COVID-19 Study Finds High Rates of Unexplained Strokes and Delayed Recognition of Symptoms

In a case series study that explored the association of COVID-19 and acute ischemic stroke, researchers have observed higher than expected rates of unexplained or “cryptogenic” strokes, as well as delays in stroke presentations or symptom recognition.

Ischemic stroke, caused by a clot that blocks blood flow to the brain, is the most common form of acute stroke. But in some instances, despite looking for causes of these strokes - by a thorough cardiac evaluation (heart conditions are one of the most common causes); by looking at blood vessels supplying the brain or by testing for increased blood clotting conditions - the cause cannot be determined.


In the study, researchers from the Emory University Hospital (Atlanta, GA, USA) looked at COVID-19 patients with ischemic stroke. Out of 396 ischemic stroke patients admitted during the study period from March to July 2020, 13 were diagnosed with COVID-19. Researchers found the occurrence of stroke greater in COVID-19 patients who had risk factors like diabetes, hypertension, hyperlipidemia or atrial fibrillation/flutter. Males and African Americans were predominantly affected by strokes in the study.

“Interestingly, while cryptogenic strokes account for only 10-30% of all strokes, in our study we found it in 69% of the patient population which is extremely high and suggests the possibility of COVID-19 as a likely contributory factor in this presentation,” said Dinesh V. Jillella, assistant professor of neurology, Emory University School of Medicine. According to Jillella, as compared with the patients who did not have COVID-19, this was a statistically significant difference of 69% of strokes of cryptogenic etiology in the COVID-19 ischemic stroke group as compared to only 17% in the non-COVID ischemic stroke group.

Additionally, the study observed a prolonged average amount of time to presentation and symptom recognition averaging up to five days, a potential impact of the COVID crisis. These delays limited the use of acute reperfusion treatments, including drugs and surgery, to restore blood flow in or around the blocked vessels which can only be used when patients present within a 24-hour period. According to the researchers, the delayed presentations could be a result of patients waiting longer before coming to the hospital due to self-isolation or quarantine precautions or the fear of contracting COVID that have led to a general decline in acute stroke evaluations.

The study findings highlight the need for increased community awareness/education regarding the urgency of stroke symptoms and the need to ensure rapid evaluation to facilitate early stroke treatments. These findings support the idea that the hypercoagulable (increased clotting) state from COVID could contribute to stroke presentations and also show the issues with regards to delayed presentations and symptom identification in the setting of COVID.

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Emory University Hospital