Coronavirus (Covid-19) and the brain: It’s not just a respiratory illness

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Ten days after testing positive for Covid and a week after her fever subsided this August, Hannah Chambers came down with new symptoms she hadn’t experienced before.

“I felt a little different,” said Chambers, who is 27 and lives in Davenport, Ia. “I was still in quarantine at that time, but when I woke up my hands and my feet on my left side were tingly and numb.”

Chambers’ primary care doctor sent her to the emergency room to rule out a stroke. But after being cleared and sent home, Chambers found she had mounting neurological symptoms.

Hannah Chambers
Hannah Chambers

“The numbness and tingling in my left hand and foot has now increased to full-on muscle zaps and arm tremors,” Chambers said in a phone interview. “I also noticed my fine motor skills had also significantly diminished. Peeling an orange or holding an apple to cut would immediately cause pain to shoot up my arm. I noticed that if I was watching TV at night, my left arm would start to go numb, and there would be times when I would wake up in the middle of the night and it would be completely asleep.”

Chambers, whose only medical condition before getting Covid was high blood pressure that she managed with medication, now struggles daily with exhaustion, confusion and pain so severe that it prevents her from doing household chores.

Chambers is one of a growing number of Covid patients to experience symptoms that continue beyond the two weeks epidemiologists first believed the virus lasted – a group who have dubbed themselves “long-haulers.” Long-haulers, even those whose initial illness was relatively mild, regularly report a wide range of devastating ailments that point to problems throughout the nervous system.

Symptoms so diverse, many didn’t believe it was Covid

Ava McKinney-Taylor, 16, of Stone Mountain, Ga., got sick in early March.
McKinney-Taylor’s illness progressed from fatigue, headache and fever in the early days of her infection to a slew of issues that have changed her life.

“It feels like every month I get a new set of symptoms,” Ava McKinney-Taylor said. “[My school friends] said ‘you’re leveling up!’ Because in July I gained nausea and lack of appetite, and then in September, I gained really heavy, heavy brain fog. Like, I just cannot for the life of me make words and sentences. This month, I’ve gained all kinds of balance problems. Like, I cannot walk through the house without feeling the whole world tilt. So every month I get a new set of things.”

Read more about McKinney-Taylor’s experiences here.

He had multiple sclerosis, but his post-Covid cognitive problems felt different

Fred Joseph, traces his illness back to July, when he noticed an unusual stiffness in his neck. In a matter of weeks, Joseph, who was previously diagnosed with multiple sclerosis, developed extreme fatigue, and migraines so severe they would wake him from sleep.

Joseph, 31, from New York City, also began to suffer from “brain fog,” a catch-all term for cognitive problems including confusion, slowed thought-processing and short-term memory loss.

He said, “I also get that with my [multiple sclerosis], but this felt a little bit different because it took away from my focus.”

Read more about Joseph’s experience here.

Viruses have always caused neurological problems

While it is becoming clearer that the coronavirus affects the nervous system — and not only the respiratory system, as was once thought — the sheer breadth of neurological problems it presents suggest that it can attack the brain and nerves in multiple ways.

Although the mechanisms involved are not entirely clear, the scientific community has long known that viruses have the ability to damage the nervous system.

“We’ve shown over years and years of very meticulous studies how HIV can destroy the brain,” Dr. Avindra Nath, a physician and neuroscientist at the National Institutes of Health who now studies the novel coronavirus, said in a video interview. “[Coronavirus] is HIV on steroids.”

Nath has worked on many of the most famous viral outbreaks of the past 40 years, including Zika and Ebola. He said that while these viruses caused a variety of health issues, each one also left a distinct neurological trail of destruction on the populations it affected. And he said the coronavirus promises to be no different.

“This is your biggest nightmare coming true,” Nath said. “The neurological complications occur early, and they persist.”

Nath said healthcare professionals have seen neurological manifestations of coronavirus in the brain, spinal cord, nerve tissue and muscles. And the range of problems that can erupt is vast, from brain swelling to psychological and cognitive troubles.

“Patients can develop strokes, they can develop mania, they develop psychosis, they can develop cardiovascular collapse,” Nath said.

A familiar diagnosis with an unusual presentation

Lance, who asked that we not use his last name because he felt it would affect his job, came down with Covid in early March.

“I became very, very ill,” Lance, 50 said in a phone interview. “I didn’t know what was going on. And my doctor tested me for flu A, flu B, both were negative, they basically gave me a Z-pak and sent me home. The symptoms, of course, grew worse.”

Then Lance learned that two colleagues who had been visiting from Italy a few weeks earlier had died from Covid after returning home. He got tested right away. It was positive. While infected with Covid, Lance suffered a transient ischemic attack, or a mini-stroke. By the end of April, after he’d already gone back to work, strange new symptoms began to crop up.

