An aneurysm is a weak area in the wall of a blood vessel that causes the blood vessel to bulge or balloon out. When an aneurysm occurs in a blood vessel of the brain, it is called a cerebral aneurysm.
Aneurysm - cerebral; Cerebral aneurysm
Causes, incidence, and risk factors
Aneurysms in the brain occur when there is a weakened area in the wall of a blood vessel. An aneurysm may be present from birth (congenital) or it may develop later in life, such as after a blood vessel is injured.
There are many different types of aneurysms. The most common type is called a berry aneurysm. This type can vary in size from a few millimeters to over a centimeter. Giant berry aneurysms can be bigger than 2 centimeters. These are more common in adults. Multiple berry aneurysms are passed down through families more often than other types of aneurysms.
Other types of cerebral aneurysm involve widening of an entire blood vessel, or they may appear as a "ballooning out" of part of a blood vessel. Such aneurysms can occur in any blood vessel that supplies the brain. Atherosclerosis, trauma, and infection, which can injure the blood vessel wall, can cause cerebral aneurysms.
About 5% of the population has some type of aneurysm in the brain, but only a small number of these aneurysms cause symptoms or rupture. Risk factors include a family history of cerebral aneurysms, and certain medical problems such as polycystic kidney disease, coarctation of the aorta, and endocarditis.
A person may have an aneurysm without having any symptoms. This kind of aneurysm may be found when an MRI or CT scan of the brain is done for another reason.
A cerebral aneurysm may begin to "leak" a small amount of blood. This may cause a severe headache that a patient may describe as "the worst headache of my life." It may be called a thunderclap or sentinel headache. This means the headache could be a warning sign of a rupture days or weeks after the headache first happens.
Symptoms may also occur if the aneurysm pushes on nearby structures in the brain or breaks open (ruptures) and causes bleeding into the brain.
Symptoms depend on the location of the aneurysm, whether it breaks open, and what part of the brain it is pushing on, but they may include:
Loss of vision
A sudden, severe headache is one symptom of an aneurysm that has ruptured. Other symptoms of an aneurysm rupture may include:
NOTE: A ruptured aneurysm is a medical emergency. Call your local emergency number, such as 911.
Signs and tests
An eye exam may show signs of increased pressure in the brain, including swelling of the optic nerve or bleeding into the retina of the eye. A brain and nervous system exam may show abnormal eye movement, speech, strength, or sensation.
The following tests may be used to diagnose cerebral aneurysm and determine the cause of bleeding in the brain:
Cerebral angiography or spiral CT scan angiography of the head to reveal the location and size of the aneurysm
Go to the emergency room or call the local emergency number (such as 911) if you have a sudden or severe headache, especially if you also have nausea, vomiting, seizures, or any other neurological symptoms.
Also call if you have a headache that is unusual for you, especially if it is severe or your worst headache ever.
There is no known way to prevent the formation of a berry aneurysm. Treating high blood pressure may reduce the chance that an existing aneurysm will rupture. Controlling risk factors for atherosclerosis may reduce the likelihood of some types of aneurysms.
If unruptured aneurysms are discovered in time, they can be treated before causing problems.
The decision to repair an unruptured cerebral aneurysm is based on the size and location of the aneurysm, and the patient's age and general health. The risks involved in both operating and watchful waiting must be carefully considered.
Bederson JB, Connolly ES Jr, Batjer HH, Dacey RG, Dion JE, Diringer MN, Duldner JE Jr, Harbaugh RE, Patel AB, Rosenwasser RH: American Heart Association Guidelines for the management of aneurysmal subarachnoid hemorrhage: a statement for healthcare professionals from a special writing group of the Stroke Council, American Heart Association. Stroke. 2009;40:994-1025.
Mack W, Dusick JR, Martin N, Gonzalez N. Principles of endovascular therapy. In: Daroff RB, Fenichel GM, Jankovic J, Mazziotta JC, eds. Bradley’s Neurology in Clinical Practice. 6th ed. Philadelphia, PA:Saunders Elsevier; 2012:chap 47.
Meyers PM, Schumacher HC, Higashida RT, et al: American HeartAssociation. Indications for the performance of intracranial endovascular neurointerventional procedures: a scientific statement from the American Heart Association Council on Cardiovascular Radiology and Intervention. Stroke Council, council on Cardiovascular Surgery and Anesthesia, Interdisciplinary Council on Peripheral Vascular Disease, and Interdisciplinary Council on Quality of Care and Outcomes Research. Circulation. 2009;119:2235-2249.
Luc Jasmin, MD, PhD, Department of Neurosurgery at Cedars-Sinai Medical Center, Los Angeles, and Department of Anatomy at UCSF, San Francisco, CA. Review provided by VeriMed Healthcare Network.Also reviewed by David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine; David Zieve, MD, MHA, Medical Director, A.D.A.M. Health Solutions, Ebix, Inc.