Hospitals around the US have reported that people aged between 20 and 50 with no risk factors are dying from strokes after being diagnosed with COVID-19. Although the virus was thought to only affect the respiratory tract early on, this finding comes after other evidence showing that the virus impacts almost every major organ system in the body.
Strokes are characterized by a sudden interruption to blood supply. They can be brought on by heart problems, clogged arteries from high cholesterol, and substance abuse. While small strokes often resolve on their own within 24 hours, larger ones can leave permanent damage and are in some cases fatal.
Analyses by doctors so far reveal that those with COVID-19 tend to experience the most deadly kind of stroke. Known as large vessel occlusions, they appear as large blood clots in the brain that destroy key areas responsible for movement, speech and decision-making.
So far, doctors suspect that these strokes are the result of blood problems that produce blood clots in other places in the body too. This comes as clots that form in blood vessels have a habit of moving upwards. For example, a clot that starts in the leg may move into the lungs. There it can cause a blockage known as a pulmonary embolism that stops a person from being able to breathe, a known cause of death among those with COVID-19. Should these clots move further upwards, they may be able to reach the brain where they can cause a stroke.
Whether the clots are due to a direct attack on blood vessels or an autoimmune problem is currently unknown. Also currently unknown is why so many younger patients experience the deadly stroke alongside the virus, especially given that the median age for the deadly stroke is otherwise 74.
One theory suggests that as older patients tend to die from lung damage early on in the infection while younger patients survive, younger patients may then be more susceptible to succumbing to clotting factors than their seniors.
To understand exactly how the virus may cause strokes and other neurological issues, Sherry H-Y Chou, a neurologist and critical care doctor at the University of Pittsburgh Medical Center, and colleagues are currently researching the phenomenon. Together, they will examine health records from thousands of COVID-19 patients treated at 68 medical centers across 17 countries.