A brain aneurysm is a bulge or ballooning in a blood vessel in the brain. It often looks like a berry hanging on a stem. A brain aneurysm can leak or rupture, causing bleeding into the brain (hemorrhagic stroke). A ruptured brain aneurysm most often occurs in the space between the brain and the thin tissues covering the brain. This type of hemorrhagic stroke is called a subarachnoid hemorrhage.

A ruptured aneurysm quickly becomes life-threatening and requires prompt medical treatment.

Most brain aneurysms don’t rupture, create health problems or cause symptoms. Treatment for an unruptured brain aneurysm may be appropriate in some cases and may prevent a future rupture.

A ruptured aneurysm quickly becomes life-threatening and requires prompt medical treatment. The primary symptom is a sudden, severe headache. The headache is sometimes associated with nausea, vomiting and a brief loss of consciousness. Untreated, a subarachnoid hemorrhage can lead to permanent brain damage or death.

Your surgeon may recommend endovascular treatment, such as embolization, in which a catheter is threaded into an artery to your brain, and a coil is guided through the catheter and placed in the aneurysm. Or, the surgeon will make an incision in your scalp, locate the hemorrhage and place a metal clip to stop the blood flow.

Most brain aneurysms, however, don’t rupture, create health problems or cause symptoms. Treatment for an unruptured brain aneurysm may be appropriate in some cases and may prevent a rupture in the future.