Why does COVID-19 cause brain fog?
As we’ve learned from more than a year of dealing with COVID-19, the symptoms and side effects vary from person to person. Because COVID-19 is a respiratory virus, some symptoms, like chest pains and coughing, are to be expected. But others, like brain fog, are more puzzling. Many people who have recovered from COVID-19 have reported feeling not like themselves: experiencing short-term memory loss, confusion, an inability to concentrate, and just feeling differently than they did before contracting the infection.
Here is what we know—and don’t yet know—when it comes to brain fog and COVID-19.
Q: Who is most likely to experience brain fog from COVID-19?
A: We aren’t sure. We expect some neurological issues in those who are severely sick, who have had a major stroke or a traumatic injury, or who have undergone anesthesia for long periods of time, but people who have mild cases of COVID-19—who don’t require hospital visits—are also experiencing neurological side effects from the virus, which is unexpected.
Q: How many people who contract COVID-19 will experience brain fog?
A: At this point, it seems like a third of patients will have some type of neurological illness associated with COVID-19. But this includes a spectrum of issues: memory issues, brain fog, seizures, strokes, and neuropathy (or numbness in the extremities, usually hands and feet). We don’t have solid evidence yet that this is the exact percentage of COVID-19 patients who will experience brain fog.
Most of the information we have now deals with patients who have been to the doctor. We don’t have a lot of information about people who experience COVID-19 brain fog who haven’t seen a doctor. And to understand this better, all types of cases have to be studied—we still have to do large-scale, community-based studies.
Q: Why does COVID-19 cause neurological symptoms?
A: Preliminary data shows that COVID-19 is neuro-invasive, meaning the virus itself can invade the brain and nearby nerves. Something as simple as loss of smell, which is a symptom of COVID-19, indicates a neuro invasion because the nerves that are responsible for smell are in direct connection with brain.
And we’ve seen cases of encephalitis, or inflammation of the brain, caused by COVID-19. The virus can induce a large-scale immune response and that immune response can cause a cytokine storm, which is an excessive mobilization of the immune system. It destroys cells and causes damage to other organs like the brain, liver, kidneys and heart.
Q: Could there also be psychological reasons as to why COVID-19 causes neurological issues?
A: Yes. A COVID-19 infection has expectations of being a severe disease, so it’s a major traumatic event, especially if a patient needs to stay in the hospital and doesn’t have loved ones nearby to comfort them. This is especially so if the patient is intubated or has a near-death experience.
This experience can cause post-traumatic stress disorder (PTSD). The symptoms we see in these COVID-19 patients are similar to those we see in PTSD survivors—they have confusion, memory loss, anxiety or depression.
Q: How long do neurological symptoms from COVID-19 last?
A: Brain fog in COVID-19 is still being studied, but with other critical conditions that affect the brain, we know that a third of people will have complete recovery with no issues. Roughly another third will have lingering effects that improve after therapy and time, and then another third may have permanent effects, especially in cases where the patient has been intubated, has had multiple organ failure or has been under anesthesia for a while.
If someone is going to improve, they should improve within 3 to 6 months after recovering from the infection. If they don’t recover within 6 to 12 months, it’s likely that they’ll be dealing with this life long.
Q: Is it possible to predict how severe someone’s case of brain fog from COVID-19 will be?
A: It depends upon someone’s brain reserve and the severity of illness. Young people who are in good health have higher brain reserves. A healthy 20- or 30-year-old brain has lots of healthy brain cells that can take over the slack and allow the brain to recover. But a 60- or 70-year-old-brain that has had a previous brain injury (such as a stroke or brain tumor) has lower brain reserves and is more likely to feel long-term neurological effects.
Severity of illness is also important. If you have a mild case, you might have a bit of brain fog and recover, but if you have a severe illness, the chances are higher that you’ll have a more permanent outcome.
Q: If someone is experiencing neurological symptoms from COVID-19, what should they do?
A: Recognize and record your symptoms: Write down how severe they are and how they are impacting your life. Bring this list to a doctor who can help diagnose your problem and help you recover with cognitive therapy.
It’s also important to treat any underlying psychological illness. Untreated anxiety, depression or PTSD can affect memory function, so if you put COVID-19 into mix, neurological problems can become inflated.
It’s also always essential to control blood pressure, diabetes—any other underlying health issues you may have. Avoid smoking and alcohol, eat a healthy diet, get enough rest. All of these things will create a nourishing environment for the brain to recover.
Dr. Omar Danoun, M.D., is a neurologist with Henry Ford Health System. He sees patients at Henry Ford Hospital in Detroit and Henry Ford Medical Center in Taylor.