As COVID-19 increasingly infects us, scientists are closely watching the strange and frightening damage it can cause to our bodies.
We have known since the beginning of the pandemic that this disease wreaks havoc on more than just the respiratory system, also causing gastrointestinal problems, damage to the heart and blood clotting disorders.
Now, a year after the pandemic began, in-depth autopsies of patients with COVID-19 have revealed more details of widespread inflammation and brain tissue damage. This can help explain the deluge of neurological symptoms that have manifested in some patients, from headaches, memory loss, dizziness, weakness and hallucinations to more severe seizures and strokes.
Some estimate that up to 50 percent of people hospitalized with COVID-19 may have neurological symptoms that can leave people struggling to do even ordinary daily tasks, such as preparing a meal.
“We were completely surprised. Originally, we expected to see damage caused by a lack of oxygen,” said Avindra Nath, physician and clinical director of the National Institute of Health (NIH).
“Instead, we saw multifocal areas of damage that are often associated with strokes and neuroinflammatory diseases.”
NIH researchers, including physician Myoung-Hwa Lee and Nath, underwent thorough examinations of the brain tissues of 19 deceased patients. They ranged in age from 5 to 73, and many had risk factors for severe coronavirus, including diabetes and cardiovascular disease.
Using a powerful magnetic resonance microscopy, Lee and his team identified 10 patients with brain abnormalities. Closer examination of the microscope revealed hyperintensities – bright spots in the micrograph image of brain samples – that fluorescent microscopy proved to be fibrinogen (a blood protein) leaking.
T cells and specialized immune cells in the brain, microglia, surrounded these points in several patients; there were also dark areas of clotted bleeding. This led the researchers to conclude that these patients had experienced several small brain bleeds – a type of damage usually associated with inflammation in the brain.
“The very small blood vessels in the brain were leaking,” Nath told NPR. “And it wasn’t uniform – you would find a small blood vessel here and a small blood vessel there.”
It is not just those who are seriously ill enough to need intensive care, or with pre-existing illnesses, who exhibited neurological symptoms of COVID-19.
“We saw this group of younger people without conventional risk factors who are having strokes and patients with acute changes in mental status that are not explained otherwise,” said neurologist Benedict Michael of the University of Liverpool Nature In September.
Patients suffered delusions and developed psychosis. In one case, a 55-year-old woman started seeing lions and monkeys in her home, before believing that a friend or family member had been replaced by an identical impostor (a Capgras delusion).
Despite tests to detect the virus in brain tissues, Lee and the team found no trace of SARS-CoV-2, but caution in their report: “It is possible that the virus was eliminated at the time of death or that the number of viral copies has been below the level of detection by our trials. “
Although other studies have found traces of the virus in the brain, the levels were low and appear to be rare.
“So far, our results suggest that the damage we saw may not have been caused by the SARS-CoV-2 virus directly infecting the brain,” said Nath. Instead, the damage may be due to the body’s inflammatory response to the virus, he explained.
Due to the small sample size and limited clinical information, the team says that it is not yet possible to draw direct conclusions. But his findings are in line with EEG tests that revealed encephalopathy in patients with COVID-19 – disturbances in the brain’s typical electrical activity that can spell swelling and inflammation.
It is also in line with studies showing that the virus can trigger other dangerous immune responses that, in some cases, cause even more damage than the virus itself directly causes.
Researchers are concerned about the long-term health implications of brain inflammation, as it is associated with memory loss and Alzheimer’s disease and some patients are already experiencing persistent neurological consequences, such as chronic fatigue and Guillain syndrome. Barré.
“In the future, we plan to study how COVID-19 damages the blood vessels in the brain and whether it produces some of the short and long-term symptoms that we see in patients,” said Nath.
His report was published in the New England Journal of Medicine.