What are the warning signs of a brain aneurysm?

Explains the key symptoms of a brain aneurysm rupture, what unruptured aneurysms can cause, and when to seek urgent medical help.

What is a brain aneurysm?

A brain aneurysm is a weak spot in a brain artery that can balloon out. Most never cause problems, but a rupture can lead to a serious bleed called a subarachnoid haemorrhage (SAH).

What are the warning signs of a bleed?

The classic warning sign is a sudden, very severe headache that reaches maximum intensity within minutes. Many people describe it as the “worst headache” they have ever had. Nausea or vomiting, neck stiffness, light sensitivity, fainting, seizures, or sudden problems with speech, sensation or movement can also occur.

Can a thunderclap headache be benign?

Yes. About 40% of people with a thunderclap headache have a benign cause. Even so, SAH must be ruled out urgently because a rupture can be life-threatening.

What symptoms can an unruptured aneurysm cause?

Most unruptured aneurysms cause no symptoms. If large or growing, they may press on nearby structures and cause pain behind the eye or double vision due to pressure on eye movement nerves.

What should I do if I have these symptoms?

Call emergency services immediately if you develop a sudden, extremely severe headache or any of the symptoms above. Early assessment and treatment save lives.

Key takeaways

• A sudden, worst-ever headache needs urgent medical assessment.
• Other warning signs include neck stiffness, vomiting, fainting, seizures and sudden weakness or speech problems.
• Most unruptured aneurysms are silent, but large ones can cause pain behind the eye or double vision.