Aneurysm: Symptoms You Shouldn’t Ignore

An aneurysm can exist quietly inside the body for years without causing any noticeable symptoms. In some cases, it is discovered accidentally during an imaging test performed for another reason. But if an aneurysm grows, leaks, or ruptures, the situation can become a medical emergency.

The image above illustrates a brain aneurysm, also called a cerebral or intracranial aneurysm. This occurs when a weakened area of a blood-vessel wall in or around the brain bulges outward, creating a balloon-like swelling.

Not every brain aneurysm ruptures, and many never cause symptoms. However, knowing the warning signs can be extremely important because a ruptured aneurysm can cause subarachnoid hemorrhage, a form of bleeding around the brain that requires immediate medical attention.

What Exactly Is an Aneurysm?

An aneurysm develops when part of an artery becomes weakened and begins to bulge.

Think of an artery as a flexible tube carrying blood under pressure. If a section of the vessel wall becomes weaker than the surrounding tissue, pressure from the blood can cause that area to expand.

Aneurysms can develop in different parts of the body, including the:

• Brain
• Aorta
• Abdominal arteries
• Other major blood vessels

The symptoms depend heavily on the aneurysm's location, size, and whether it has leaked or ruptured.

Brain Aneurysms May Cause No Symptoms

One of the most important things to understand is that an unruptured brain aneurysm often produces no symptoms at all.

Some are discovered unexpectedly when a person undergoes CT, MRI, or other imaging for an unrelated reason.

However, a larger aneurysm can sometimes press against nearby nerves or brain structures.

Depending on its location, possible symptoms may include:

Pain around or behind the eye

Changes in vision

Double vision

A drooping eyelid

Numbness or weakness involving part of the face

Difficulty moving an eye normally

Headache

These symptoms are not specific to aneurysms and can occur with many other conditions. But new or unexplained neurological symptoms deserve medical attention.

The Most Important Warning Sign: A Sudden Severe Headache

A ruptured brain aneurysm can cause a sudden and extremely severe headache.

People often describe this as a “thunderclap headache”—a headache that reaches maximum intensity very quickly.

It may feel dramatically different from a person's usual headaches.

A ruptured aneurysm can also cause:

• Nausea and vomiting
• Neck stiffness
• Sensitivity to light
• Loss of consciousness
• Confusion
• Seizures
• Weakness or numbness
• Difficulty speaking
• Vision problems

A sudden, severe headache—particularly one that is unlike previous headaches—should not be ignored or treated as an ordinary headache at home.

It can be a sign of bleeding in or around the brain and requires emergency evaluation.

Why a Ruptured Aneurysm Is So Dangerous

When a brain aneurysm ruptures, blood can escape from the artery into the space surrounding the brain.

This is known as subarachnoid hemorrhage.

Blood accumulating in this space can increase pressure around the brain and interfere with normal brain function.

The consequences can include permanent neurological injury, disability, or death.

The seriousness of the condition is why rapid diagnosis and treatment are so important.

A person with symptoms suggesting a ruptured aneurysm should receive emergency medical care immediately.

Aneurysm Symptoms Aren't Always Dramatic

Not every aneurysm produces obvious warning signs.

Some people may experience subtle symptoms before a rupture, particularly if the aneurysm is large enough to put pressure on nearby structures.

For example, a person might notice a new headache pattern, visual changes, or problems involving an eye.

But these symptoms can have many other explanations.

This is why it is not possible to diagnose an aneurysm based solely on symptoms.

Doctors may use imaging such as CT angiography, MR angiography, or cerebral angiography when an aneurysm is suspected.

Who Is More Likely to Develop a Brain Aneurysm?

Several factors can increase the likelihood of developing a cerebral aneurysm.

These include:

Smoking

Cigarette smoking is an important modifiable risk factor associated with both aneurysm formation and rupture.

