Besides the respiratory issues that leave patients gasping for breath, the virus that causes COVID-19 attacks many organ systems, in some cases causing catastrophic health problems, Reuters reported.

“We thought this was only a respiratory virus. Turns out, it goes after the pancreas. It goes after the heart. It goes after the liver, the brain, the kidney, and other organs. We didn’t appreciate that in the beginning,” said Dr. Eric Topol, a cardiologist, and director of the Scripps Research Translational Institute in La Jolla, California.

In addition to respiratory distress, patients with COVID-19 can experience blood clotting disorders that can lead to strokes and extreme inflammation that attacks multiple organ systems. The virus can also cause neurological complications that range from headache, dizziness, and loss of taste or smell to seizures and confusion.

And recovery can be slow, incomplete, and costly, with a huge impact on the quality of life.

The broad and diverse manifestations of COVID-19 are somewhat unique, said Dr. Sadiya Khan, a cardiologist at Northwestern Medicine in Chicago.

With influenza, people with underlying heart conditions are also at higher risk of complications, Khan said. What is surprising about this virus is the extent of the complications occurring outside the lungs.

Khan believes there will be a huge health care expenditure and burden for individuals who have survived COVID-19.

Patients who were in the intensive care unit or on a ventilator for weeks will need to spend extensive time in rehab to regain mobility and strength.

“It can take up to seven days for every one day that you’re hospitalized to recover that type of strength,” Khan said. “It’s harder the older you are, and you may never get back to the same level of function.”

While much of the focus has been on the minority of patients who experience severe disease, doctors increasingly are looking to the needs of patients who were not sick enough to require hospitalization, but are still suffering months after first becoming infected.

Studies are just getting underway to understand the long-term effects of infection, Jay Butler, deputy director of infectious diseases at the US Centers for Disease Control and Prevention, told reporters in a telephone briefing on Thursday.

“We hear anecdotal reports of people who have persistent fatigue, shortness of breath,” Butler said. “How long that will last is hard to say.”

While coronavirus symptoms typically resolve in two or three weeks, an estimated one in 10 experience prolonged symptoms, Dr. Helen Salisbury of the University of Oxford wrote in the British Medical Journal on Tuesday.

Salisbury said many of her patients have normal chest X-rays and no sign of inflammation, but they are still not back to normal.

“If you previously ran 5k three times a week and now feel breathless after a single flight of stairs, or if you cough incessantly and are too exhausted to return to work, then the fear that you may never regain your previous health is very real,” she wrote.

Dr. Igor Koralnik, chief of neuro-infectious diseases at Northwestern Medicine, reviewed current scientific literature and found about half of patients hospitalized with COVID-19 had neurological complications, such as dizziness, decreased alertness, difficulty concentrating, disorders of smell and taste, seizures, strokes, weakness and muscle pain.

Koralnik, whose findings were published in the Annals of Neurology, has started an outpatient clinic for COVID-19 patients to study whether these neurological problems are temporary or permanent.

Khan sees parallels with HIV, the virus that causes AIDS. Much of the early focus was on deaths.

“In recent years, we’ve been very focused on the cardiovascular complications of HIV survivorship,” Khan said.

At times this is linked to low oxygen levels in their blood, but in certain patients, the confusion appears disproportionate to how their lungs are faring, AFP reported.

Jennifer Frontera, a neurologist at NYU Langone Brooklyn hospital seeing these patients, said the findings were raising concerns about the impact of the coronavirus on the brain and nervous system.

By now, most people are familiar with the respiratory hallmarks of the COVID-19 disease that has infected more than 2.2 million people around the world.

But more unusual signs are surfacing in news reports from the frontlines.

A study published in the Journal of the American Medical Association last week found 36.4 percent of 214 Chinese patients had neurological symptoms ranging from loss of smell and nerve pain to seizures and strokes.

A paper in the New England Journal of Medicine this week examining 58 patients in Strasbourg, France found that more than half were confused or agitated, with brain imaging suggesting inflammation.

“You’ve been hearing that this is a breathing problem, but it also affects what we most care about, the brain,” S. Andrew Josephson, chair of the neurology department at the University of California, San Francisco said.

“If you become confused if you’re having problems thinking, those are reasons to seek medical attention,” he added.

“The old mantra of ‘Don’t come in unless you’re short of breath’ probably doesn’t apply anymore.”

Viruses and brain

It isn’t completely surprising to scientists that SARS-CoV-2 might impact the brain and nervous system since this has been documented in other viruses, including HIV, which can cause cognitive decline if untreated.

Viruses affect the brain in one of two main ways, explained Michel Toledano, a neurologist at Mayo Clinic in Minnesota.

One is by triggering an abnormal immune response known as a cytokine storm that causes inflammation of the brain — called autoimmune encephalitis.

The second is the direct infection of the brain, called viral encephalitis.

How might this happen?

The brain is protected by something called the blood-brain-barrier, which blocks foreign substances but could be breached if compromised.

However, since the loss of smell is a common symptom of the coronavirus, some have hypothesized the nose might be the pathway to the brain.

This remains unproven — and the theory is somewhat undermined by the fact that many patients experiencing anosmia don’t go on to have severe neurological symptoms.

In the case of the novel coronavirus, doctors believe based on the current evidence the neurological impacts are more likely the result of overactive immune response rather than brain invasion.

To prove the latter even happens, the virus must be detected in cerebrospinal fluid.

This has been documented once, in a 24-year-old Japanese man whose case was published in the International Journal of Infectious Disease.

The man developed confusion and seizures, and imaging showed his brain was inflamed. But since this is the only known case so far, and the virus test hasn’t yet been validated for spinal fluid, scientists remain cautious.

More research needed

All of this emphasizes the need for more research.

Frontera, who is also a professor at NYU School of Medicine, is part of an international collaborative research project to standardize data collection.

Her team is documenting striking cases including seizures in COVID-19 patients with no prior history of the episodes, and “unique” new patterns of tiny brain hemorrhages.

One startling finding concerns the case of a man in his fifties whose white matter — the parts of the brain that connect brain cells to each other —  was so severely damaged it “would basically render him in a state of profound brain damage,” she said.

The doctors are stumped and want to tap his spinal fluid for a sample.

Brain imaging and spinal taps are difficult to perform on patients on ventilators, and since most die, the full extent of neurologic injury isn’t yet known.

But neurologists are being called out for the minority of patients who survive being on a ventilator.

“We’re seeing a lot of consults of patients presenting in confusional states,” Rohan Arora, a neurologist at the Long Island Jewish Forest Hills hospital told AFP, saying that describes more than 40 percent of recovered virus patients.

It’s not yet known whether the impairment is long term, and being in the ICU itself can be a disorienting experience as a result of factors including strong medications.

But returning to normal appears to be taking longer than for people who suffer heart failure or stroke, added Arora.