From brain fog to migraines to even stroke-like symptoms, neurologists say they are seeing a number of longer-lasting neurological symptoms in patients diagnosed with COVID-19.
Dr. Lakshmi Warrior, chair of neurology at Cook County Health, told NBC 5 "there's a huge spectrum" of what doctors are seeing post-COVID infection.
"Some patients might have some mild symptoms from headaches to what we call brain fog where patients just don't feel like they're thinking as clearly or like back to normal with their thinking and then other patients have more severe symptoms, even stroke and significant nerve damage," she said. "So we're really seeing a pretty wide spectrum of things."
Warrior's comments echo findings from a study from the National Institutes of Health, which reported last year that while COVID is a respiratory disease, "patients often experience neurological problems including headaches, delirium, cognitive dysfunction, dizziness, fatigue, and loss of the sense of smell."
Get Chicago local news, weather forecasts, sports and entertainment stories to your inbox. Sign up for NBC Chicago newsletters.
"The disease may also cause patients to suffer strokes and other neuropathologies," the study found.
Last month, NBC News reported that two recent studies from the California National Primate Research Center and the Rotman Research Institute in Toronto suggest that the virus directly infects neurons in the brain, both of which could in part explain why some patients experience these longer-lasting symptoms.
The NIH study indicates that inflammation could also be a factor.
"We know that COVID enters the nervous system early on and causes a lot of inflammation," she said. "So we think that's where this is coming from."
While Warrior noted that she has seen neurological symptoms across age groups, most commonly, they are seen in those who experience more "severe disease." She said, however, that many younger, healthier patients have reported things like headaches and brain fog following a battle with COVID.
The Centers for Disease Control and Prevention lists brain fog, changes in taste or smell and mood changes among the "post-COVID conditions" reported.
"Unlike some of the other types of post-COVID conditions that tend only to occur in people who have had severe illness, these symptoms can happen to anyone who has had COVID-19, even if the illness was mild, or if they had no initial symptoms," the CDC reports.
Warrior said she's seen such symptoms last anywhere from six months to a year. Most commonly, the longer-lasting symptoms include things like headaches, brain fog and loss of taste or smell. For smell, she said, some patients may never see a return to normal.
"That's not a usual case but we're definitely seeing patients with longer length of symptoms," she said. "So we'll kind of have to watch this and see what happens."
And the problem could be even more extensive than what is already known.
"Because some of these milder symptoms are just things like headache and feeling just a little off... we suspect that the number of patients dealing with this is a lot higher than what we're seeing in the clinic," Warrior said.
The correlation between certain neurological symptoms and severe disease could mean that such conditions could be prevented by vaccination, either by lessening symptoms in breakthrough cases or by preventing the illness altogether, Warrior said.
"I think the number one thing people can do is get vaccinated to protect yourself from these long-term effects," she said. "Especially just avoiding COVID overall."
With concerns surrounding the new omicron COVID variant on the rise, Warrior said that despite the variant potentially causing milder symptoms, it remains unclear how new variants could impact the nervous system.
"These viruses can affect the nervous system in different ways, right?" she said. "So even if it doesn't affect your lungs as much, it can still affect your brain more, so different variants could cause different affects on the brain so that's something that we're watching pretty closely to see if these newer variants have different involvement with the nervous system."
For those who do suffer from long-lasting neurological symptoms, treatment is dependent on the condition.
"For headache, if it's severe enough, people will start treatment and our tension headache treatments and for brain fog there isn't too much more to do," Warrior said. "It's symptomatic overall and we kind of think that over time symptoms should improve."
Still, Warrior urged people to seek medical help "if the symptoms are affecting your daily life."
"The things that we're really concerned about are, you know, some patients develop signs and symptoms of a stroke. So, any sudden onset of numbness, tingling, weakness, vision changes, changes in your speech - those are things that you need to call 911 for right away and seek medical attention," she said.