Carotid Aneurysm

A cerebral aneurysm (also known as intracranial or intracerebral aneurysm) is a weak or thin blood vessel in the brain that balloons and filled with blood. The bulging aneurysm can put pressure on a nerve or in the surrounding brain tissue. It may also leak or rupture, spilling blood into surrounding tissue (called a hemorrhage). Some cerebral aneurysms, especially those that are very small, do not bleed or cause other problems. Cerebral aneurysms can occur anywhere in the brain, but most are located along a loop of arteries that connect the underside of the brain and the skull base.

Cerebral aneurysms are pathologic focal dilatations of cerebrovasculature which are prone to rupture. These vascular abnormalities are classified by presumed pathogenesis. Saccular, berry, or congenital aneurysms constitute 90% of all cerebral aneurysms and are located at major branch points of large arteries. Dolichoectatic, fusiform aneurysms or atherosclerosis are elongated pockets of proximal arteries, which represent 7% of all cerebral aneurysms. Infectious or mycotic aneurysms are located in the periphery and comprise 0.5% of all cerebral aneurysms. Other peripheral lesions include neoplastic aneurysms, sequelae of rare fragments embolized tumor, and traumatic aneurysms.

A commonplace of cerebral aneurysms in arteries at the base of the brain called the circle of Willis. About 85% of cerebral aneurysms develop in the anterior circle of Willis, and involve the internal carotid arteries and their major branches that supply the anterior and middle sections of the brain. The most common sites are the anterior communicating artery (30-35%), the bifurcation of the internal carotid and posterior communicating artery (30-35%), the bifurcation of the middle cerebral artery (20%), the bifurcation of the basilar artery, and the remaining posterior circulation arteries (5%).

Most brain aneurysms are caused by a congenital abnormality in an artery wall. Cerebral aneurysms are more common in people with certain genetic diseases such as connective tissue disease and polycystic kidney disease, and certain circulatory disorders, such as arteriovenous malformation - congenital malformation in which a tangle of arteries growled and veins in the brain disrupts blood flow.

The signs and symptoms of an unruptured aneurysm will partly depend on brain size and growth rate. For example, a small unchanging aneurysm usually produces no symptoms, whereas a larger aneurysm that is steadily growing may produce symptoms such as loss of sensation in the face or problems with eyes. Just before an aneurysm ruptures, a person may experience symptoms such as sudden and severe headache, nausea, blurred vision, vomiting and unconsciousness.

Most aneurysms go unnoticed until they rupture. In about 10-15 percent of cases, however, there are symptoms. common signs include an enlarged pupil in an eye, a drooping eyelid, or pain above or behind the eye. Other symptoms include headache in a specific part of the head, difficulty walking, double vision, or numbness of the face.

Diagnosis of a ruptured cerebral aneurysm is usually made by finding signs of subarachnoid hemorrhage on a CT scan (Computed Tomography, sometimes called CAT scan). The scanner is a computerized test that rapidly X-rays in the body sections, or slices, as the body is moved by a large circular machine. If the scan is negative but a ruptured aneurysm is still suspected, a lumbar puncture is performed to detect blood in the cerebrospinal fluid (CSF) that surrounds the brain and spinal cord.