An aneurysm is a balloon-like bulge or weakening of an arterial wall in the brain. An unruptured aneurysm is typically asymptomatic, unless it grows large enough to press on nearby tissues and nerves, or ruptures.
What Is An Unruptured Aneurysm?
An aneurysm is a balloon-like bulge in an artery of the brain, the result of a weak or thin spot in the arterial wall. If the aneurysm is small, it typically will not bleed or cause other problems. If it continues to grow larger, however, the arterial wall can become progressively thinner and weaker. An enlarged aneurysm also may put pressure on the surrounding brain tissue and nerves. If the wall becomes so thin and weak that the artery can no longer withstand the pressure of the blood flowing through it, the aneurysm can rupture. This releases blood into the brain, which can lead to very serious complications such as subarachnoid hemorrhage (SAH), hemorrhagic stroke, nerve damage, and/or death.
According to the National Institute of Neurological Disorders and Stroke, an aneurysm can occur in anyone, at any age. The condition are more common in adults than children (typically diagnosed between ages 35 and 60) and slightly more prevalent in women than men. Cerebral aneurysms can occur anywhere in the brain, but are most frequently develop in the arteries that extend from the underside of the brain to the base of the skull.
What Causes An Aneurysm?
Most cerebral aneurysms are congenital, the result of an inborn abnormality. People with a family history of aneurysm are more likely to develop the condition, as are those with certain genetic disorders that affect the body’s connective tissue and circulatory system, such as Marfan’s syndrome, Ehlers-Danlos IV, neurofibromatosis, and polycystic kidney disease.
Other potential causes include head injury, infection, high blood pressure, metastatic tumors of the head and neck, and atherosclerosis (fatty buildup along inner artery walls). Cigarette smoking and drug abuse, particularly the use of cocaine, can inflame blood vessels and contribute to aneurysm development. Some research has proposed a link to the use of oral contraceptives.
What Are The Symptoms?
Most aneurysms are asymptomatic, unless they rupture or grow large enough to press on the surrounding tissues and nerves. Symptoms of an unruptured aneurysm include:
- Double vision
- Dilated pupils
- Pain above and behind the eye
- Numbness, weakness or paralysis on one side of the face
- A new, unexplained headache (rare)
Symptoms of a ruptured aneurysm include:
- Sudden onset of a very severe headache (typically described as “the worse headache of my life”)
- Nausea/vomiting
- Stiff neck
- Light sensitivity/drooping eyelid
- Double vision/loss of vision
- Loss of consciousness/seizure
If you experience any symptoms associated with a ruptured aneurysm, please call 911 immediately.
How Is An Unruptured Aneurysm Diagnosed?
Most people are not aware they have an aneurysm, unless it bursts or enlarges to the point they start experiencing the neurological signs outlined above. Aneurysms are also frequently diagnosed when a patient undergoes brain imaging for another medical condition.
If you experience symptoms and your doctor suspects an aneurysm, he or she will do additional testing to gain more information about your condition and the most appropriate treatment. These tests can include:
- Angiography, which involves the injection of contrast dye into the arteries or veins. A cerebral angiogram can detect changes in artery walls, such as narrowing, weakness, and obstruction, and can pinpoint the abnormality’s exact location, size and shape.
- Computed tomography (CT), a noninvasive diagnostic tool in which X-rays of the head are taken and processed as two-dimensional cross-sectional images to reveal the presence of a cerebral aneurysm and, in the event the aneurysm has ruptured, where blood has leaked into the brain. CT angiography involves injecting contrast dye prior to scanning for sharper, more detailed images of blood flow within the brain.
- Magnetic resonance imaging (MRI) is another noninvasive imaging technique that involves using magnetic field and radio waves to create high-resolution, cross-sectional images of the soft tissues of the brain. Like the CT scan, a magnetic resonance angiogram (MRA) involves the use of contrast dye to reveal very detailed images of blood vessels and other structures of the brain.
- If a ruptured aneurysm is suspected, a cerebrospinal fluid analysis may be ordered to detect any bleeding or brain hemorrhage. This diagnostic procedure involves drawing a small amount of cerebrospinal fluid from the subarachnoid space with a surgical needle. The subarachnoid space is the space between the spinal cord and the membranes that surround it, and cerebrospinal fluid protects the brain and spinal cord.
How Is An Unruptured Aneurysm Treated?
Deciding when or how to treat an unruptured aneurysm involves weighing the risk of rupture versus the risks/benefits of treatment. Additional considerations include the type, size, and location of the aneurysm; risk factors such as smoking and alcohol or drug use; and the patient’s age, medical history, and overall general health.
In the case of an unruptured aneurysm, observation may be most appropriate. If you have an aneurysm that is small, intact, and asymptomatic, your doctor may monitor your condition with periodic imaging scans and work with you to reduce any risk factors you may have – treating an underlying medical condition, for example, or prescribing medication and/or lifestyle changes to help you stop smoking or control high blood pressure.
To treat aneurysms that warrant more serious intervention, there are several options available, two of which are surgical and one that is less invasive.
Microvascular clipping involves placing a small clip across the neck of the aneurysm to cut off the flow of blood to the aneurysm. In this procedure, the surgeon removes a section of skull, locates the blood vessel that feeds the aneurysm, and places the clip, which remains in place permanently to prevent future bleeding.
A related procedure, occlusion, may be recommended in instances where surgical clipping is not possible or the artery too damaged. Unlike clipping, which cuts off blood flow only to the aneurysm, this procedure involves blocking the blood supply to the entire artery in which the aneurysm is located. The procedure also may be accompanied by a bypass, which involves surgically grafting a small blood vessel to the occluded artery, to reroute blood flow around the damaged artery and aneurysm.
A nonsurgical alternative is endovascular embolization (coiling), which involves snaking tiny coils through a catheter into the aneurysm to block it from circulation. In this procedure, the surgeon inserts a catheter into the patient’s groin and, using fluoroscopic X-ray imaging, guides it through the arteries to the aneurysm. Tiny platinum coils, about a hairs-breadth or less in diameter, are threaded through the catheter and deployed into the aneurysm, blocking blood flow into the aneurysm and preventing rupture. The coils are made of soft platinum so that they are visible via X-ray and flexible enough to conform to the aneurysm’s shape.
Recovery for patients who undergo endovascular surgery for the treatment of an unruptured aneurysm is typically faster than those who undergo surgery; however, recovery times for either of these options is quicker than that of patients who undergo treatment for an aneurysm that has ruptured. Discuss your condition thoroughly with your doctor, and rely on his or her judgment regarding the type of treatment that is most appropriate.