One of the dozens of unusual symptoms that have emerged in COVID-19 patients is a condition that’s informally called “COVID brain” or “brain fog.”
It’s characterized by confusion, headaches, and loss of short-term memory. In severe cases, it can lead to psychosis and even seizures.
It usually emerges weeks after someone first becomes sick with COVID-19.
In a new study, researchers found an underlying cause of COVID brain: the presence of inflammatory molecules in the liquid surrounding the brain and spinal cord (called the cerebrospinal fluid).
The findings suggest that anti-inflammatory drugs, such as steroids, may be useful for treating the condition.
The research was conducted by a team from Memorial Sloan Kettering.
The medical term for COVID brain is encephalopathy. It is a side effect in patients who are receiving a type of immunotherapy called chimeric antibody receptor (CAR) T cell therapy, a treatment for blood cancer.
When CAR T cell therapy is given, it causes immune cells to release molecules called cytokines, which help the body to kill cancer.
But cytokines can seep into the area around the brain and cause inflammation.
When the team first began studying the COVID brain, though, they didn’t know that cytokines were the cause. They first suspected that the virus itself was having an effect on the brain.
The study focused on 18 patients who were hospitalized with COVID-19 and were experiencing severe neurologic problems.
The patients were given a full neurology workup, including brain scans like MRIs and CTs and electroencephalogram (EEG) monitoring, to try to find the cause of their delirium.
When nothing was found in the scans that would explain their condition, the researchers thought the answer might lie in the cerebrospinal fluid.
The team devised a test to detect the COVID-19 virus in the fluid. Thirteen of the 18 patients had spinal taps to look for the virus, but it was not found.
They found that these patients had persistent inflammation and high levels of cytokines in their cerebrospinal fluid, which explained the symptoms they were having.
Some smaller case studies with only a few patients had reported similar findings, but this study is the largest one so far to look at this effect.
The team says the inflammatory markers found in the COVID-19 patients were similar, but not identical, to those seen in people who have received CAR T cell therapy.
And as with CAR T cell therapy, the neurologic effects are sometimes delayed.
The initial inflammatory response with CAR T cell treatment is very similar to the reaction called cytokine storm that’s often reported in people with COVID-19.
With both COVID-19 and CAR T cell therapy, the neurologic effects come days or weeks later.
One author of the study is Jessica Wilcox, the Chief Fellow in neurooncology.
The study is published in the journal Cancer Cell.