“What is unusual is those patients were young — relatively young — with no risk factors for stroke. So patients in their 30s, 40s and 50s,” he said.
Jabbour, a professor of neurosurgery and chief of the Neurovascular Surgery and Endovascular Neurosurgery at Thomas Jefferson University Hospital, said the number of COVID-19 patients in his department was much higher than anticipated.
“And it turned out when we looked back, we looked at patients from March 20 to April 10,” he said. “Around 30% to 40% of the stroke patients were COVID-positive.”
Jabbour was shocked.
He and his colleagues have been studying correlations between the brain and COVID-19 since the coronavirus pandemic started, and he said strokes are not the only way that the brain can be involved with COVID-19.
“We've seen also what we call encephalitis — it means inflammation of the brain,” Jabbour said. “We have seen a case of encephalitis, where the brain developed encephalitis, but it was also due to COVID. So we think that here, it's not a vessel that's being blocked, like in stroke. But in this case, somehow the virus made it to the brain itself — not the vessels of the brain.”
But how does the virus travel to the brain? Jabbour said there are a few theories.
“One theory is the blood is going through the blood flow and then crossing to the brain,” he said. “There's the barrier called the blood-brain barrier. And because of the inflammation, this barrier becomes incompetent and the virus would cross to the brain.”
Another conjecture has also been observed in animal models: “The virus would go in the nose and follow the nerve — it's called the olfactory nerve. It would follow it all the way up to the brain.”
Jabbour and his colleagues in Philadelphia and in other cities are in the process of publishing a paper about their findings on COVID-19, blood clots, strokes and the brain.
“People think that the virus can affect the lungs only. This is not true,” he said. “This virus can affect the brain. It's affecting the brain in a lot of patients that are young with no risk factors. It's causing strokes, brain hemorrhages. And it's very important for the patients to consult right away and go to an emergency room or call 911 whenever they have stroke symptoms.”
The fight against COVID-19 is still in the very early stages, but Jabbour said there is a lot of room to start new trials, like testing if blood thinners can be an effective prevention method for strokes in COVID-19 patients.