At a Glance

Q: What’s the difference between a stroke and an aneurysm?
A: A stroke is a sudden loss of blood flow to the brain; an aneurysm is a bulge in a vessel that can rupture. Both need fast action.

• Stroke symptoms appear suddenly: slurred speech, weakness.
• Aneurysms may go unnoticed until rupture.
• High blood pressure raises risk for both.

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Strokes. Aneurysms.
Both happen in the brain’s blood vessels. Both happen quickly. Both are scary.

But they’re very different. 

And those differences “could be the difference between life and death,” says Dr. Akil Patel. 

As a neurosurgeon uniquely dual-trained in two disciplines focused on the brain’s blood vessels, Dr. Patel has treated many patients who’ve suffered strokes or aneurysms. And he’s seen how recognizing the differences between the two conditions is crucial—and so are the seconds.

What makes a stroke a stroke?

A stroke happens when blood flow to the brain is interrupted, depriving brain cells of oxygen. Without oxygen, those cells begin to die within minutes. Every year, nearly 1 in 6 Americans experience a stroke, and roughly 795,000 Americans will have one in their lifetime, making it the fifth leading cause of death in the U.S.

There are two main types:

• Ischemic strokes, caused by a blockage—like a clot—that prevents blood from reaching parts of the brain. These account for nearly 9 out of 10 strokes.
  
• Hemorrhagic strokes, which are less common but often more severe. These occur when a blood vessel in the brain bursts, causing bleeding and increased pressure that damages surrounding tissue. 

In both, symptoms typically appear suddenly, including

• Slurred speech
• Weakness on one side
• Trouble seeing, walking, or understanding others

In hemorrhagic strokes, a sudden, intense headache can also be a red flag.

What sets an aneurysm apart?

Unlike a stroke, an aneurysm isn’t an event—it’s a condition. Also known as cerebral aneurysms, brain aneurysms are bulges or ballooning in a blood vessel in the brain. They often form when a vessel wall has weakened. These weakened areas can develop because of 

• Family history
• High blood pressure hypertension
• Smoking and drug use 

Aneurysms can go unnoticed for years. Dr. Patel shares that the Brain Aneurysm Foundation estimates that 6.7 million Americans have an unruptured brain aneurysm. Aneurysms form slowly, as blood vessels weaken or thin. And many never rupture. Others are discovered incidentally during scans for unrelated issues.

But if an aneurysm ruptures, it’s a medical emergency. In the U.S. alone, a brain aneurysm ruptures every 18 minutes. Globally, an estimated 500,000 people die each year from ruptured aneurysms—half are younger than 50. And they’re more common in women and older persons. 

Warning signs of rupture include

• A sudden, severe headache—often described as “the worst headache of my life”
• Nausea or vomiting
• Stiff neck
• Loss of consciousness

When a brain aneurysm ruptures, it causes bleeding around the brain (a subarachnoid hemorrhage), a specific type of hemorrhagic stroke. Even if it hasn’t burst, an aneurysm can cause other symptoms if it presses on nerves or brain structures, such as

• Vision changes
• Balance problems
• Dull pain behind the eyes

“These ‘less significant’ symptoms may not cause debilitating immediate effects, but they can be telltale signs of what’s to come,” says Dr. Patel. “In a sense, they’re early warnings—your chance to act before a rupture occurs. If something doesn’t feel right, it’s best to get it checked out.”

What you can do

Though strokes and aneurysms are different, both can often be prevented through healthy lifestyle choices.

High blood pressure is the most significant risk factor for each. Other risks include

• Smoking
• Heavy alcohol use
• Family history
• Certain genetic conditions

Choices that can help lower your risk include

• Get regular checkups with your primary care provider.
• Monitor and manage your blood pressure.
• Avoid tobacco use.
• Exercise regularly.
• Eat a heart-healthy diet.

And most importantly, if something feels wrong—don’t wait. Call 911 if someone suddenly experiences slurred speech, weakness on one side, confusion, or a violent headache.

“Remember that ‘time is brain’,” says Dr. Patel. “This holds true for strokes and for aneurysms. Early detection and treatment can be the difference not only between life and death, but between a favorable outcome and a grim prognosis.”

Stay attentive, act quickly

Aneurysms and strokes aren’t the same, but they can travel close together. Knowing how they differ won’t always change what you do in the moment—but it might help you recognize when that moment has arrived.

And when it has, seconds matter.