels to gauge whether this might be occurring, and research is ongoing for effective treatments (steroids like dexamethasone and hydrocortisone have shown promising results so far).


Confusion Or Inability to Wake Up

woman lying on bed at home sick suffering cold flu and temperature covered with blanket feeling unwell and feverish

The CDC recently added "new confusion or inability to arouse" to their list of serious coronavirus symptoms that require emergency medical attention. This can indicate that coronavirus has caused inflammation in the brain.


Skin Changes


According to the COVID Symptom Study, up to 20% of people diagnosed with COVID report their symptoms include skin changes, such as a red, bumpy rash; hives; or irritation resembling chicken pox. These skin issues are so common that some doctors fear there's not enough awareness of a potential red flag: The study's researchers are urging health officials to name skin rashes a fourth key sign of COVID-19 (besides fever, persistent cough and loss of smell).


Fatigue That Won't Go Away


"We're starting to see more and more people who apparently recover from the actual viral part of it, and then weeks later, they feel weak, they feel tired, they feel sluggish, they feel short of breath," said Dr. Anthony Fauci, the nation's top infectious-disease expert, during an interview on Aug. 13. "It's very disturbing, because if this is true for a lot of people, then just recovering from this may not be okay. You may have weeks where you feel not exactly correct."

It's a phenomenon called "long-hauling," and doctors are worried about what it means for the long-term health of the technically recovered. In another interview with Facebook CEO Mark Zuckerberg, Fauci said those symptoms were "similar to myalgic encephalomyelitis and chronic fatigue syndrome. This is not a virus to take lightly, even with young people."


No Symptoms at All Can Be Scary

Friends in the Pub

One of the facets of COVID-19 that has most frustrated doctors and health officials is that up to 40% of people who are infected with coronavirus are asymptomatic—and some may never show symptoms, allowing them to mingle in public and spread the disease unknowingly. It also makes contact tracing (key to stemming any pandemic) difficult or impossible. This asymptomatic spread has doctors especially worried as we head into fall and winter, when Americans spend more time indoors. That's what's behind experts' calls to consistently wear a face mask and to practice social distancing.


Strange and Painful Symptoms That May Last Forever

woman worry about her teeth and look in the mirror.

The long-haulers are reporting everything from costochondritis (a pain in the chest that feels like a heart attack but is actually inflammation) to brain fog (an inability to concentrate), with thrush (tongue rashes) and anxiety and 96 other symptoms in-between. Doctors, mystified and concerned, are sending many to integrative care for acupuncture or psychotherapy because there is no "silver bullet" medication that will help them get their old lives back. The pain and discomfort may be chronic. When the death toll is counted, these patients will still be walking the Earth, but casualties nonetheless.


How to Protect Yourself and Others From COVID-19

As for yourself, do everything you can to prevent getting—and spreading—COVID-19 in the first place: Mask, get tested if you think you have coronavirus, avoid crowds (and bars, and house parties), practice social distancing, only run essential errands, wash your hands regularly, disinfect frequently touched surfaces, and to get through this pandemic at your healthiest, once again don't miss these Sure Signs You've Already Had Coronavirus.

Michael Martin
Michael Martin is a New York City-based writer and editor whose health and lifestyle content has also been published on Beachbody and Openfit. A contributing writer for Eat This, Not That!, he has also been published in New York, Architectural Digest, Interview, and many others. Read more about Michael