The Scientist: COVID-19’s Effects on the Brain

The image above shows a slice of a deceased COVID-19 patient’s olfactory bulb, illustrating an area (the blotch on the left) with significant leakage of the protein fibrinogen (fluorescent green) into the tissue, which researchers think is likely the result of damage to small blood vessels. Courtesy of Dragan Meric

Neurological symptoms are not unheard of during pandemics. A British throat specialist observed in the late 1800s that influenza seemed to “run up and down the nervous keyboard stirring up disorder and pain in different parts of the body with what almost seems malicious caprice.” In fact, many patients during the 1889–92 pandemic at the time became afflicted with psychoses, paranoia, stabbing pains, and nerve damage. Scholars have also linked the 1918 flu pandemic to parkinsonism, neuropsychiatric disorders, and other symptoms, although there is some debate around whether some of them were actually caused by the pandemic.

The fact that SARS-CoV-2 is also associated with neurological symptoms isn’t entirely surprising, although the sheer numbers of patients developing such symptoms has alarmed some scientists. The list now includes a range of symptoms, from delirium, strokes, peripheral nerve damage, inflammation of the brain, as well as long-term symptoms like headaches, fatigue, and cognitive difficulties.

Researchers are hard at work trying to figure out how SARS-CoV-2 causes such symptoms. The results so far are a bit puzzling. Though a handful of autopsy studies have found signs of damage in the brains of some COVID-19 patients, it’s still not clear if the virus directly infects the brain. This has pushed researchers to come up with other explanations via which it could affect the human brain.

“I think all of us probably . . . would agree that there is no overwhelming infection of the brain,” Avindra Nath, a neurovirologist at the National Institute of Neurological Disorders and Stroke, told me. “If there is, it’s a very, very miniscule amount. That cannot explain the pathology that we see. It has to be something more than that.”

Read the whole story at The Scientist!