Stroke vs Aneurysm (Differences and Similarities)

Reviewed on 4/21/2021

Are a stroke and an aneurysm the same thing?

No, a stroke and an aneurysm are not the same thing. They are two very different medical health problems. Stroke is a process or an event that happens in your body, while an aneurysm is a problem with a person’s anatomy (anatomical abnormality).

What is a stroke?

There are two major types of stroke – ischemic strokes and hemorrhagic strokes. Ischemic strokes occur when a blood vessel in the brain is blocked by a blood clot. The other type is a hemorrhagic stroke where a blood vessel leaks due to weakened blood vessel walls or due to damage by traumatic injury. The leaking vessels allow blood to leak into the brain tissue resulting in loss of blood to brain tissues, and because the leaked blood is under pressure, it can squeeze off other blood vessels that supply blood to other areas of the brain close to the blood vessel injury.

What is an aneurysm?

An aneurysm is a weakness in an artery wall that allows the artery to abnormally widen or balloon out. This anatomical feature can occur almost anywhere in the body, for example, cerebral aneurysms (brain aneurysms), aortic aneurysms, and splenic aneurysms and others. This article will only discuss brain aneurysms. An aneurysm is not a process like stroke but an anatomic abnormality.

Are the causes of a stroke and brain aneurysm the same?

No, the causes of these two conditions are very different.

Stroke causes

Strokes are caused when oxygen is cut off to brain cells. Ischemic stroke happens when a blood clot blocks an area in an arterial blood vessel in the brain. This type of stroke accounts for about 80% of strokes.

  • Ischemic strokes are caused by blood clots that form on the inside of the arteries or by a blood clot or cholesterol plaque fragment from elsewhere in the body (usually the heart).
  • A hemorrhagic stroke is due to blood leaking out of a brain artery into brain tissue. Because of this leakage, the brain receives less oxygen. And, because the blood is under pressure, the bleeding into adjacent brain tissue can compress other vessels and deprive areas next the injured blood vessel or artery (adjacent brain tissue) of oxygen. This type of stroke accounts for about 20% of strokes.

Brain aneurysm causes

A brain aneurysm may be caused by congenital (present at birth) blood vessel problems happen as a result of blood vessel disease over time, or result from injury and/or damage to the blood vessel. Almost all brain aneurysms have no symptoms until they begin to leak blood. When the aneurysm leaks blood, it is considered to be a cause of a hemorrhagic stroke and this is a medical emergency.

What are the differences between the symptoms and signs of stroke vs brain aneurysm?

Unless a brain aneurysm leaks or bursts open, there usually aren't any symptoms. However, if the aneurysm does leak or burst open, then signs and symptoms are the same for a stroke, which also is the cause of a hemorrhagic stroke. A very slow leak from a brain aneurysm may cause headaches or a large aneurysm may cause blurry vision, loss of vision, facial droop and possibly headaches.

The symptoms and signs for ischemic and hemorrhagic stroke are similar. The American Heart Association and the American Stroke Association emphasize four letters and three numbers to consider if a person is having a stroke. They suggest the following FAST system to recognize and treat strokes:

  1. F - facial drooping
  2. A - arm weakness
  3. S - speech difficulty
  4. T – time - do not delay call these three numbers – 911

Other symptoms may appear either separately or in combination with the above, and they all happen suddenly without warning:

  • Confusion
  • Numbness or weakness in the extremities, especially on one side of the body
  • Vision problems
  • Difficulty walking along with dizziness, lack of coordination and/or balance
  • Severe headache with no known cause
  • Seizures
  • Loss of memory
  • Trouble getting words out
  • Trouble typing, texting, or other problems with motor coordination

If you think someone is having a stroke or aneurysm call 911 immediately.

What is the treatment for these diseases?

Treatment for stroke is time-dependent and type dependent. If stroke symptoms are noticed, call 911 and have the patient taken to a stroke center, and don't give them aspirin. Once at the hospital, the patient will have a CT of the head to determine if the person has an ischemic or hemorrhagic stroke. This is very important because subsequent treatments are markedly different for these two types of stroke.

If the stroke is diagnosed as ischemic, the treatment may involve an IV infusion of a “clot-busting” drug (r-tPA or tissue plasminogen activator) to open the blood vessel. If the stroke is determined to be hemorrhagic, usually a neurosurgeon, neurologist and in some hospitals, and invasive neuroradiologist will be consulted to reduce or stop the bleeding and/or surgically decompress the blood clot. It’s important that the diagnosis between ischemic and hemorrhagic stroke is made - treating a hemorrhagic stroke with a clot-busting drug will increase bleeding and likely will cause the patient to die. In certain circumstances, there may be no effective acute treatment for a stroke.

Treatment of brain aneurysms that aren’t leaking (or have a very slow leak) varies from patient to patient, but usually involves supportive measures like reducing high blood pressure with medication under the care of a doctor or other health care professional.

However, other treatments such as endovascular treatments that place coils in the aneurysm to promote thrombosis that results in obliteration of the aneurysm and/or surgical therapy by clipping the base or bottom of the aneurysm, much like tying off the end of a balloon to prevent further expansion and/or any leaking. Your medical condition and advice from your team (primary care doctor, neurosurgeon, neurologist and/or interventional neuroradiologist) play significant roles in deciding what treatment course is best for you.

What is the prognosis for stroke and aneurysm?

The prognosis for an ischemic stroke is highly variable and depends on where the clot occurs in the brain, how long the clot remains before it is treated, and how effective the treatment is. Consequently, ischemic strokes may vary in prognosis from good to poor, depending upon the above conditions and how well the patient responds to treatment and/or rehabilitation. Hemorrhagic strokes more often have a poorer prognosis and have a higher mortality rate than ischemic strokes.

The prognosis for brain aneurysms is usually good as long as they don’t leak or burst open. Prophylactic treatment of brain aneurysms is still controversial because there is a chance that any attempt to use endovascular treatments or surgical clipping actually may cause aneurysm to begin bleeding. Some procedures have a mortality rate of 3%. If the brain aneurysm leaks, the prognosis is poor and mortality is high unless acute neurosurgical or neurointerventional treatment is successful.


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American Heart Association. "What Is an Aneurysm?" Jan. 22, 2021. <>.

National Stroke Association. "Types of Stroke and Treatment." <>.

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