“I would have blurred vision sometimes — it’s just something that would come and go. I would be walking sometimes it would be like my left leg would just stop,” Lance said. “I would almost fall because it just would not go and I’m like ‘this is crazy.’”

At first Lance attributed the symptoms to the transient ischemic attack, or TIA.

“I thought O.K., you know, the TIA affected my left side, this is what’s going on. I can adapt, I just need to pay more attention,” he said.

Falling down stairs, mental fog

Soon, his symptoms became more severe.

“I fell down the stairs in my house, just because that leg gave out,” Lance said. “I had kind of a mental fog and my parents became concerned because I was forgetting certain things that I should know, that I should remember without any hesitation.”

He saw a neurologist who put him through a battery of tests.

“My blood counts were way off, which is what led them to do CAT scans and MRIs,” Lance said. “I was having MRIs almost daily for two weeks.”

Eventually, he was diagnosed with Guillain–Barré syndrome, an autoimmune disorder of the nervous system that causes muscle weakness, nerve damage and paralysis. In Lance’s case, the disorder started in his legs and worked its way upwards.

The limits of our understanding

Immune-system mediated conditions like Guillain–Barré are strongly associated with certain viruses, Dr. Nath said. But that doesn’t mean researchers know which neurological conditions to expect from Covid before they see them show up in patients.

“If you’re susceptible to autoimmune [conditions], and I stimulate your immune system, you’re going to develop a garden variety autoimmune disease,” Nath said. “That’s not really happening here.”

Nath said that each virus tends to set off a specific type of immune-response-based neurological damage. And while these types of conditions may underlie many of the neurological problems that long-Covid patients are experiencing, they probably aren’t the only cause.

“What we found, and others have too, is that if you look at the autopsy brain tissues, you’ll find lots of inflammation in the brain,” Nath said. “All the way from the olfactory bulb down to the brainstem, and everything in between.”

Inflammation is not only a sign of infection or tissue damage – it can also interfere with an organ’s normal functioning. And while researchers are not yet sure exactly what caused the inflammation in these deceased patients, Nath said one thing is certain: It’s severe.

Nath said that the blood-brain barrier, a structure of cells in the brain that prevents pathogens in the blood from entering, was broken down. He also found a slew of different cell types associated with severe inflammation and even brain cell breakdown.

“If these patients had survived,” Nath said. “I would be quite certain that they would have ongoing inflammation that will last for months, if not years.”

But beyond observing the effects of coronavirus infection on the brain, Nath said much of the science around treating or preventing this damage is still in process at this point. That’s because the virus is still so new.

“Understanding disease mechanisms becomes hard,” Nath said. “You’re trying to piece it together from little pieces of information here and there. So we can give you some idea of what we think it is, but we don’t know the ins and outs of it quite yet.”

Long-haulers and “brain fog:” it’s all in the nervous system

Serena Santos, 35, of Nampa, Id., also suffered from brain fog as well as problems with vision and balance.

“I don’t think I’m crazy,” Santos said in a phone interview, “but now I’m seeing stuff, I get the brain fog, I lose my balance…it comes and goes.”
Santos has also had other neurological symptoms since contracting Covid in August. She has had two seizures, and has lost 15 pounds as a result of severe nausea.

Read more about Santos’ experience here.

For over two months after he was infected, Andrew Ficker, a 28-year-old web designer in Orlando, Fla., experienced similar symptoms. Besides brain fog and fatigue, he has also experienced numbness in his limbs and occasional auditory hallucinations.

Like many with long-Covid, Ficker never tested positive. This fact, in combination with his neurological symptoms, led doctors to guess that his symptoms might be from a psychiatric condition, and even offered him Xanax.

“I was trying to convince them that I’m not crazy, I’m just sick,” Ficker said.

Read more about Ficker’s experience here.

No real answers, but difficulties persist

Hannah Chambers also struggles with cognitive difficulties.

“There would be days here where I’d have brain fog all day and others when I would have it for only half a day,” she said. “Before Covid, I would be able to sit and draw for hours or read, but nowadays I can’t last for 15 minutes before becoming distracted or tired.”

More than three months after waking up with numbness in her limbs, Chambers still has no coherent explanation for her condition from her doctors. She has had two MRI’s: one of her brain and one of her spinal cord, but the results were normal.

“None of them has really been comfortable putting a label on you know, besides like post-Covid,” Chambers said.

In October, Chambers began working with a rheumatologist. She hopes to find out whether her Covid-induced neurological problems stem from an autoimmune condition.