Can the flu cause a stroke
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In April 2018, beloved Night Court actor Harry Anderson died at 65 from a cardioembolic stroke, which involves blockage of a brain blood vessel and is among the most common types of stroke. However, one contributing factor that led to his stroke was unusual: a case of influenza.

Viral infections, as simple as those that can cause the flu, or bacterial infections can cause inflammation and dilation of the heart. In Anderson’s case, he developed a cardiomyopathy, or a weakness of the heart muscle, that either caused an abnormal heart rhythm or low output from his heart, leading to development of a clot that traveled to his brain. The bloodstream can carry these clots throughout the body. When a clot reaches a large blood vessel in the head or neck, it can block the flow of blood to the brain, resulting in a cardioembolic stroke.

Anderson’s situation is somewhat rare, but it can happen to people of any age, particularly those with certain risk factors that predispose them to clot-related (ischemic) strokes.

Who is most at risk?

Cardioembolic strokes are known to account for approximately 20 percent of ischemic strokes, though that number likely could be as high as 30 percent if a clot develops because of another heart problem. Patients who have certain cardiac abnormalities or significant vascular risk factors are at increased risk for clot-related strokes. Therefore, these patients also are at greater risk for strokes with virus-related complications as a contributing factor.

Some of these cardiac abnormalities include:

  • Atrial fibrillation (AFib), a type of abnormal heart rhythm
  • Heart failure, or low ejection fraction
  • Patent foramen ovale (PFO), which is a hole in the heart that should have closed after birth but didn’t
  • Hypercoagulable state, or excessive clotting

Additional vascular risk factors include:

  • Diabetes
  • Hypertension, or high blood pressure
  • Hyperlipidemia, or high cholesterol
  • Obesity
  • Smoking
  • Decreased physical activity
  • Heavy alcohol consumption

The risk for stroke increases as we age. However, patients of any age can experience this type of stroke. I remember the case of a young dad, younger than 50, who had some cardiovascular risk factors. He caught the flu from his child and developed a cardiomyopathy. Consequently, he ended up having a stroke on the left side of his brain—the side that controls language in all right-handed people and half of left-handed people. He survived the stroke, though he had to undergo rehabilitation for aphasia, or loss of the ability to speak.

Patients with #heartfailure or #AFib are at greater risk for #stroke caused by a blood clot if they get the #flu and it affects their heart muscle. via @MedStarWHC
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How can someone reduce their risk?

Unfortunately, cardioembolic stroke is less preventable than other types of stroke that are very closely associated to lifestyle choices, such as smoking and high cholesterol. That said, patients can reduce their risk by following some common-sense healthy lifestyle recommendations:

  • Control your cardiac risk factors, which includes identification and management of heart conditions
  • Eat a Mediterranean diet, which emphasizes fruit, vegetables, and healthy fats, such as avocado and fish
  • Get plenty of exercise, which for most people means 30 minutes a day, four to five times a week at a minimum
  • Reduce the risk of viral infections by washing your hands frequently, limiting public outings during flu outbreaks, and getting your flu shot

Just as patients should work to reduce their risk of cardioembolic stroke, they also should be mindful of traditional stroke warning signs, which affect as many as 70 percent of stroke patients. Remember the FAST acronym to identify stroke symptoms and get help quickly:

  • Face: Look for facial drooping or inability to smile
  • Arms: Check if the arms can be raised to assess muscle weakness or paralysis
  • Speech: Check the ability to repeat a sentence or speak without slurring
  • Time: Call 9-1-1 right away if any of these symptoms arise, because time lost is brain lost

Related reading: The need for fast stroke care–and why some patients don’t get it

How is cardioembolic stroke treated?

Cardioembolic stroke tends to block the larger vessels of the brain, a situation called large-vessel occlusion or LVO. These strokes typically are more severe than when smaller blood vessels are blocked.

In January 2018, a new standard of care was implemented in which mechanical thrombectomy, a clot-removal procedure, can extend the treatment window for patients who suffer strokes caused by LVO. This change has the potential to save thousands of lives in the U.S. each year.

In our Comprehensive Stroke Center, we follow these guidelines based on the time a patient arrives after the stroke occurred:

  • 5 hours or less: The patient receives tissue plasminogen activator (tPA), the gold-standard treatment to break up stroke-related blood clots
  • 6 hours or less: If an LVO is to blame for the stroke, the patient can undergo mechanical thrombectomy
  • 6 to 24 hours: The patient will require an MRI or CT angiography scan to determine the magnitude of the stroke and how much tissue is at risk, but since January 2018, it’s still possible to save the patient’s life with mechanical thrombectomy in this timeframe

Cardioembolic stroke risk can be somewhat unpredictable. However, if patients and doctors work together to manage controllable risk factors, and if we’re all aware of the signs of stroke, we can potentially save more patients’ lives—and save more mental and physical function with fast, advanced treatment.

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