What is a brain aneurysm?

A brain aneurysm occurs when there is a bulge or ballooning in the cranial artery, which is a blood vessel in the brain. The cranial artery gets weak and starts to bulge or balloon out. When a brain aneurysm causes the cranial artery to weaken, it can leak or rupture. This can cause a hemorrhagic stroke (bleeding in the brain) which can lead to severe brain damage or death. When a brain aneurysm ruptures, it can quickly become a life-threatening condition. Medical treatment is required immediately in order to prevent any serious damage or death.

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Brain aneurysms are caused by a thinning of the artery walls. They can occur in both adults and children, but are more common among adults between the ages of 35 and 60. They are also more common in women than men. There are a number of risk factors that can cause thinning of the artery walls and increase a person’s risk for a brain aneurysm. Some risk factors develop over time, and some are present at birth.

The symptoms of brain aneurysms vary depending on whether the aneurysm is ruptured or unruptured. When people have a ruptured cerebral aneurysm, it is called a subarachnoid hemorrhage. In this case, people often complain of having a severe headache that is worse than any other headache they have ever experienced. Other symptoms of a ruptured cerebral aneurysm include nausea and vomiting, stiff neck or neck pain, blurred vision or double vision, pain above and behind the eye, dilated pupils, sensitivity to light, and loss of sensation.

With an unruptured cerebral aneurysm, there are not always symptoms. In fact, most are asymptomatic, especially when they are small. However, is someone has a large aneurysm, they may experience symptoms as a result of pressure being placed on the adjacent brain or nerves. Symptoms of an unruptured cerebral aneurysm include peripheral vision deficits, thinking or processing problems, speech complications, perceptual problems, sudden changes in behavior, loss of balance and coordination, decreased concentration, short-term memory difficulty, and fatigue.

Risk factors that develop over time include older age, smoking, hypertension (high blood pressure), arterioscerlosis (hardening of the arteries), drug abuse (usually cocaine), head injury, excessive alcohol consumption, blood infections, and lower estrogen levels after menopause in women.

Risk factors that are present at birth include inherited connective tissue disorders that weaken blood vessels, such as Ehlers-Danlos syndrome; polycystic kidney disease, an inherited disorder that results in fluid-filled sacs in the kidneys and usually increases blood pressure; abnormally narrow aorta; cerebral arteriovenous malformation, an abnormal connection between arteries and veins in the brain that interrupts the normal flow of blood between them; or a family history of brain aneurysm (usually a parent or sibling).

Brain aneurysms among children are four times as likely to present with subarachnoid hemorrhage versus without subarachnoid hemorrhage. A subarachnoid hemorrhage is a type of hemorrhagic stroke that happens when a ruptured brain aneurysm occurs in the space between the brain and the thin tissues covering the brain. If the bleeding does not stop, blood can leak into the cerebral spinal fluid which increases pressure on the brain, causes clots, and can damage or destroy brain cells.