Brain Aneurysm - Basics

Being diagnosed with a brain aneurysm is frightening.

Having survived a ruptured aneurysm is a challenging experience to have gone through and can be highly unsettling. Gathering information about your condition can help ease this fear, help begin the healing process, and help bring a sense of comfort and support during a trying time.

Take the first step by reading the information below. Then, follow the links to learn more.

What is a brain aneurysm?

A brain aneurysm is a weak bulging spot on the wall of a brain artery, like a thin balloon or a weak spot on an inner tube. Aneurysms form silently from wear and tear on the arteries and sometimes can form from injury, infection, or inherited tendencies.

What are the two types of aneurysms?

Saccular

• Most common type of aneurysm
• Also known as a “berry” aneurysm because of its shape
• It has a neck and stem

Fusiform

• Less common type of aneurysm
• An out-pouching of an arterial wall on both sides of the artery
• Does not have a stem

Factors doctors and researchers believe contribute to the formation of brain aneurysms:

• Smoking
• Hypertension
• Traumatic Head Injury
• Use of Alcohol
• Use of Oral Contraceptives
• Family History of Brain Aneurysms
• Other Inherited Disorders: Ehler’s Syndrome, Polycystic Kidney Disease, and Marfan’s Syndrome

An aneurysm is often diagnosed using various imaging equipment. Whether someone was brought to the hospital unconscious from a rupture or is waiting to undergo treatment for an unruptured aneurysm, similar detection methods pinpoint the location, size, type, and any other characteristics of the aneurysm that will help the doctors make the best decisions about how to proceed.

Detection Methods

CT Scan (Computed Tomography)

This scan takes a picture of your brain. It is fast and painless. You lie on your back, very still, while you are pushed into a large, tubular machine that creates the images. The test shows whether any blood has leaked around or into the brain.

CTA (Computed Tomographic Angiography)

In some cases, doctors may choose to perform a CT angiography. This test combines a regular CT scan with a contrast dye injected into a vein. Once the dye is injected into a vein, it travels to the brain arteries, and images are created using a CT scan. These images are enhanced because they show precisely how fluid (blood or dye) flows into the brain arteries, alerting doctors to a potential aneurysm or rupture.

MRI (Magnetic Resonance Imaging)

An MRI is a safe, painless diagnostic scan that examines various areas of your body, in this case, your head. Using a large doughnut-shaped magnet and a computer, magnetic signals are seen through a computer as radio waves. The computer can transform these radio waves into images. An MRI helps locate the aneurysm.

MRA (Magnetic Resonance Angiography)

This scan combines a regular MRI with the contrast dye injected into a primary vein. Like the CTA, this dye travels to the brain arteries, creating images using an MRI. This creates a more enhanced image.

Angiogram (Arteriogram)

This test allows doctors to see the size, shape, and location of the aneurysm and reveal any bleeding or vasospasm.

A small incision is made on one side, or both sides, of your groin after it is locally numbed and prepped. Then, a thin tube (catheter) is threaded through arteries from the groin to the neck. A contrast dye is injected and travels to the brain arteries. X-rays show all your arteries and any abnormalities, such as an aneurysm. Risks are involved, which will be explained to you and/or your family before the procedure.

Not all brain aneurysms rupture. Doctors are now able to detect unruptured brain aneurysms more frequently. An unruptured brain aneurysm may or may not cause symptoms. They are no less frightening or life-altering but require different diagnostic questions and potential treatments.

Things doctors consider in deciding whether or not to treat an unruptured aneurysm:

• Risk of Hemorrhage—Is it probable or not that the aneurysm will rupture?
• Size and Location
• Age and Health of the Patient
• Family History—Is there a family history? Have any of those aneurysms ruptured?
• Surgical Risks

If the unruptured aneurysm is treated, the recovery period is usually shorter for survivors than for people who have ruptured brain aneurysms. Although survivors may suffer many of the same physical and emotional symptoms as ruptured survivors, they will have a shorter hospital stay, require less rehabilitative therapy, and return to work more quickly.

Subarachnoid Hemorrhage

When a brain aneurysm ruptures, it causes bleeding into the compartment surrounding the brain, the subarachnoid space, causing a subarachnoid hemorrhage (SAH). Often, the aneurysm heals over, the bleeding stops, and the person survives. In more serious cases, the bleeding may cause brain damage with paralysis or coma. In the most severe cases, the bleeding leads to death.

Statistics

50% of those people die within minutes of a massive hemorrhage. Of the 50% who survive, half will suffer delayed death. The remaining survivors, depending upon the level of hemorrhage, usually live with severe long-term deficits.

Once a hemorrhage has occurred, several consequences might develop.

What Happens to the Brain When an Aneurysm Bleeds?

In most cases, after a rupture, the bleeding quickly stops. However, if leaked blood touches brain cells, these cells may become damaged. Blood in the cerebrospinal fluid (CSF) increases the pressure on the brain.

Damage to Brain Cells

Blood from an Aneurysm can leak into the CSF (cerebrospinal fluid) in the space around the brain (subarachnoid space). The pool of blood forms a clot. Blood can irritate, damage, or destroy nearby brain cells. This may cause problems with body functions or mental skills.

Fluid Buildup in the Brain

Blood from a torn aneurysm can block CSF circulation, leading to fluid buildup and increased pressure on the brain. The open spaces in the brain, called ventricles, may enlarge, causing hydrocephalus. This condition can make a patient lethargic, confused, or incontinent. Fluid may also build up in the brain after surgery. To stop fluid buildup, a drain may be placed in the ventricles, removing leaked blood and trapped CSF.

Narrowing of Nearby Arteries

The blood sprayed around the base of the brain can also produce a problem called vasospasm. Vasospasm typically develops 5-8 days after the initial hemorrhage. Narrowing of the blood vessels can occur, and at times, not enough blood is supplied to the brain, and a stroke may result. Blood pressure is often elevated with medicines to treat vasospasms. Certain medications are also given to try to ease vasospasm. Finally, catheters can be introduced inside the artery to use balloons or medicines delivered to the vessel directly to open up these narrowed vessels. Vasospasm does relax over several days.

Hydrocephalus

Because blood is sprayed around the base of the brain, the possibility of fluid buildup exists, causing hydrocephalus (picture b). The fluid buildup in the brain is often treated with a tube inserted into the fluid-filled space of the brain (the ventricle). The tube, called a ventriculostomy, frequently drains into a bag at the patient’s bedside.

Vasospasm

The blood sprayed around the base of the brain can also produce a problem called vasospasm. The blood vessels narrow, and at times, not enough blood can be supplied to the brain, and a stroke may result. Blood pressure is often elevated with medicines to treat vasospasms. Certain medications are also given to try to ease vasospasm. Certain medications are given to reduce the threat of vasospasm. This threat lessens over several days.

Treatment

Blood sprayed around the base of the brain can also cause vasospasm. Depending on the severity of the rupture and other factors, ruptured aneurysms can heal and be treated. Click on treatment to learn about the surgical and non-surgical procedures used to treat them.

Outlook

SAH survivors usually have a much longer recovery time than unruptured aneurysm patients, as well as more serious deficits. Symptoms are proportional to the degree of hemorrhage. Patients who are comatose or semi-comatose after a hemorrhage have longer recoveries and have more significant neurocognitive problems as compared to patients with more minor hemorrhages or unruptured aneurysms