Why do recovered Covid-19 patients report ‘brain fog’? An infectious disease specialist explains

Many patients who have recovered from Covid-19 report continued fatigue and forgetfulness, a condition being described as the Covid-19 brain fog. While some mild complications of Covid-19 after recovery, such as a persistent low-grade fever, could be more perceived than real, the brain fog does affect patients, lasts longer than expected, but is temporary, said Tanu Singhal, consultant, paediatrics and infectious diseases specialist at the Kokilaben Dhirubhai Ambani Hospital.

Post-Covid infections are among the most common complications, and they are being triggered by unnecessary or long-term use of steroids among Covid-19 patients, Singhal said, adding that it is important to not over-medicate.

Some of the more severe complications, such as thrombosis and myocardial infarction, are rarer, Singhal said, adding that it is important to be alert about anything that is amiss for one-two months after recovery from Covid-19.

Excerpts from the interview:

Broadly, there are two kinds of cases: Covid-19 patients who come to hospitals, and others who may not even get tested or are getting treated at home because the symptoms are mild to moderate. And yet, many of these patients are later displaying post-Covid symptoms, including what is being called the Covid-19 brain fog. Are you seeing this? What have you been coming across?
We are seeing both types of patients. We are seeing mild patients as well because some of them are our own healthcare workers. And there are many people who seek online consultations for mild Covid-19, so we have experience with these patients as well.

The most common problem that I come across is fatigue – that even after recovery, they feel so weak and cannot go back to their usual work. We see that with healthcare workers also – they would come and join work, and then they feel tired and want to go back and rest.

Then, we are seeing that the lost sense of taste and smell takes some time to come back and that causes patients distress. We are also seeing this phenomenon of very low-grade fever persisting for a month, and this is because these people have gotten so used to measuring their temperatures that they keep measuring it and in the evenings, even if they get a little over 99 [degrees fahrenheit], they get worried. So, some of the problems may actually be more perceived than real.

We are seeing these cases of brain fog. Recently, we had a person admitted with us, who had mild Covid-19 and did not need any major treatment and then, a month later, started becoming forgetful –so much so that he used to forget everything. He was becoming very drowsy and withdrawn, and he had to be admitted to a hospital for that. This brain fog also has different spectrums.

One thing is very clear: Covid-19 is not behaving like any other pathogen. It is breaking all boundaries and barriers. Name any kind of post-Covid complication, we have seen it. We have seen people coming in with pancreatitis, strokes, myocardial infarctions, thrombosis, and many other complications affecting almost every organ of the body.

Do the mild post-Covid symptoms also relate to mild symptoms at the onset of the disease?
No, they are not related. People who had moderate to severe symptoms have also had these symptoms later on; they may not have serious problems, but they continue to experience fatigue etc. For a person who has been in hospital, in the ICU, if they have fatigue and other problems after recovery, it is understandable. But for patients who have had very mild symptoms in the beginning, it is unexpected.

We are also seeing a lot of mental health problems triggered, even with mild symptoms, because they have had a lot of anxiety about their condition and social isolation.

Is there any insight as to why there is fatigue or forgetfulness? What could be the trigger?
I think it is because this Covid-19 virus enters the body through an ACE-2 receptor. And these receptors are widely distributed all over the body. That is why the virus can gain access to every system.

It is known that it gains access to the nervous system also, and that is the reason for the loss of sense of taste and smell. Probably that is the reason [for the brain fog]. One [reason] could be actual damage by the virus to these organ systems, and the second could be also a byproduct of the stress a person undergoes during the whole Covid-19 episode.

Is there recovery after that? Or is this a longer-term state?
No, they recover. None of the people, who were complaining of fatigue about a month or two ago, have it now. I have not seen any patient who has had it permanently. It is just that it does not go away as soon as people expect it to go away. But eventually, they recover. So the long-term outcomes, in terms of all these minor symptoms, is quite good.

When you speak of thrombosis or cardiac issues in the post-Covid phase, are these related to prior conditions? Or are these something that people developed completely afresh?
Most times, they develop [it] completely afresh. We have a cohort of about 600 or 700 patients who were treated in our hospital for severe Covid. They are the ones who do not come back with these thrombotic problems because we are not even giving them anticoagulation at the time of discharge.

The people who come back with these problems are generally those who never anticipated it. They come with a stroke, and they have no risk factors. When you evaluate them, you find they had Covid-19 three-four weeks ago. Most patients who come to us with these kinds of Covid-related thrombosis had mild illness earlier.

But the number is very small, [and] that is why people should not panic. That is a common problem: everybody reads about thrombosis in Covid-19, and when they are at home, they do their D-dimer tests [to check for clotting factors that could lead to thrombosis] and if the D-dimer level is high, they ask if they can take anticoagulation. That is not recommended, because if 1,000 people have mild Covid, maybe there will be one who will have a thrombotic complication.

