A brain aneurysm can be very dangerous, especially if it ruptures. The rupture risks life-threatening bleeding and has a high chance of causing severe disability or death, underscoring why prompt medical evaluation for concerning symptoms is crucial. Direct answer

• Immediate danger: A ruptured brain aneurysm causes a hemorrhagic stroke (a subarachnoid hemorrhage) with a sudden, severe headache often described as the worst of life, along with possible loss of consciousness, nausea, stiff neck, and other neurological symptoms. It is a medical emergency with substantial mortality and risk of permanent brain damage.

• Unruptured aneurysm: Many never rupture and may be monitored, but some can grow or press on nearby structures, potentially causing symptoms or increasing rupture risk over time. Decisions about monitoring vs. treatment depend on size, location, patient age, and overall risk factors.

• Outcomes after rupture: Among those who survive rupture, a large share suffer permanent neurological deficits, and about half may die, especially without rapid treatment. These outcomes emphasize the high stakes of rupture and the importance of urgent care if rupture is suspected.

Key points to discuss with a clinician

• If you or someone experiences a sudden, severe headache, often described as the worst ever, with possible neck stiffness, confusion, vision changes, or fainting, seek emergency care immediately. This could be a ruptured aneurysm.

• Regular risk assessment for unruptured aneurysms (e.g., via imaging if indicated by symptoms or family history) can guide decisions about observation vs. preventive treatment.

• Treatments (e.g., surgical clipping or endovascular coiling) aim to prevent rupture and are tailored to aneurysm characteristics and patient factors. Early intervention generally improves outcomes in appropriate cases.

If you’d like, I can tailor this to your specific situation (age, symptoms, family history, or known aneurysm) and provide sources adapted to your language and region.