January 5, 2022

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.

Related Articles

blurred person looking out window in background with glass of wine and bottle in foreground
February 21, 2024
How Does Alcohol Affect Your Brain?

Even one drink can have an impact on your cognitive function leading to slurred speech, blurred vision and impaired memory

Caregiver and elderly male with head bent down
February 2, 2024
After Your Stroke: How To Handle 14 Common Complications

Your age, the type of stroke you had, the cause and the location can all impact your recovery

Hand holding magnifying glass examining the brain and data from a study.
June 19, 2023
What Is Cleveland Clinic’s Brain Study?

This first-of-its-kind study aims to identify biomarkers of neurological disorders

Dried Jujube fruit overflowing a white bowl on a wooden table.
May 25, 2023
What We Know (and Don’t Yet Know) About Jujube Fruit’s Benefits

Jujube is nutritionally dense, but research is limited

left and right half of brain making a light bulb
May 17, 2023
Left Brain vs. Right Brain: Are You Really One or the Other?

Different parts are responsible for different things, but you use both sides all the time

Mug of Coffee with Mushrooms
March 6, 2023
Mushroom Coffee: Is It Healthier Than Your Average Cup of Joe?

Mushroom coffee is expensive and has fewer health benefits than eating whole mushrooms

mandela effect brain memories
May 30, 2022
What Is the ‘Mandela Effect’?

Is it a multiverse or collective misremembering?

man on a diet eating salad
December 29, 2021
Weight Loss: How to Reset Your Brain for Success

How a dieting mindset keeps the weight on

Trending Topics

glass of cherry juice with cherries on table
Sleepy Girl Mocktail: What’s in It and Does It Really Make You Sleep Better?

This social media sleep hack with tart cherry juice and magnesium could be worth a try

Exercise and diet over three months is hard to accomplish.
Everything You Need To Know About the 75 Hard Challenge

Following five critical rules daily for 75 days may not be sustainable

Person in foreground standing in front of many presents with person in background holding gift bags.
What Is Love Bombing?

This form of psychological and emotional abuse is often disguised as excessive flattery