Serious complications are rare. There is nothing much one can do to prevent these from happening – at least the serious complications like thrombosis because anybody who has had mild Covid-19 would not be on anticoagulation etc. to prevent this from happening. I think it is just bad luck. It is only very few people who qualify for anticoagulation after they are discharged from the hospital.

Many more would have fatigue and forgetfulness, but they will recover. Is that your experience?
Yes, they will all recover completely.

When someone is diagnosed with Covid-19, maybe you have caught it early, and it looks like it is mild. Is there anything you can do to prevent a more serious onset once you have recovered?
One of the very important things people should do is to not take steroids if they have mild Covid-19, and do not take too many medications.

Patients who have mild Covid-19 are [being] given azithromycin, hydroxychloroquine, ivermectin, doxycycline etc, for which there is no real scientific basis. They should avoid that. Steroids should definitely be avoided because the most horrible complications that we are seeing post-Covid are actually infections. Covid-19 itself lowers your immunity and on top of that, if you take steroids, your immunity goes down further. So we are seeing people coming with bad fungal or bacterial infections. That is the most common complication we are seeing after Covid-19. And that is avoidable to a certain extent, by not taking medications that are not indicated.

Another thing is, some patients with severe Covid-19 are being treated with steroids for a very long time, which is not recommended. It is recommended for seven to 10 days. But if they go on for long, then they come back with bad infections.

Also, be careful for one month after recovery. If you have anything that is amiss, do not ignore it. Suppose you have recovered from Covid-19 and then suddenly, you start having some symptoms like chest pain or weakness of a limb or you get a fever again, do not ignore it. Once people have recovered from Covid-19, they think that all is well. But you still have to be careful for the next month or two. And in case you have any of these problems, you should immediately consult a doctor.

Overall, where do you think we stand today in terms of our success in combating Covid-19?
At a population level, we do see a decline in the number of cases in the country, which is a good thing. At one point, we had 100,000 cases per day and now we are at about 30,000 to 40,000 cases per day. So there has been a decline. And it seems to be a true decline because testing has not gone down.

In fact, it has gone up. In Mumbai, we actually saw a major decline. The cases have gone up again a bit, but they haven’t reached the peak levels yet.

We are also seeing better outcomes in patients with Covid-19 than four or five months ago. This is [based on] experience from my own hospital where the first three or four months – April, May, June – were quite bad and we were seeing mortality rates of 40%-50% in our patients with severe disease. But after that, the mortality has come down.

There are many factors [for better outcomes]: Patients are now coming in early. There is more awareness. We are using remdesivir, which as per us has made a difference in the outcome of patients. Doctors know how to treat it better. The use of tocilizumab, which was actually causing problems, has come down.

The city of Mumbai, for instance, has seen a fairly sharp reduction in cases compared to the peak. Do you feel that there is much greater herd immunity now and seroprevalence?
Yes, it is, because studies also show that. For example, in the slums, it [the seroprevalence] may be around 50%. In housing societies, there was a study done some time ago, which showed about 15%-20% [prevalence]. Even in healthcare workers, the antibody tests have shown prevalence. So, I think the decline in cases is possibly because of herd immunity because the city has opened up much more than before. And in fact, the compliance to prevention has actually gone down – mass fatigue has set in, people no longer want to stay in their houses, they want to go [out].

It is not over yet. This virus is very unpredictable. So, we should continue to follow social distancing, hand hygiene, and wear masks. Otherwise, we do not know whether we will also face the same situation that Europe is undergoing right now.

You said that remdesivir is working and itolizumab is not. How has the treatment protocol evolved over time?
Our protocol for the past four months has become fairly standard, which includes remdesivir, steroids, low molecular weight heparin to prevent thrombosis and oxygen – these are the four cardinal things. And this [should] remain more or less the same for the next two-three months. There is nothing else in the offing: Convalescent plasma has gone off [the protocol], and similarly, tocilizumab has gone off it. One of the reasons why tocilizumab has gone off is because of the serious infections we started seeing when we were using tocilizumab. So, after the trial said that tocilizumab does not help, we stopped using it.

Now, you might ask why we continue to use remdesivir when the trials showed it does not work. There are two reasons: One is, on personal experience, we felt that it works and our outcomes have become better. Secondly, there is no downside to using the drug except for the cost, because we have used it in many patients and there are no side effects whatsoever. It is a completely safe drug. That also makes doctors offer the drug to their patients because they feel that when there is nothing else, let us at least offer something that is known to work. That is the reason why remdesivir has still stayed in the protocols.

This article first appeared on IndiaSpend, a data-driven and public-interest journalism non-profit.