Search IconSearch

Why Doesn’t the Mysterious Cryptogenic Stroke Have an Apparent Cause?

What you should know about cryptogenic stroke

Imaging of a person's brain

When you have a stroke, treatment usually depends on what caused the problem with blood flow to your brain. In some cases, despite an extensive workup, the cause of the stroke may not be evident, or “cryptogenic” (of unknown origin).


Cleveland Clinic is a non-profit academic medical center. Advertising on our site helps support our mission. We do not endorse non-Cleveland Clinic products or services. Policy

While this can be frustrating, ongoing research is helping us understand this medical mystery, offering new methods of detection and treatment.

Neurologist Irene Katzan, MD, explains what you need to know about cryptogenic stroke, and how you can prevent strokes in general.

How often do cryptogenic strokes occur?

Ischemic strokes account for 85% of all strokes. These strokes happen when an artery to your brain becomes blocked, usually by a blood clot. About 25% of ischemic strokes are cryptogenic, meaning that tests do not show a definitive cause.

The other 15% of strokes are considered hemorrhagic strokes, which happen when a weakened blood vessel ruptures in your brain.

What are the remedies for cryptogenic stroke?

While there’s research to help uncover the most effective treatments, doctors treat most people who have cryptogenic strokes with aspirin — the kind you find in an average person’s medicine cabinet.

It’s still important to know the signs of stroke so you can get medical attention immediately. “You won’t know if you’re having a stroke while you’re having it. And seconds matter for the initial treatment of all types of stroke, even if the cause is, ultimately, unknown,” says Dr. Katzan.

If you think you or someone you know is having a stroke, call 911 right away. Then a doctor can decide what kind of stroke it is and how best to treat it.

Can the cause of cryptogenic stroke be found?

“One way doctors reduce the number cryptogenic strokes is to perform a thorough evaluation,” Dr. Katzan says.

“The level of medical evaluation after a stroke is critical and the diagnosis of cryptogenic stroke may depend on how intense the effort is to get the reason for the stroke,” she adds.

Doctors typically do the following to find the cause of stroke:

  1. Evaluate your heart.
  2. Monitor your heart rhythm.
  3. Check your blood vessels in your head and neck.
  4. Look at your brain tissue through brain imaging.


Dr. Katzan suggests making sure your doctor takes these four steps. Seek a second opinion if you’re not confident doctors have done everything they can to find out what caused your stroke.

What’s the role of atrial fibrillation in causing strokes?

“Atrial fibrillation (AF), a common type of irregular heartbeat, could cause some cryptogenic strokes,” Dr. Katzan says. However, a stroke diagnosis is difficult if the AF happens intermittently instead of all the time. In other words, it may not occur while doctors are evaluating you.

For Dr. Katzan, the key to classifying fewer strokes as cryptogenic may lie with better, or more continuous monitoring (14 days or more) for AF after a stroke. It’s not always possible to monitor someone full-time in a hospital until their heartbeat is irregular. However, there is potential in wearable devices to allow for longer, less intrusive monitoring.

How to decrease your risk of stroke

With stroke, the best medicine is prevention. There are steps you can take to help prevent strokes.

To prevent strokes, it’s important to reduce your risk. Your best bet is to make healthy food choices, keep your weight down and exercise to avoid high cholesterol and high blood pressure, both of which increase your risk of stroke.

“If you have either high cholesterol or high blood pressure, the emphasis,” says Dr. Katzan, “is on controlling the problem.” In addition to making healthy choices, it’s important to follow your doctor’s treatment plan, she says.


Learn more about our editorial process.

Related Articles

Person in kitchen drinking glass of water
What It Means When You Have an MS Flare-Up

Some ‘flare-ups’ are temporary and expected, others can signal a need to change therapies

Silhouette of person, with brain as four puzzle pieces
The Mandela Effect: How False Memories Trick Your Brain Into Believing

Our collective misremembering of events comes from a surplus of false memories

Healthcare provider apply bandaid on patient's arm after a shot
What You Need To Know About MS and Vaccines

Most routine vaccines are safe for people living with multiple sclerosis — but be sure to talk with your care team about your needs

Silohuette of person, with light aimed at their eye and brain
June 20, 2024/Mental Health
Feeling Stuck? Brainspotting May Help

This alternative brain-body therapy focuses on unlocking pent-up feelings, memories and tension that may be stuck in your brain and body

Happy child sitting on stool in healthcare office, with toys around
How Common Is Autism?

Current research suggests 1 out of every 36 children in the U.S. has ASD — and that’s probably an undercount

Legs of healthcare provider and patient during rehabilitation
What Are the Differences in Left vs. Right Brain Strokes?

Strokes in the left side of the brain are more common and the effects are typically more noticeable

Close up of lion's mane mushroom growing on a tree
April 19, 2024/Nutrition
Health Benefits of Lion’s Mane Mushrooms

These trendy fungi may promote a healthy brain, heart and gut, but more research is needed to say for sure

Beef cut, chicken breast, cod filet and ground beef, with spices and seasoning
April 5, 2024/Nutrition
Are You Eating Enough Choline-Rich Foods?

This vital nutrient helps your brain and body in many ways — and most of us need more of it

Trending Topics

Female and friend jogging outside
How To Increase Your Metabolism for Weight Loss

Focus on your body’s metabolic set point by eating healthy foods, making exercise a part of your routine and reducing stress

stovetop with stainless steel cookware and glassware
5 Ways Forever Chemicals (PFAS) May Affect Your Health

PFAS chemicals may make life easier — but they aren’t always so easy on the human body

jar of rice water and brush, with rice scattered around table
Could Rice Water Be the Secret To Healthier Hair?

While there’s little risk in trying this hair care treatment, there isn’t much science to back up the claims