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Brain aneurysm or brain bleed

Also called: Brain aneurysm, brain bleed, subarachnoid hemorrhage

A bulge in a brain artery that can burst, causing a sudden worst-ever headache. It's an emergency.

SignThunderclap headache

Overview

Many brain aneurysms never burst. Burst aneurysms cause bleeding around the brain.

An aneurysm is a weak bulge in a brain artery.

If it bursts, it causes a sudden, severe headache.

Symptoms

Common signs:

  • Sudden worst headache of your life
  • Stiff neck
  • Passing out

Less common

  • Vomiting

When to get medical care

Call 911Call 911 now for: sudden worst headache of your life, stiff neck, passing out.
Get care todayMilder symptoms that could be early signs.
See a doctor soonQuestions about lowering your risk.

Causes

Weak artery.

Does it spread or run in families?

  • It isn't contagious. You can't catch it from someone else.

Who is more likely to get it

  • Smoking
  • High blood pressure

Diagnosis

This is diagnosed in the emergency room or hospital.

The exam

A physical exam.

Tests

Tests, if needed:

  • CT:

Treatment

Emergency care is needed. While waiting for help:

Self-care

  • Call 911
  • Control blood pressure

Prevention

To lower your risk or prevent problems:

  • Don't smoke
  • Limit alcohol

Which doctor treats this

  • Emergency doctors treat it first, in the ER.
  • They may send you to a neurologist (brain and nerve doctor) or a neurosurgeon.

Back to school, work, or sports

  • Recovery time varies. Ask your care team when you can drive, lift, work, and exercise.

Children, pregnancy, and older adults

  • Families: Some need screening.

Pregnancy and breastfeeding

  • If you're pregnant or planning to be, tell your prenatal provider about this condition.
  • Don't start or stop any medicine on your own. Some are safe in pregnancy and some need to be changed.
  • Ask before taking any pain reliever. The FDA advises avoiding ibuprofen and naproxen after 20 weeks unless your doctor says to.
  • Breastfeeding: Most medicines are fine, but ask. The NIH LactMed database lists what's known about each one.

For caregivers

  • Go to visits when you can and take notes.
  • Keep a list of medicines, allergies, and doctors in one place.
  • Learn the warning signs that need fast care.
  • Learn CPR. Many hospitals and the Red Cross offer classes.
  • Take breaks and ask for help. Caregivers need care too.

Outlook

Fast treatment improves survival.

Getting ready for your visit

Bring a list of your symptoms and medicines.

What to bring

  • A list of your medicines and supplements
  • Notes on when symptoms started and what makes them better or worse

Questions to ask

  • What follow-up care do I need?
  • How can I prevent this from happening again?

Research studies

Research studies test new ways to find and treat health problems. Some are looking for volunteers. Talk with your doctor before joining one.

Search ClinicalTrials.gov for studies on Brain aneurysm or brain bleed

Sources

Last updated 2026-11-12.