Dr. Ben Wedro practices emergency medicine at Gundersen Clinic, a regional trauma center in La Crosse, Wisconsin. His background includes undergraduate and medical studies at the University of Alberta, a Family Practice internship at Queen's University in Kingston, Ontario and residency training in Emergency Medicine at the University of Oklahoma Health Sciences Center.
Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.
Blood to the brain is supplied by four major blood vessels that join
together at the Circle of Willis at the base of the brain. Smaller branch
arteries leave the circle to supply brain cells with oxygen and nutrients.
Artery junction points may become weak, causing ballooning of the blood
vessel wall that can form a small sac or aneurysm.
Cerebral aneurysms are common, but most are asymptomatic and are found
incidentally at autopsy.
Aneurysms can leak or rupture causing symptoms from severe headache to
stroke-like symptoms, or death.
The health care practitioner needs to maintain a high incidence of suspicion to make
the diagnosis, since many patients may have an initial small leak of blood
causing symptoms before a catastrophic bleed occurs.
Diagnosis of a brain aneurysm may require CT scans, lumbar puncture, or angiography.
Treatment to repair the aneurysm may involve neurosurgery to put a clip
across the weak blood vessel wall or clipping by interventional radiology.
What is a brain aneurysm and what causes a brain aneurysm?
The Circle of Willis is the junction of the four many arteries that supply the brain with nutrition (oxygen and glucose), two carotid arteries and two vertebral arteries. This loop of arteries is located at the base of the brain and sends out smaller branch arteries to all parts of the brain. The junctions where these arteries come together may develop weak spots. These weak spots can balloon out and fill with blood, creating the outpouchings of blood vessels known as aneurysms. These sac-like areas may leak or rupture, spilling blood into surrounding tissues.
Aneurysms have a variety of causes including
high blood pressure and atherosclerosis,
trauma, heredity, and abnormal blood flow at the junction where arteries come together.
There are other rare causes of aneurysms. Mycotic aneurysms are caused by
infections of the artery wall. Tumors and trauma can also cause aneurysms to
form. Drug abuse, especially cocaine, can cause the artery walls to inflame and
Brain aneurysms (aneurysms within arteries in the brain) are a common
occurrence. At autopsy,
incidental asymptomatic aneurysms are found in more than 1% of people. Most
aneurysms remain small and never become an issue or are diagnosed. Some,
however, may gradually become larger and exert pressure on surrounding brain tissue
and nerves and may be diagnosed because of symptoms such as:
The greater concern is a brain aneurysm that leaks or ruptures,
and potentially causes stroke or death. Bleeding leaks into one of the membranes
that covers the brain and spinal canal and is known as a subarachnoid hemorrhage
(sub= beneath + arachnoid=one of the brain coverings + hemorrhage=bleeding).
Medical Author: Melissa Conrad Stöppler, MD
Medical Editor: Dennis Lee, MD
What are some common types of aneurysms?
The most common types of
aneurysms involve the aorta, the large vessel that carries oxygen-containing
blood away from the heart. In particular, aneurysms most commonly develop in the
abdominal portion of the aorta and are designated abdominal aortic aneurysms. Abdominal aortic aneurysms are most common in men
over the age of 60. Most aortic aneurysms are caused by atherosclerosis
("hardening of the arteries") since this condition can weaken the walls of the
aorta and lead to thinning and widening of the affected areas.
Another type of aneurysm is a
brain aneurysm. Brain aneurysms are widened areas of arteries or veins
within the brain itself. These may be caused by head injury, an inherited (congenital) malformation of the vessels, high blood
pressure, or atherosclerosis. A special type of brain aneurysm is known as a
berry aneurysm. Berry aneurysms are small, berry-shaped outpouchings of the main
arteries that supply the brain and are particularly dangerous since they are
susceptible to rupture, leading to often fatal bleeding within the brain. Brain
aneurysms can occur at any age but are more common in adults.