An aneurysm is a bulging blood vessel in the brain. While most are harmless and cause no symptoms, a ruptured aneurysm is a life-threatening emergency that can lead to a hemorrhagic stroke.

Symptoms of a ruptured aneurysm include a sudden, severe headache (“the worst headache of my life”), blurred vision, nausea, fainting, drooping eyelid, stiff neck, light sensitivity, and seizures. If these occur, call emergency services immediately—time is critical.

Leaking aneurysms, or sentinel bleeds, may cause severe headaches over several days before a full rupture. These also require urgent medical attention.

Unruptured aneurysms often go unnoticed but can sometimes press on nerves, causing blurred vision, pain around one eye, a drooping eyelid, or a dilated pupil. Changes in headache patterns may also be a sign.

If you notice any of these symptoms, seek medical advice. Many aneurysms don’t need treatment, but early detection is key to preventing serious outcomes.