Aneurysm

An aneurysm is an abnormal out-pouching or ballooning of an artery in the brain.  A given patient may have one or many of these.  They resemble a berry on a vine, and have been called berry aneurysms.

The presence of an aneurysm usually comes to medical attention when it bursts, an unfortunate tendency of these structures.  When an aneurysm bursts, it causes subarachnoid hemorrhage (SAH), or bleeding into the brain.  SAH is a very serious life-threatening condition that leads to death 40% of the time.  With rapid and accurate care, a patient may escape harm from SAH and go on to lead a normal life.

Less often an aneurysm is found for different reasons, and is then called unruptured.

Once an aneurysm ruptures, it must be operated on immediately.  Surgery is done to close off the opening into the aneurysm, by placing a clip across the neck (or stem of the berry), or by packing it with coils via a catheter from within the artery itself.  These procedures functionally removes the aneurysm from the circulation,  thereby preventing it from ever bleeding again.

There is controversy as to whether to treat unruptured aneurysms, but in most cases it should be done