“They said it was like marshmallows”. How COVID-19 changes the brain? The doctor explains

Complications after COVID-19 are attracting more and more attention from scientists and doctors. Recent discoveries show that most people complain of disorders in the nervous system. It is not only about the brain, but also the spinal cord and nerves. It has already been mentioned about the so-called neurocovidae or even coronavirus neuroinvasion. How does the coronavirus affect the nervous system, what are the symptoms and what can it lead to? Olga Milczarek, a neurologist, MD, explained. She also told us about her case.

1. Postovid invasion of the central nervous system may affect up to 70 percent. patients
2. In the case of SARS-CoV-2, the body’s defense response is much more rapid than in other viruses. Dr. Milczarek: This shows how difficult and toxic this pathogen is
3. Patients with neurocovid complaints, inter alia, to sleep problems, restless legs syndrome, changes in sensation, including pain sensation
4. The effects of the coronavirus on the brain may also include depression, anxiety, behavioral disorders, and insomnia
5. What is the worst COVID-19 can do to the brain? According to Dr. Milczarek, it is severe hypoxia and thus a severe stroke, but not only
6. More information can be found on the Onet homepage

Monika Mikołajska / Medonet: There is more and more talk about the long covid, including complications for the nervous system. It is not only about the brain, but also the spinal cord and nerves. Voices that covid changes the mental state appeared in the first months of the pandemic. It sounds very disturbing.

Olga Milczarek, MD, PhD, neurologist: I will start quite unusual, but it will make it easier to understand the effects of the coronavirus on the nervous system. Although we still know very little about SARS-CoV-2 itself, we got to know some of its behavior. It can be said that it works a bit like the HIV virus. That is, it affects the reaction of our immune system and thus regulates the course of the infection itself. Although, of course, SARS-CoV-2 does not integrate permanently into cells, as does the HIV virus.

There are studies that have shown that patients with COVID-19 who were given retroviral drugs (and such are used for HIV) suffered much less severely than those who did not receive such drugs. This indicates that there is some common pathway with these pathogens. That they both act on the same receptors, thus modulating the immune response.

The body reacts to SARS-CoV-2 in two stages. First, it is the process of virus invasion itself, then it comes to the so-called a cytokine storm. Scientists have watched this phenomenon very closely.

What is a cytokine storm?

It is a state of an excessive and uncontrolled defense reaction of the body. It causes a massive release of pro-inflammatory components (triggering the body’s defensive reaction), i.e. cytokines. In the case of SARS-CoV-2, the reaction is much more violent than with all other viruses known to us. This shows how difficult and toxic this pathogen is.

Of course, you could say that such a violent reaction happens every time a new virus emerges. In the case of SARS-CoV-2, however, it turned out that the activation of pro-inflammatory cytokines is stronger.

This is not a good signal.

I will say more, this is very bad. An excessive inflammatory response can result in complications, including damage to your own tissues. Moreover, in most viral diseases, this reaction takes place throughout the body. The virus does not choose one place in the body, one particular organ, as bacteria sometimes do – it attacks many areas at once. And the greater the body’s tendency to cytokine storms (and this is an individual trait), the more organs are involved in the inflammatory disease process and the greater the damage may be.

What’s more, it also turned out that SARS-CoV-2 works similarly to viruses with affinity for the central nervous system (it has a neurotrophic effect). Such pathogens include, among others cytomegalovirus, herpes simplex, pox virus. Whenever they appear in the body, it is an alarm signal for the doctor that they can attack the nervous system, activating the inflammatory process in it. This also applies to our coronavirus.

In the first waves of the epidemic, severe headaches were very often the first symptom of COVID-19. It made you think …

Exactly. Scientists then concluded that SARS-CoV-2 has a tendency to attack the nervous system, so that it must trigger a defensive reaction in it. There was something else for that. Disturbances in smell, taste, and paraesthesia that patients reported during or after the disease, suggested that the coronavirus also caused damage to peripheral nerves.

It even happened that these symptoms were dominant in patients. It’s not that all COVID-19 patients had respiratory failure, some experienced neurological symptoms. I also had such patients. Some people have complained that they cannot sleep because they are tired of Restless Legs Syndrome, which is increased paresthesia of the lower limbs. Subsequent studies have shown that the coronavirus causes the so-called thin fiber neuropathies – as a result of SARS-CoV-2, the thinnest nerve fibers were damaged and, as a consequence, sensory disturbances, including pain sensation.

And what happens in the brain itself when SARS-CoV-2 attacks?

As one professor who taught me about neuroinfection said, there is no encephalitis, no meningitis, or even a viral brain irritation that leaves no neurological trace. In the case of SARS-CoV-2, the process is even more complex.

