Sometimes, even with testing, the underlying cause of a stroke can’t be identified. When this happens, the stroke is classified as a cryptogenic stroke. These strokes make up about 25–40% of ischemic strokes.
Nearly
Ischemic strokes make up about
Hemorrhagic strokes are less common. They occur when a blood vessel ruptures, which can cause bleeding in your brain.
A stroke is called “cryptogenic” when the cause can’t be determined. Doctors classify strokes as cryptogenic in the following
- they can’t find the cause of the stroke
- the stroke has two or more possible causes
- the cause of the stroke hasn’t been fully evaluated
Read on to learn more about cryptogenic strokes, including how they’re diagnosed and treated.
Most strokes are ischemic and are caused by a blood clot that disrupts blood flow to part of your brain. Sometimes, even with testing, the cause of a stroke can’t be identified. In this case, the stroke is classified as cryptogenic.
It’s thought that a large proportion of cytogenic strokes are caused by:
- Atrial fibrillation (AFib): Atrial fibrillation (AFib) is a type of irregular heartbeat that increases your risk of stroke more than
5 times . - Hypercoagulable state: A hypercoagulable state occurs when your blood is more prone than usual to forming blood clots.
- Aortic arch atheroma: Aortic arch atheroma is a build-up of plaque inside the top of the main artery that leads away from your heart. A piece of this plaque can break off and reach your brain.
- Patent foramen ovale: Patent foramen ovale is a hole in your heart, present from birth, that doesn’t close entirely as you get older. This condition is present in about
25% of adults and usually doesn’t cause problems. - Other causes: rarer causes of cryptogenic stroke include:
- infections such as endocarditis
- a tear in the wall of one of your arteries
- cancer
Cryptogenic strokes make up
According to the
Symptoms of a stroke can vary depending on what area of the brain is affected.
- severe headache
- dizziness
- loss of balance
- lack of coordination
- vision changes or trouble seeing
- sudden confusion
- sudden difficulty speaking or understanding speech
- sudden paralysis, numbness, or weakness on one side of your body, including the:
- face
- arms
- legs
Learn more about stroke symptoms.
When to seek emergency medical attention
It’s critical to seek immediate medical attention, by calling 911 or local emergency services, if you believe you or someone you’re with is having a stroke. The faster treatment begins, the lower the risk of permanent brain damage will be.
Treatment is usually most effective if it’s initiated within
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According to the ASA, as many as
Doctors use many different tests to evaluate cryptogenic strokes and to look for the underlying cause.
An initial examination after your stroke usually includes:
- review of your medical history
- a physical exam
- noncontrast CT scan of your head
- 12-lead electrocardiogram, a painless test that measures the electrical activity of your heart
Further tests may be performed to examine the function of your heart and to look at the blood vessels in your brain.
Heart tests may include:
- 24-hour Holter heart monitor to continuously track your heart activity for 24 hours
- prolonged heart monitoring for longer than 24 hours
- transthoracic echocardiogram
- transesophageal echocardiogram
Imaging tests may include:
- brain MRI scan
- carotid ultrasound
- transcranial ultrasound
- computed tomography angiography of your head and neck
- magnetic resonance angiography of your head and neck
Additional tests that are performed on some people include:
- assessment for hypercoagulability (thick blood)
- artery and blood vessel disease tests
- cancer screening
Antiplatelet or anticoagulation therapy is recommended for
People who have certain health conditions, such as a blood disorder, diabetes, high blood pressure, or other conditions, may not be eligible for this treatment.
Antiplatelet therapy involves taking medications that stop blood cells, called “platelets,” from sticking together. Anticoagulation medications alter the proteins involved in the blood clotting process.
Finding the underlying cause of a stroke is important because it helps doctors know which type of treatment is most likely to be effective at preventing another stroke in the future. For example, cryptogenic strokes caused by AFib are more effectively treated with anticoagulation medications than antiplatelets.
What can you do to reduce your risk of another stroke?
According to a 2017 review, the 2-year reoccurrence rate of a cryptogenic stroke is quite high, around
- avoiding foods that are high in saturated fats, trans fats, and cholesterol
- limiting salt (sodium) intake
- maintaining a moderate weight
- exercising regularly
- quitting smoking, if you smoke
- limiting or avoiding alcohol
You may also be able to reduce your risk of another stroke by managing other underlying health conditions if you have them, such as:
- high LDL cholesterol
- high blood pressure (hypertension)
- diabetes
- atrial fibrillation (AFib)
- coronary artery disease
A transient ischemic attack (TIA) occurs when blood flow in your brain is temporarily disrupted. A TIA is also called a “ministroke.” TIAs can cause stroke-like symptoms, but the symptoms are temporary and typically last from a few minutes up to 24 hours.
A TIA isn’t the same as a cryptogenic stroke, but if you have a TIA with an unknown cause, the doctor may refer to it as a “cryptogenic TIA.”
Even though the symptoms may not last long, it’s very important to get immediate medical attention if you suspect you or somebody you know has had a TIA. Diagnosing and treating the underlying cause of a TIA may help lower the risk of a more serious stroke in the future.
A cryptogenic stroke is a stroke that has no identifiable cause. These strokes make up about
The symptoms of a cryptogenic stroke may include weakness or paralysis on one side of the body, dizziness, coordination issues, trouble speaking, and confusion.
It’s important to get immediate medical attention if you have any of these symptoms. The sooner you can get treatment, the higher the likelihood there is of a positive outcome.
To avoid another stroke in the future, it’s important that health professionals are able to diagnose the underlying cause of a stroke and prescribe the right treatment and preventive measures.