High Blood Pressure

Long-term uncontrolled hypertension places additional stress on arterial walls and is associated with an increased risk of aneurysm rupture.

Family History

People with certain family histories of brain aneurysms may have a higher risk.

Age

Brain aneurysms can occur at different ages, but risk patterns change as people get older.

Certain Genetic Conditions

Some inherited disorders are associated with an increased risk of intracranial aneurysms.

Importantly, having a risk factor does not mean that a person definitely has an aneurysm.

What About Other Types of Aneurysms?

Not all aneurysms occur in the brain.

An aortic aneurysm, for example, develops in the body's largest artery.

An abdominal aortic aneurysm may cause no symptoms until it becomes large or ruptures.

Possible symptoms can include abdominal or back pain, although symptoms vary.

A ruptured aortic aneurysm can cause sudden severe pain, weakness, dizziness, fainting, and shock.

Like a ruptured brain aneurysm, this is a medical emergency.

Can an Aneurysm Be Prevented?

Not every aneurysm can be prevented because some risk factors—including genetics and age—cannot be changed.

However, several lifestyle measures can reduce important vascular risk factors.

Do not smoke.

Keep blood pressure under control.

Exercise regularly according to your health status.

Maintain a healthy weight.

Eat a balanced diet.

Limit excessive alcohol consumption.

Follow prescribed treatment for hypertension and other cardiovascular conditions.

These measures support overall blood-vessel health even though they cannot guarantee that an aneurysm will never develop.

What Happens If Doctors Find an Unruptured Aneurysm?

Finding an aneurysm does not automatically mean that surgery is required.

Doctors consider several factors, including:

• Size
• Location
• Shape
• Growth over time
• Previous bleeding
• Family history
• Age and overall health
• Other individual risk factors

Some small aneurysms may be monitored with periodic imaging.

Others may require treatment because the estimated risk of rupture is considered significant.

Potential treatments include surgical clipping and endovascular procedures, such as coiling or the use of flow-diverting devices.

The appropriate approach depends on the individual case.

When Should You Seek Emergency Help?

Certain symptoms should never be ignored.

Call emergency medical services immediately if someone develops:

• A sudden, extremely severe headache
• Loss of consciousness
• A seizure
• Sudden weakness or numbness
• Sudden difficulty speaking
• Sudden severe vision problems
• Confusion accompanying an abrupt neurological change
• Severe headache accompanied by neck stiffness, vomiting, or collapse

Do not drive yourself if you are experiencing severe neurological symptoms.

Rapid assessment can be critical when bleeding in the brain is a possibility.

Don't Confuse an Ordinary Headache With an Aneurysm

Headaches are extremely common, and most are not caused by brain aneurysms.

Tension headaches, migraines, dehydration, lack of sleep, infections, and many other conditions can cause head pain.

The warning sign that deserves particular attention is a headache that is sudden, unusually severe, and distinctly different from your normal headaches, especially when accompanied by neurological symptoms.

That is why context matters.

The goal isn't to become frightened by every headache. It is to recognize a potentially dangerous pattern when it occurs.

The Bottom Line

A brain aneurysm can remain completely silent, which is why some are discovered only through medical imaging. Others can produce symptoms by pressing on nearby nerves or structures.

The most important emergency warning sign is a sudden, severe “thunderclap” headache, particularly when it occurs with vomiting, neck stiffness, loss of consciousness, seizures, vision changes, weakness, confusion, or difficulty speaking.

A ruptured aneurysm is a medical emergency.

At the same time, not every headache or neurological symptom means that an aneurysm is present.

The best approach is to understand the warning signs without assuming the worst. Control modifiable risk factors such as smoking and high blood pressure, know your family medical history, and seek medical attention promptly for sudden or severe neurological symptoms.

When it comes to a possible brain hemorrhage, waiting to see whether the symptoms disappear can be dangerous. If a sudden, severe, unusual headache occurs, treat it as an emergency and seek immediate medical care.