Olga Milczarek, MD, PhD

The pathogen itself causes an inflammatory response. This is the first cause of the appearance of cerebral pocovid fog. The second thing we know is that SARS-CoV-2 caused excessive coagulation – in the course of infection, patients very often experienced strokes and embolisms. So it happened that small vessels of the brain, already under the inflammatory process, were additionally “clogged”. These two mechanisms have been confirmed in research. Importantly, the damage largely affects not the structures of the brain itself, but the connections between its cells.

Patients with disease may also develop a severe neurological syndrome in COVID-19. Including extensive stroke (if the blood clot was in large vessels) or severe CNS hypoxia. The massive inflammatory response could result in encephalitis and damage.

To investigate exactly how SARS-CoV-2 changes the brain, we would need to take samples from people who died from COVID-19. Perhaps this is a topic for further analysis. Most of the studies to date have been carried out on patients who have survived the coronavirus infection.

There is even talk of the neuroinvasion of the coronavirus. What is the scale of this phenomenon, according to the doctor, how many convalescents have complications from the nervous system?

It is estimated that this postovid invasion of the central nervous system affects 62 to 70 percent of people. patients. That’s a lot.

You have now mentioned postcovid symptoms, and the term long covid is also often used. However, it is not the same.

This so-called long covid is up to 12 weeks after the infection (it is assumed that it should disappear within four weeks). However, if the neurological symptoms, including cognitive disorders (e.g. problems with memory, concentration, perception) persist beyond these three months, we are dealing with the post-covid syndrome. One of the elements of the latter is brain fog.

Brain fog is a colloquial rather than a medical term. What is this brain fog really? How to recognize it?

Patients define it very differently. Some people compare it to the symptoms of jet lag, i.e. distraction, mental disruption, difficulty concentrating thoughts, remembering, counting, reading. Brain fog is also a disorder of the so-called verbal fluency, i.e. fluency and speed of recalling and pronouncing or writing words. A large proportion of the patients said that their brain was like foam, that it did not absorb new information as it did before.

And it is not that patients convince themselves of these problems or make them up. COVID-19 simply results in this type of disorder. People actually experience them, no matter what the circumstances.

Moreover, this so-called neurocovid means not only strictly neurological symptoms. It also has psychological effects, or to be more precise – neuropsychological.

Of course. Depression, anxiety, behavioral disorders, and the aforementioned insomnia may appear. These are also complications that contribute to the clinical picture of postcovid syndrome. They are also caused by damage related to the strong inflammatory reaction and microcoagulation (hypoxia), which we talked about.

Of course, changes in the brain, or rather in brain connections, are most often microdamages, very rarely seen during MRI or CT scans. They could be revealed by neuropsychological examination, i.e. appropriately selected tests.

There is also a puzzling issue in post-COVID-19 neurological disorders. It is known that the changes do not depend on the severity of the disease. Why can light mileage be severe?

There were studies that said that most nervous system attacks are experienced by young people suffering from COVID-19. Indeed, most young patients with the infection lost their sense of smell and struggled with severe headaches. In the elderly, systemic symptoms were the most important.

It may be that when COVID-19 affects the elderly, often afflicted with other ailments, it focuses on the most vulnerable areas already affected by the disease. Of course, there are also exceptions to this rule. Because, as the saying goes, “in medicine and in love there is no certainty”.

You mentioned you had patients with neurovocidosis. Do you have a memory stuck to you that you could share with us?

I went through it myself, very classic indeed. The infection started with very severe pain and dizziness. I have never experienced such a headache as in the course of COVID-19. The symptoms resembled symptoms in an irritation of the meninges. During the infection, I lost both my sense of smell and taste. It is said that these senses should return after 10-12 weeks, for me it took six months. In addition, there were very strong pains in the lower limbs, caused by damage to the small nerve fibers. They were so annoying, I couldn’t sleep. I lasted long-covid for about eight weeks. I felt very tired all this time.

Then postcovid discomfort began, including difficulty remembering. More than once, I had the feeling that I couldn’t find the right words, it was difficult for me to concentrate on my own statements. This lasted for quite a long time, even a year, I think.

Is it known to what extent the changes experienced in neurocovida may be permanent? The brain is a very delicate structure

It is suspected that even 18-20 percent. SARS-CoV-2-induced cognitive deficits in patients may be permanent. In other words, if the course of COVID-19 does indeed develop into CNS microbrombotic changes, they rarely regress completely.

Can your doctor point out what the worst COVID-19 can do to the brain? What is the most serious complication?

It is definitely severe hypoxia and therefore a severe stroke. Another serious neurological complication is encephalopathy, i.e. encephalitis (this is the brain’s response to a virus). Many such cases have been described, incl. in fetuses or children born of pregnancies with COVID-19.

You mentioned that up to 70 percent. patients may experience neurocovid. What could be the consequences of so many people with neurological problems?

We do not know this for sure and we will not know it for a long time. Years of observation are needed. However, we can suspect that SARS-CoV-2 will accelerate the aging of the CNS, which is simply dementia. Whether people who have passed COVID-19 will experience it, or it will shorten their lives secondarily – time will tell.