“Coagulation cascade”. A neurologist explains why people with COVID-19 often have strokes and strokes

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Scientists working on the SARS-CoV-2 virus from the beginning of the pandemic noticed that it had a particularly dangerous property. Namely, after entering the body, it triggers the coagulation cascade – a series of mechanisms the effects of which may even affect the lives of patients. One of the effects of COVID-19 infection is strokes, recently diagnosed even in children. How do they occur and whether we can protect ourselves against them, explains the neurologist Dr. Łukasz Jasek.

1. Since the start of the pandemic, doctors have observed that patients who contract coronavirus are more likely to experience strokes
2. – U 2 to 6 percent patients who have a severe course of infection, have been diagnosed with ischemic strokes – explains the neurologist Dr. Łukasz Jasek
3. Strokes affect not only elderly and sick people, but also younger people without comorbidities, and even children
4. The doctor urges not to ignore any alarming symptoms. Doctors have only 4,5 hours from the onset of stroke symptoms to initiate effective treatment
5. More information about COVID-19 can be found on the TvoiLokony home page

Monika Zieleniewska, MedTvoiLokony: Recently, a lot has been written and said about strokes caused by coronavirus infection. What kind of stroke is at risk for people with COVID-19?

Dr. Łukasz Jasek: These are all three types of stroke. First, ischemic stroke, which occurs as a result of a sudden closure of an artery by an embolus or a growing thrombus. This stops blood flow, so a specific region of the brain is no longer supplied with it. Ischemia, secondary necrosis and necrosis of the nervous tissue are present, and the patient presents neurological symptoms.

And another one?

This is a hemorrhagic stroke, colloquially called by patients a stroke. We talk about it when there is a rupture of a vessel and a hemorrhage. The clinical effect is very similar to an ischemic stroke – damage to the nervous system. In contrast, the third type of stroke is the rarest, although its incidence has increased during the pandemic. It is about the so-called a venous stroke, resulting from a thrombosis of the veins in the central nervous system, which leads to blockage of the outflow of blood from some region of the brain. The difference is that it is not the blood that gets blocked, but the drain. Of course, neuroscientists have known about all these strokes for a long time, but we have seen their severity since the start of the pandemic.

The rest of the conversation under the video.

How does medicine explain the link between coronavirus infection and strokes?

It has been scientifically confirmed that the SARS-CoV-2 virus triggers the coagulation cascade. The infection causes an increase in the level of procoagulant factors – enhancing coagulation, such as: fibrinogen, D-dimers (proteins that appear in the blood serum during the dissolution of a clot – fibrin), and in many patients the number of platelets also increases. This is just one of the mechanisms it triggers.

The second mechanism, also causing strokes, is the inflammation in the body itself. We are then dealing with an increase in the level of C-reactive protein, the so-called CRP, which is one of the primary markers of inflammation. The level of interleukins 6 and 7 also increases.

So, is inflammation fundamentally responsible for a stroke?

All inflammatory markers, or inflammatory proteins, that are formed in the body during an infection make the plaque less stable and then rupture. It breaks open, and this causes strokes. But that’s not all. Both the inflammatory process and the activation of the coagulation cascade during COVID-19 infection make this plaque grow faster.

I understand that all these mechanisms overlap?

There is also a third cause, I mean cardiac disorders. Both cardiac arrhythmias, which are quite common in COVID-19, and myocardial infarctions. They may secondary to ischemic stroke.

Finally, I will add something that must not be forgotten, I mean the way the virus enters the body. It attaches to the receptors of the angiotensin-converting enzyme. The enzyme responsible, inter alia, for blood pressure control. When SARS-CoV-2 enters the bloodstream, it causes the endothelium of the vessels, the inner part of it, to malfunction. The clotting sets in, which causes the blood vessels to close. Of course, a stroke can happen to anyone and in different situations, but during a coronavirus infection, the processes that favor it are much more intense.

What do the statistics say about COVID-19 strokes?

Depending on the research, approximately 2 to 6 percent. patients who have a severe course of infection have been diagnosed with ischemic strokes. This is quite a high percentage, and there are not many diseases that can be compared to COVID-19 in this respect. And even if they are, they are not so frequent and not available on such a scale. I would like to point out how incredibly common the coronavirus infection is nowadays, so when we convert this 6 percent for the number of patients, this is a really large number.

Does the gender or age of patients play a role in covid strokes?

At the same level as in general for strokes. Risk factors play a similar role here. The problem is something else.

What?

The fact that we see a lot of patients who have not developed diseases that are identifiable as risk factors or have diseases that are subclinical without symptoms. I am thinking, for example, about some minor bleeding disorders. And now, after being infected with the coronavirus, people who are theoretically healthy, because they have not had any symptoms and have not complained about anything, suddenly start the aforementioned clotting cascades, causing a stroke.

We are still unable to identify patients who will experience mild and severe COVID-19. Sometimes we ourselves are surprised when we compare two people of similar age, functionally similar, biologically similar and in one the disease is quite mild and in the other quite the opposite. We do not know the factor responsible for this.

It is probably not a single factor, but if we can find it, it will be easier for us to choose from the pool of sick patients at risk. We will know who to protect first, and whom to approach more calmly, treating only conservatively.

Is a stroke always associated with a severe COVID-19 course?

Most often this is the case, but we do not have statistics on mildly ill patients. Besides, such statistics could be distorted.

Dlaczego?

