An aneurysm is an abnormal bulge or ballooning in the wall of an artery which may be caused by damage to the blood vessel or weakness in the vessel walls. A saccular aneurysm looks like a small, irregular sack. While aneurysms may occur anywhere in the body, the most likely locations are the cerebrum, or brain, and the aorta, a large blood vessel that travels from the left ventricle of the heart, through the chest, carrying blood to the vital organs. As the aorta reaches the lower abdomen it branches into two smaller arteries which carry blood to the pelvis and legs.
A cerebral saccular aneurysm generally occurs in the circle of Willis area of the brain, in the middle cerebral artery. At one time, these were thought to be congenital, though studies now seem to contradict that assumption. There are some genetic abnormalities, such as autosomal dominant polycystic kidney disease (ADPKD), which are associated with intracranial aneurysms. A significant number of patients diagnosed with cerebral saccular aneurysm actually have multiple lesions, though this is much more likely to occur in females than in males.
The most common cause of cerebral aneurysms is hymodynamically induced degenerative vascular injury. Rare cases may also result from trauma, cocaine use, tumors or infection. Treatment is generally recommended, though the method depends upon the location of the lesion. Surgical methods include clipping the area, or an endovascular process called coiling.
A saccular aneurysm is most likely to form in the aorta, and the majority of these are abdominal. Men between the ages of 40 and 80 are most likely to develop abdominal aneurysms, usually as a result of atherosclerosis, or hardening of the arteries. An abdominal saccular aneurysm is unlikely to rupture if it develops slowly and does not become larger than one and one-half to two inches (4-5 cm). If the aneurysm grows faster or larger, then intervention is recommended. Surgical repair involves removing the weakened part of the artery and replacing it with a polyester tube.
Aortic aneurysms may also be thoracic, meaning they form above the diaphragm. These may occur in people who have connective tissue disorders or be caused by trauma, such as a car accident, prolonged high blood pressure, and previous tearing of the arterial walls. Surgical repair depends upon where the saccular aneurysm is located. If it is in the ascending aorta, which is located in the front near the heart, surgery is recommended if it reaches a size of about two inches (5 cm). If the lesion is in the descending aorta, surgery is generally delayed until the lesion is almost two and one-half inches (approximately 6 cm).
Aneurysms are considered silent killers because they can grow for years without presenting any symptoms. If symptoms do occur, they vary depending upon the location of the saccular aneurysm. An aortic lesion will generally not show any symptoms unless it becomes large enough to impede blood flow, press against other body parts, or rupture. If symptoms do occur, they will usually include a throbbing feeling in the abdomen or throbbing back or abdominal pain.
When a thoracic saccular aneurysm reveals symptoms, they usually involve pain in the back, neck or jaw, coughing, hoarseness and trouble breathing. Cerebral aneurysms can cause drooping eyes, double or blurred vision, dilated pupils and facial numbness. In all cases, a rupture is generally accompanied by sharp pain in the affected area. Nausea, vomiting, clamminess and a loss of consciousness follow. The internal bleeding can quickly bring on shock and death unless the patient receives immediate emergency medical attention.