Mysterious strokes among young COVID-19 patients may reveal how 'a virus can cause strokes in ways we never knew before,' a doctor says

• New York City doctors have reported a handful of of young patients with mild coronavirus cases who experienced large-vessel strokes. The patients were at low risk for strokes, a new report reveals.
• Such strokes occur when a blood clot travels from the body into an artery in the brain.
• Experts have reported blood clots in patients with severe COVID-19 cases.
• One of the doctors behind the report told Business Insider that stroke-causing clots may be a result of coronavirus-induced swelling in blood vessels.
• Visit Business Insider's homepage for more stories.

Four people in their 30s and 40s were recently admitted to Mount Sinai Hospital in New York City with life-threatening strokes. Their cases were united by a common theme: All of them had COVID-19.

"Large-vessel strokes in young patients are exceedingly rare," Thomas Oxley, a neurosurgeon at Mount Sinai who published a new report about the cases, told Business Insider. "They'd need a past history concerning strokes. But these patients had minimal past medical histories and all came in within two weeks."

The patients, four men and one woman, were hospitalized between March 23 and April 7. In Oxley's paper, published Wednesday in the New England Journal of Medicine, he and his colleagues wrote that "every two weeks over the previous 12 months, our service has treated, on average, 0.73 patients younger than 50 years of age with large-vessel stroke."

So the recent handful of stroke cases stood out.

"What if we're now learning that a virus can cause strokes in ways we never knew before?" Oxley said.

The young stroke patients had mild or no COVID-19 symptoms

Large-vessel strokes are caused by a blood clot that travels from the body into an artery in the brain.

The new report describes how this happened in each of the five recent New York cases. The only woman in the study, a 33-year-old, had no prior medical history, the paper says. She experienced a COVID-19-related cough, headache, and chills in the week prior to her stroke. Then, over a period of 28 hours, her speech became slow and slurred as her jaw muscles shut down. Her left arm and leg became weak and numb.

At Mount Sinai, Oxley and his colleagues found a blood clot in her brain's carotid artery. They used a "clot-busting" drug to break it up over the next 10 days.

The four male patients, meanwhile, had similar stories. All of them experienced numbness, slowed speech, and temporary paralysis before they went to the hospital, where doctors removed the life-threatening clots. The men ranged in age from 37 to 49; two had mild coronavirus symptoms while the other two reported none at all.

Only one had suffered a stroke before.

'Dumbfounded' by the link between COVID-19 and strokes

Oxley said that since first speaking out about these stroke cases, he's been flooded with emails from other coronavirus patients describing minor strokes.

A 31-year-old man messaged him on Sunday, describing a sudden onset of speech disturbance and numbness, Oxley said. The patient went to the hospital, and an MRI revealed he'd had a stroke in his thalamus.

"I was just dumbfounded by this story of a patient who had never had a past history of stroke," Oxley said.

He added that strokes have also been observed in older COVID-19 patients, but the new trend is reason for additional concern because it involves people in their 30s and 40s without severe symptoms. (Overall, nearly three-quarters of all strokes occur in people over the age of 65.)

Oxley and J. Mocco, another Mount Sinai neurosurgeon, think the link between COVID-19 and the increase in strokes they're seeing has to do with blood clots.

Experts have reported blood clots appearing in various parts of coronavirus patients' bodies, including the lungs. Broadway actor Nick Cordero, who was diagnosed with coronavirus, had to have his right leg amputated after clots formed.

"It's very striking how much this disease causes clots to form," Mocco told Reuters.

Coronaviruses in general have also been known to cause neurological issues like strokes, according to a February study. Roughly 2% of patients in Singapore who contracted SARS (also a coronavirus) had strokes.

A study on COVID-19 patients at three hospitals in Wuhan, China — which is not yet peer-reviewed — found that of 214 patients, 36% had neurological symptoms. That included impaired consciousness and acute cerebrovascular diseases like strokes.

The coronavirus might attack both the lungs and the blood

Scientists aren't yet sure why COVID-19 causes clots, but Oxley said they might be the result of blood vessels' reaction to being invaded by the virus.

The new coronavirus attacks via a specific cell receptor called ACE2, which can be found throughout the body, including in our guts, lungs, hearts, and even noses.

According to Oxley, the virus can also bind to ACE2 receptors in the walls of our blood vessels. That leads the vessels to become inflamed, which can cause clotting. Then once a clot has formed, it can travel to the brain and cause a stroke.

Not everyone's blood-vessel walls have the same level of ACE2 receptors, though. That characteristic is linked to a patient's genetics, rather than their age, Oxley said. That might explain why blood clots appear in patients across age brackets.

Oxley said COVID-19 is teaching his colleagues about a previously unexplored link between viruses, inflammation, and strokes.

"There are other viruses we're going to learn about in the future that may be connected to strokes in the same way," he said.

Read the original article on Business Insider