First: I am not a medical doctor nor should this be taken as medical advise.
What is a brain aneurysm?
A brain aneurysm is a weak or thin spot on a blood vessel wall in the brain that balloons out and fills with blood. Often this wall is weakened by disease, injury or an abnormality present at birth. Aneurysms are not always life-threatening, but serious consequences can result if one bursts (ruptures) in the brain, spilling blood into the surrounding tissue. Rupture can cause serious complications including stroke, permanent nerve damage, or death. After rupture, an aneurysm may burst again and re-bleed into the brain, and additional aneurysms may also occur. More commonly, rupture may cause a subarachnoid hemorrhage—bleeding into the space between the skull bone and the brain. A serious complication of subarachnoid hemorrhage is hydrocephalus, in which the excessive buildup of cerebrospinal fluid in the skull ultimately leads to dangerous swelling and pressure on the brain.
What causes brain aneurysms?
Most aneurysms are acquired. However, they are more common in people with certain genetic diseases, such as connective tissue disorders and polycystic kidney disease, and certain circulatory disorders. Other causes include trauma or injury to the head, high blood pressure, infection, tumors, atherosclerosis (a blood vessel disease in which fats build up on the inside of artery walls) and other diseases of the vascular system, cigarette smoking, and drug abuse.
What types are out there?
Fusiform aneurysms are less common. They consist of an outpouching of the arterial wall. There is no stem.
Saccular aneurysms are the most common type of aneurysm. They are also known as “berry-aneurysms” because of their shape. They consist of a neck, a stem, and a dome.
What are the symptoms?
Most cerebral aneurysms do not show symptoms until they either become very large or burst. Small, unchanging aneurysms generally will not produce symptoms, whereas a larger aneurysm that is steadily growing may press on tissues and nerves. Table 1 provides a list of symptoms that a patient may experience.