Aneurysm growth is not always predictable. Growth can increase the risk of rupture and bleeding into the brain, which can be life threatening. Because of this, people should work with a doctor to monitor aneurysms.
A brain aneurysm, also known as a cerebral aneurysm, is an abnormal and weakened area in the wall of a blood vessel within the brain. It resembles a balloon or bulge in the blood vessel.
This article looks at how brain aneurysms grow, signs of an aneurysm, and when to speak with a doctor.
Brain aneurysms do not always grow at a
Aneurysms at arterial bifurcations (branching points) in the brain may be more prone to growth due to the force of the blood flow, but this is not a rule that applies to all cases.
- Small: Less than 11 millimeters (mm) in diameter, which is roughly the same size as a large pencil eraser.
- Large: Between 11–25 mm in diameter, which is approximately the diameter of a dime.
- Giant: More than 25 mm across, which is larger than a quarter.
Doctors use medical imaging techniques, such as magnetic resonance angiography or computed tomography angiography, to monitor aneurysms over time.
The frequency of monitoring
Complications of a ruptured brain aneurysm can include:
- Subarachnoid hemorrhage (SAH): This is the
primarycomplication of a ruptured brain aneurysm. It occurswhen blood leaks into the space between the brain and the thin tissues that cover it, called the subarachnoid space.
- Vasospasm: Following an SAH, blood vessels in the brain may constrict and narrow, reducing blood flow.
- Cerebral edema: Swelling of brain tissue can
occurdue to irritation caused by blood in the subarachnoid space.
- Stroke: Brain damage from an interruption of blood supply in one or more areas of the brain can occur due to disruption of blood flow after an aneurysm rupture.
Learn about the potential causes of a ruptured brain aneurysm.
Whether or not an aneurysm grows over time can vary from person to person and even among different aneurysms within the same individual.
Given the unpredictable nature of aneurysm growth, doctors carefully
Sometimes, a doctor may surgically treat an unruptured brain aneurysm to help prevent rupturing. However, sometimes doctors will continue to observe aneurysms instead of surgically treating them.
Doctors do not know exactly what causes a brain aneurysm to form. Aneurysms typically begin with weakening in the walls of an artery in the brain. Several factors can increase the risk of this occurring, including:
- a family history of brain aneurysms
- certain genetic conditions, such as autosomal dominant polycystic kidney disease, Ehlers-Danlos syndrome, and Marfan syndrome
- high blood pressure
The risk of developing an aneurysm may also increase with age, with most aneurysms occurring in people
Most unruptured brain aneurysms
Ruptured brain aneurysms are a medical emergency and typically cause many symptoms.
Unruptured brain aneurysms
In some cases, unruptured aneurysms may produce mild or intermittent symptoms due to pressure on nearby areas in the brain. These symptoms can include:
- eye pain
- facial pain
- neck pain
- double vision
- eyelid drooping
- dropping of one side of the face
- numbness or weakness in the face or one side of the body
Ruptured brain aneurysm
A ruptured brain aneurysm is a medical emergency and can result in SAH, which is bleeding into the space surrounding the brain.
Other signs and symptoms of a ruptured brain aneurysm can include:
- loss of consciousness
- nausea and vomiting
- light sensitivity
- stiff neck
- vision changes, including blurry or double vision
People should seek immediate medical help if they or someone else experiences these symptoms.
If someone thinks they are at risk of a brain aneurysm, they should speak with a doctor. A doctor can assess a person’s risk and recommend appropriate monitoring or screening.
People should seek immediate emergency help if they or someone else experiences any of the symptoms of a ruptured brain aneurysm. This includes the following:
- a severe “thunderclap” headache
- loss of consciousness
- nausea and vomiting
- vision changes
- an altered mental state, including confusion
Aneurysms can vary in size and shape and may or may not grow over time. The growth rate of an aneurysm is unpredictable and varies among individuals.
Regular monitoring with medical imaging is essential to track aneurysm growth.
Small or unruptured aneurysms may be asymptomatic. However, a ruptured aneurysm is a medical emergency that requires prompt treatment.