Cryptogenic Stroke

What is a Cryptogenic Stroke?

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A cryptogenic stroke is a stroke of unknown cause. This means that the stroke cannot be attributed to any specific stroke cause or risk factor, even after thorough testing. Before labeling any stroke a cryptogenic stroke, your stroke team will search for the common and uncommon causes of stroke. The most common causes of stroke include smoking, heart disease, high blood pressure, vascular disease and high cholesterol.

What is a Stroke?

A stroke is brain damage due to interruption of blood flow to a region of the brain. It is among the top causes of death and disability in the United States. A stroke occurs when a blood vessel that carries oxygen and nutrients to the brain is either blocked by a blood clot or bursts (or ruptures). When that happens, part of the brain cannot get the blood (and oxygen) it needs, so the brain cells in that region may suffer permanent damage.

Effects of Stroke

The brain is an extremely complex organ that controls various body functions.  If a stroke occurs and blood flow can't reach the region that controls a particular body function, that part of the body won't work as it should.

Because the different areas of the brain all control specific functions, a stroke can cause any physical or cognitive (thinking) problem.

Most of the time, your medical team can effectively diagnose a stroke.

The next step is urgent stabilization of your medical condition and stroke treatment to minimize and damage from the stroke. 

Why is it Important to Figure Out the Cause of a Stroke?

A stroke can be caused either by a blood clot blocking the flow of blood to the brain (called an ischemic stroke) or by a blood vessel rupturing and preventing blood flow to the brain (called a hemorrhagic stroke).

 A TIA (transient ischemic attack), or "mini stroke", is caused by a temporary clot. 

If you have a TIA or an ischemic stroke, the list of causes is somewhat different from the causes of a hemorrhagic stroke. The reason that your medical team works so hard to search for and identify the cause of your stroke is that the cause can often be controlled and managed, substantially reducing your chances of having another stroke.

A stroke typically occurs as the result of years of buildup of disease in the blood vessels of the heart or the brain. Most people who experience a stroke are at high risk of having another stroke. Having one stroke causes a handicap, and having another stroke adds another handicap, which can significantly interfere with your daily life.

 

How Does Your Medical Team Search For the Cause of Your Stroke?

If you have had a stroke, you can expect a number of medical tests that examine the structure of your brain to see exactly where the stroke is located and what type of stroke it is. These tests include brain imaging tests, such as Brain MRI, Brain CT, Brain MRA and Brain MRV. It is unlikely that you would need to have too many of these imaging tests, because one test may give enough answers so that other tests are not needed.

When it comes to searching for the underlying cause of your stroke, your doctor may order any of a number of blood tests that examine your heart, your blood clotting tendency, your vitamin B12 level, and even your thyroid function. Again, you would not need to have all of these tests. Your doctor will decide which tests to order depending on your medical history, your family history, the type of stroke you had and the results of preliminary tests.

There are also some lifestyle factors that can add to your risk of stroke, such as smoking, a high fat diet, major stress and mood problems and lack of physical exercise. Less common causes of stroke include pregnancy or the use of birth control pills. Post-menopausal hormone therapy may pose special stroke risks for women and the use of testosterone therapy for men may increase the risk of stroke.

A Word From Verywell

If you have been told that you have had a cryptogenic stroke, you might be concerned about the chances of having another stroke. However, rest assured that, since you do not have a detectable medical condition, your chances of having a stroke are not as high as you might think.

Nevertheless, because you have already had a stroke, you should learn as much as you can about stroke prevention so that you can make the lifestyle changes necessary to prevent yourself from experiencing another stroke.

Sources:

CLINICAL PRACTICE. Cryptogenic Stroke, Saver JL, N Engl J Med. 2016 May 26;374(21):2065-74

Edited by Heidi Moawad MD

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