Are COVID-19 and Strokes Connected? Your Frequent Questions Answered


The connections between COVID-19 and stroke may boil down to a combination of factors, including complications that come with an infection or pre-existing conditions. Here are some things you need to know about COVID-19 and strokes:

  • COVID-19 can increase the risk of stroke.
  • The virus may cause sudden strokes.
  • Strokes have occurred in young adult COVID-19 patients. 
  • COVID-19 is linked to abnormal clotting.
  • It may play a role in brain damage.
  • COVID-19 can cause abnormal blood clotting.
  • Read on to learn more about each finding.

COVID-19 Raises the Risk of Stroke

COVID-19 may increase the risk of stroke. Studies show that up to 4.9% of COVID-19 patients suffer an acute ischemic stroke during their first hospitalization. This increased risk of stroke is due to a number of factors brought about by COVID-19, such as increased blood clotting, as well as diabetes, and high blood pressure.

What is an ischemic stroke? This is a common type of stroke that occurs when a blood clot blocks the blood supply to the brain.

Some lifestyle factors also set the stage for the risk of stroke. These include smoking, poor diet, and high cholesterol levels. These long-term risk factors leave blood vessels vulnerable to a sudden trigger event, like a viral infection.

COVID-19 May Cause Sudden Strokes

Doctors and researchers alike who have been working on COVID-19 patients have noted that severe cases of the disease involve the rapid formation of blood clots. This increases the risk for stroke, as well as heart attacks and heart failure.

In a study conducted at Baylor St. Luke’s Medical Center (a St. Joseph Health sister facility) by Baylor College of Medicine, researchers found that more than half of admitted COVID-19 patients developed significant blood clots. A majority of these cases evaded routine blood clot screenings. 

COVID-19 Can Cause Strokes in Younger Adults

While rare, it is a possibility. In a report published in April 2020, five cases of large-vessel stroke were recorded in COVID-19 patients who were all below the age of 50. All patients were previously healthy, had no pre-existing conditions, but had presented new-onset symptoms of large-vessel ischemic strokes. 

Why Strokes Occur in Younger Adults With COVID-19

The occurrence of strokes in younger adults is one of the more mystifying twists brought about by COVID-19. A common theory is that younger and healthier patients can easily bypass and recover from the respiratory issues brought about by the virus but develop more serious issues later on. Infected patients have been known to experience the deadliest type of stroke, where large clots block blood flow, damaging parts of the brain. These include areas that are responsible for speech, decision-making, and movement.

COVID-19 Can Cause Abnormal Blood Clotting

The occurrence of strokes in COVID-19 patients may be the result of unusual clotting problems indirectly brought about by the virus. A study done in November 2020 found parallels between COVID-19 and antiphospholipid syndrome (APS), an autoimmune condition that causes similar blood-clotting abnormalities. In both cases, a patient’s immune system releases autoantibodies that promote the rapid formation of multiple blood clots in large arteries, veins, and even the most microscopic of capillaries.

COVID-19 May Play a Role in Brain Damage

COVID-19’s most common symptoms are the loss of smell and taste, headaches, fatigue, and brain fog. This has led researchers to believe that the disease may also cause neurological problems. Post-mortem studies on human brain tissue samples reveal that these neurological symptoms are likely caused by the body’s inflammatory response to the SARS-CoV-2 virus.

MRI imaging showed signs of inflammation and bleeding in the olfactory bulb and brain stem. These are areas of the brain that control the ability to smell and regulate heart rate and breathing. Small blood vessels in these areas were shown to be abnormally thin. Many leaked out blood proteins that triggered an aggressive immune reaction.

Genetic material from the virus itself was absent in the brain tissue samples. However, other studies of mouse and human brain tissue have suggested a direct influence of the virus on the central nervous system with signs of viral neurons found in the cerebral cortex.

What To Do in the Event of a Stroke

A stroke can occur to anyone at any age. To recognize a stroke, think F.A.S.T.: 

  • Facial Drooping - Part of the face becomes lopsided or droopy.
  • Arm Weakness - Weakness and numbness in one arm.
  • Speech Difficulty - Slurring speech or inability to speak simple sentences.
  • Time - Time is of the essence, so call 911 and note the time the symptoms appeared.

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