An aneurysm can develop quietly for years without causing noticeable symptoms. But if an aneurysm grows, leaks, or ruptures, the situation can become life-threatening very quickly.

An aneurysm is a weakened area in the wall of an artery that bulges outward. Aneurysms can occur in different parts of the body, including the brain and the aorta, the body’s largest artery.

Knowing the warning signs can help you recognize when urgent medical attention is needed.

What Is an Aneurysm?

Think of an aneurysm as a weak spot in an artery wall that begins to balloon outward.

Some aneurysms remain small and stable and never cause symptoms. Others can enlarge and potentially rupture, causing severe internal bleeding.

Aneurysms can occur in several locations, but brain aneurysms and aortic aneurysms are particularly important because rupture can be a medical emergency.

1. A Sudden, Extremely Severe Headache

One of the most important warning signs of a ruptured brain aneurysm is a sudden, severe headache often described as a thunderclap headache.

It can come on abruptly and may feel dramatically different from an ordinary headache.

A ruptured brain aneurysm can cause bleeding around the brain, known as a subarachnoid hemorrhage. This is a life-threatening emergency.

Do not wait for the headache to improve on its own. Seek emergency medical care immediately.

2. Nausea and Vomiting

A sudden severe headache accompanied by nausea or vomiting can be another warning sign of bleeding around the brain.

These symptoms can occur with many less-serious conditions, so they don’t automatically mean an aneurysm has ruptured. But when they occur suddenly alongside an unusually severe headache, urgent evaluation is essential.

3. Stiff or Painful Neck

Neck stiffness or pain can occur following a subarachnoid hemorrhage.

If a stiff neck develops suddenly along with an explosive headache, vomiting, confusion, weakness, or other neurological symptoms, treat it as an emergency.

4. Changes in Vision

An unruptured brain aneurysm can sometimes cause symptoms by pressing on nearby structures.

Possible symptoms include:

• Double vision
• Blurred vision
• Loss of vision
• Pain around or above one eye

Persistent or unusual vision changes should be medically evaluated.

5. Weakness or Numbness

Sudden weakness or numbness—particularly on one side of the body—can occur when bleeding from a ruptured brain aneurysm affects the brain.

Facial drooping or difficulty moving an arm or leg are also emergency warning signs.

6. Trouble Speaking or Understanding

Sudden slurred speech, difficulty finding words, confusion, or difficulty understanding speech can signal a serious neurological emergency.

Don’t wait to see whether these symptoms disappear.

Call your local emergency service immediately.

7. Seizure, Fainting, or Loss of Consciousness

A ruptured brain aneurysm can cause seizures, reduced consciousness, fainting, or confusion.

These symptoms require immediate emergency medical attention.

Aortic Aneurysm Warning Signs

Aneurysms can also develop in the aorta.

Aortic aneurysms may cause no symptoms until they become large or rupture. Depending on their location, symptoms can include sudden severe chest or upper-back pain, shortness of breath, difficulty breathing or swallowing, or deep pain in the abdomen, back, or side.

A ruptured or dissected aorta can cause life-threatening internal bleeding and requires emergency treatment.

Who May Be at Higher Risk?

Risk varies depending on the type and location of the aneurysm.

For aortic aneurysms, important risk factors include:

• Smoking or a history of smoking
• High blood pressure
• High cholesterol
• Atherosclerosis
• Increasing age
• A family history of aneurysm
• Certain inherited connective-tissue conditions

For brain aneurysms, smoking, high blood pressure, family history, and certain inherited conditions can increase risk.

Can an Aneurysm Be Detected Before It Ruptures?

Sometimes.

Many aneurysms cause no symptoms and are discovered incidentally during imaging performed for another reason. When an aneurysm is found, doctors consider factors such as its location, size, symptoms, growth, and the person’s overall risk when deciding whether monitoring or treatment is appropriate.

This is why people with significant risk factors should discuss them with a healthcare professional rather than waiting for symptoms to appear.

When Is It an Emergency?

Seek emergency medical help immediately if someone suddenly develops:

• An extremely severe, sudden headache
• Weakness or numbness on one side
• Facial drooping
• Difficulty speaking
• Sudden vision loss or major visual disturbance
• Loss of consciousness
• A seizure
• Sudden severe chest, abdominal, or back pain

Don’t drive yourself to the hospital. Call your local emergency service.

Final Thoughts

Aneurysms can be frightening because many cause no warning symptoms before they become dangerous. However, recognizing the major emergency signs—especially a sudden, extremely severe headache or sudden severe chest, abdominal, or back pain—can be crucial.

Not every headache or pain indicates an aneurysm, but symptoms that appear suddenly and severely should never be dismissed.

When it comes to a possible aneurysm rupture, getting emergency medical attention quickly can make a critical difference.