A brain aneurysm is a weak or bulging area in a blood vessel in the brain. Many people have aneurysms without ever knowing it, and in most cases they don’t cause symptoms or problems. However, if an aneurysm leaks or ruptures, it can lead to a *hemorrhagic stroke*, which is a serious and life-threatening emergency.

One of the most important warning signs is a sudden, severe headache—often described as the worst headache of someone’s life. This can sometimes be a *“sentinel bleed,”* a small leak that happens before a major rupture. Other symptoms may include nausea, neck stiffness, blurred vision, or sensitivity to light. If these appear suddenly, it’s critical to seek emergency help immediately rather than waiting.

Unruptured aneurysms are often silent, but if they grow, they can press on nearby nerves. This may cause vision problems, pain around one eye, a drooping eyelid, or numbness and weakness. Risk factors include high blood pressure, smoking, heavy alcohol use, and certain genetic conditions like Ehlers-Danlos syndrome or polycystic kidney disease.

While not all aneurysms can be prevented, managing blood pressure, avoiding smoking, staying active, and maintaining a healthy lifestyle can reduce risk. The key takeaway is awareness—knowing the warning signs and acting quickly can make a life-saving difference.