Not long after the first wave of COVID-19 infections, doctors around the world began to notice something strange – a series of persistent effects that persist in patients, long after they seem to have recovered otherwise from the virus.
These unusual neurological symptoms – including fatigue, memory loss, confusion and other abnormalities – are sometimes known as “brain fog” or “COVID brain”, and new research could have identified a root cause of the condition.
“We were initially approached by our critical care colleagues who had observed severe delirium in many patients who were hospitalized with COVID-19,” says neuro-oncologist Jessica Wilcox of the Memorial Sloan Kettering Cancer Center (MSK) in New York.
That meeting turned into an extraordinary collaboration between neurology, critical care, microbiology and neuroradiology to find out what’s going on and to see how we can better help our patients.
As part of the new study, Wilcox and other researchers examined the cerebrospinal fluid of 18 cancer patients who were experiencing neurological dysfunction (aka encephalopathy) after being infected with the SARS-CoV-2 virus.
Initially, it was suspected that a continuing viral infection could be the cause of their cerebral fog symptoms, but microbiological analysis of fluid taken from the spinal taps revealed no signs of the virus, suggesting that patients recovered from COVID-19.
However, the search provided an important clue as to what was happening.
“We found that these patients had persistent inflammation and high levels of cytokines in the cerebrospinal fluid, which explained the symptoms they had,” explains MSK researcher and co-lead author of the study, Jan Remsik.
Cytokines are a broad category of proteins that are involved in signaling the immune system.
In some cases of coronavirus, an overproduction of these molecules leads to what is known as a cytokine storm, which can cause excessive inflammation and is potentially fatal.
A similar phenomenon with elevated levels of inflammatory cytokines is sometimes seen as a side effect of chimeric antibody receptor (CAR) T cell therapy, a treatment with immunotherapy that can also cause confusion, delirium, and other neurological effects. which have a resemblance to the COVID brain. the fog.
The thought is that the flood of these inflammatory chemicals from the immune system leaks into the brain, producing symptoms of encephalopathy as seen in patients.
Although this is the largest study to date to demonstrate this potential link between COVID-19 and post-infection neurological effects, we will need more data to address this association.
That being said, the findings here suggest that anti-inflammatory drugs may be helpful in alleviating cerebral fog in patients and may highlight new directions in diagnosing this persistent malaise.
“We used to think that the nervous system is a privileged immune organ, which means that it has nothing to do with the immune system,” explains MSK neuro-oncologist Adrienne Boire.
“But the more we look, the more connections we find between the two.”
The findings are reported in Cancer cell.