Why Is COVID-19 Coronavirus Causing Strokes In Young And Middle-Aged People?
We know that COVID-19 coronavirus attacks the lungs resulting in severe inflammation as the lungs fill with fluid, ultimately reducing their ability to fulfill their intended purpose: transferring oxygen from the lungs to the bloodstream via red blood cells.
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We are also learning more and more about the devastating effects of this virus as it attacks other organs including the kidney, heart and the brain. However, the virus’s ultimate target that may inflict the most damage—via either a direct effect of the virus, hypoxia, (low oxygen), secondary inflammation or disseminated intravascular coagulation (DIC)—are blood vessels, leading to formation of blood clots, or excessive bleeding (DIC) in some cases, a consequence of consumption of clotting factors.
But the virus does not seem to be attacking just any size blood vessel in young adults, but larger blood vessels that feed important parts [of] the brain that are critical to movement, thinking, and breathing. (These include large blood vessels such as the middle cerebral artery [MCA] or anterior cerebral artery [ACA] that supply large and critical areas [of] the brain.) When blockages in larger blood vessels known as “large vessel occlusions” or LVOs as they are referred to develop, the effects can be permanent or life-changing, if not immediately diagnosed and treated immediately.
In a letter to be published online April 29 in the New England Journal of Medicine, researchers from Mount Sinai in New York City describe five COVID-19 patients who suffered large vessel strokes over a 2-week period, all under the age of 50, according to reporting by Medscape Medical News. Of the five patients [in] the series, one patient died, one is still hospitalized, one was discharged home, while two are still in rehabilitation. What’s also striking is that the five patients either had mild or no symptoms of COVID-19. The study was led by Dr. Thomas Oxley, from the Department of Neurosurgery at Mount Sinai Health System.
Oxley explained that “we’re learning that this can disproportionately affect large vessels more than small vessels in terms of presentation of stroke.” He also offered that inflammation in the walls of the blood vessels may be triggering the process of thrombosis, or formation of blood clots.
This is not the only report of increased risk of clotting seen in young COVID-19 patients. Other recent research out of the Netherlands also noted an elevated rate of thrombotic complications seen in 184 critically ill COVID-19 patients with pneumonia. The 31% rate of thrombotic complications observed in the study included both venous and arterial clots, arguing for the need for prophylaxis in such high-risk patients. Their series included patients with pulmonary embolism (PE), deep venous thrombosis (DVT), ischemic stroke, heart attack (myocardial infarction), or systemic arterial embolism.
Meanwhile, an international group of researchers led by cardiologists from New York-Presbyterian/Columbia University, and the Center for Outcomes Research and Evaluation, Yale School of Medicine recently published guidelines in the Journal of the American College of Cardiology regarding the diagnosis and management of thrombotic complications seen in patients with COVID-19. These guidelines were also endorsed by the International Society on Thrombosis and Hemostasis.
The pathology underlying the increase in cases of clots [and] strokes, as well as bleeding, requires in-depth study at the molecular level as we learn more about the exact effects of the virus on the cells lining the walls of blood vessels (endothelium) as well as the clotting cascade. That said, the use of prophylactic anticoagulation using low molecular weight heparin (LMWH) over direct oral anticoagulant (DOAC) may be advisable for now, as a result of the much longer half-life (in DOACs) that may increase the risk of bleeding, specifically in cases when interventional procedures may be necessary.
Interestingly, a letter recently published in the New England Journal of Medicine from investigators at Weill Cornell Medicine evaluating the first 393 COVID-19 patients seen at two hospitals noted that clotting complications were only noted in slightly over 7% of patients, a number typical for ICU patients in the pre-COVID-19 era. What’s unclear is whether this low figure is reflective of the remainder of their patient experience related to clotting at their institution as the pandemic continues.
Recently, Broadway star Nick Cordera suffered a thrombotic complication related to COVID-19, requiring the amputation of one of his legs, highlighting the significant clotting risks associated with the virus.
While the risks of clotting related to COVID-19 are now apparent, many patients who experience stroke-like symptoms including weakness, difficulty speaking, dizziness or numbness have been reluctant to seek care in the emergency department—for fear of exposure to the virus itself. Yet this delay to seek care could be disastrous, with life-altering consequences (paralysis, loss [of the] ability to think or speak) including death. In Oxley’s series, two of the five patients delayed calling 911 for assistance.
As a result, the message to everyone, especially young adults, is not to delay care in the setting of stroke-like symptoms during the pandemic. The symptoms could very well signal a stroke—regardless of your age.
A clot-busting drug known as tissue plasminogen activator (TPA,) the first line treatment, as well as endovascular or catheter-based approaches (in delayed presentations) could be lifesaving.
Data indicates that removing the blood clot in the vessel via clot retrieval (using endovascular techniques or catheters) is the most effective approach for large vessel strokes. However, this should ideally be performed within 6 hours of onset of symptoms, but up to 24 hours in other cases based on neurologic exam and degree of symptoms.
As a result, it’s important to call 911 not only for difficulty breathing or chest pain, but also for stroke-like symptoms in the era of COVID-19.
Time is brain is the take-home message.