We have studies that say that patients with the so-called transient ischemic attack, or transient disturbance of blood flow in the brain, with transient symptoms, i.e. mild strokes, they report to a doctor less frequently than before the outbreak of the pandemic. Probably for fear of infection … Perhaps in the future we will be able to check if something has also happened in people with mild COVID-19. Meanwhile, we observe patients who underwent it quite mildly, did not have any special risk factors, and yet report some complaints. When we do the examination, it turns out that they have had an ischemic episode of the brain, we find changes or some very discreet neurological symptoms. It does happen.

How long after the onset of an infection can a stroke occur?

There is no specific time. The very fact of the severe course of COVID-19 is already dangerous. Such patients should absolutely be hospitalized. This gives us the necessary room for maneuver, because time is the most important thing in a stroke. This is a key issue. To carry out thrombolytic treatment, i.e. dissolving what has blocked the vessel – a thrombus or embolism – we have 4,5 hours. from the onset of symptoms. We have 6 hours to perform a super-effective, modern mechanical thromboctomy therapy.

When a patient is hospitalized, we observe him and are able to catch a stroke quickly. At home, however, it can be different, so we appeal: if any disturbing symptoms appear, you need to call a card. On the occasion of this interview, I also urge patients not to be afraid. We have adequate safeguards in hospitals, and even if they become infected with the coronavirus, we are able to treat them while treating a stroke. If the patient does not report to the hospital, our hands are tied, because after 6 hours we cannot offer any effective therapy.

Publications on strokes in children with COVID-19 are emerging increasingly. Do you think the problem may be growing?

In fact, strokes do happen in children, and much more often in children with covid. Paradoxically, it also depends a bit on the literature. Please remember that this is a relatively fresh topic. The children did not get sick during the first and second waves. In 2020, we hardly admitted them to hospitals. Now we see a lot of infections, but we are just starting to collect data. In addition, they are quite strongly shot – from a few cases per 100. up to 4 – 6 percent, which would be the same percentage as in adults.

While in adults we most often know about specific risk factors, such as: hypertension, diabetes, heart disease, in the case of 10- or 12-year-olds, we do not even have any medical history.

I am not saying that we should be afraid in advance, but if the child is sick, we must see a doctor as soon as possible. Let us not charm reality, do not be afraid of the test result, because it determines our behavior. It is a pity to risk a child’s life. The most important thing in medicine, whether it is neurology, orthopedics or surgery, is prophylaxis. In the case of COVID-19, vaccination is a preventive tool to prevent serious diseases of children.

What are the consequences of strokes in children?

Exactly the same as in adults. If luck is favorable, the stroke is minor, and intervention occurs quickly, the level of disability will be low. On the other hand, if the stroke is extensive, because, for example, a child arrives at the hospital too late, it may result in disability. According to reports at our disposal, the course of COVID-19 in children is more severe than in the first and second waves. The virus has clearly mutated and the Delta variant is more virulent.

And do we know anything about the Omicron?

It is too early, only three weeks have passed since full identification. We do not have direct evidence that children are infected only by Delta, but the only thing that changed significantly between 2020 and 2021 was a new mutation. Our genetics have not changed, so the factor has to be on the viral side.

I would also like to add that vaccination not only protects the vaccinated person, but the fact that I am vaccinated prevents the virus from multiplying intensively in me, making me less infectious to everyone around me. In addition, the virus multiplies less frequently and will mutate less frequently. If it makes 20 billion copies, the risk of mutation is high, and when it makes a million copies, it will be incomparably lower. This is crucial why we want so much vaccination to be as common as possible. The point is that the virus should be as least virulent as possible, that it mutates as little as possible and that we have time to learn to fight it, because we are still at the stage of looking for the best weapons.

Have you personally experienced a COVID-19 stroke case?

I was treating a patient, a 60-year-old man, who was completely healthy prior to the coronavirus infection, with no comorbidities. He became infected and suffered an ischemic stroke during antiviral therapy in the infectious diseases ward. It caused some deficits, thankfully small. Now the patient is functioning fairly well, but it turned out that a few weeks after discharge from the hospital, he developed a pulmonary embolism in good condition. The man was cured, he did not have another infection, he was protected in the prevention of stroke, so the risk of further cardiovascular or thrombotic events was minimized, but a pulmonary embolism appeared. This is evidence of how strongly the coronavirus affects clotting. The fact of getting COVID-19, having had an ischemic stroke and starting prophylaxis does not constitute 100% protection. That’s why it’s best not to get sick …

… And we’re back to vaccinations again.

I looked at the statistics, Germany is twice as high as us, and the death rate due to COVID-19 is only 1,3 times higher. But the vaccination rate is much higher there. As the fifth largest country in the European Union, we are in the lead in terms of the number of deaths, and this is due to two things – firstly, the lack of vaccinations and, second, the failure to apply the DDM rules.

In conclusion, if we confirm the infection with the coronavirus, we must not underestimate any symptoms.

Yes, most patients have very good treatment effects and, most importantly, they remain fully functional. Fortunately, most strokes survive, although medicine is not mathematics, we are not able to predict everything from start to finish, although we are able to help and, above all, prevent long-term complications.

Remember that a stroke is not a disease of one person in the family. If a patient has a high level of paresis, the whole family “gets sick”. Relatives have to look after a disabled person, they have to reformat their whole life. While post-hospital rehabilitation works relatively well for us, the later stages, i.e. professional activation, social activation, do not come out as well. So if we can avoid such a serious complication, disability, then it should be done. Time matters! There is a popular saying in neuroscience: the brain is time, time is the brain, and in fact it is true.