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.
Causes
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. A berry aneurysm can vary in
size from a few millimeters to over a centimeter. Giant berry aneurysms
can reach well over 2 centimeters. These are more common in adults.
Multiple berry aneurysms are inherited 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 high blood pressure.
Symptoms
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." Another phrase used to
describe this is a 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:
- Double vision
- Loss of vision
- Headaches
- Eye pain
- Neck pain
- Stiff neck
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. Seek immediate medical help.
Exams and Tests
An
eye exam may show evidence of increased pressure in the brain (raised
intracranial pressure), including swelling of the optic nerve or
bleeding into the retina of the eye. A brain and nervous system
(neurological) 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:
Treatment
Two common methods are used to repair an aneurysm:
- Clipping is the most common way to repair an aneurysm. This is done during open brain surgery. See also: Brain surgery (craniotomy)
- Endovascular repair, most often using a "coil" or coiling, is a less invasive way to treat some aneurysms.
If
an aneurysm in the brain ruptures, it is an emergency that needs
medical treatment and often requires surgery. Endovascular repair is
more often used when this happens.
Even if there are no symptoms, your doctor may order treatment to prevent a future, possibly fatal, rupture.
Not all aneurysms need to be treated right away. Those that are very small (less than 3 mm) are less likely to break open.
Your
doctor will help you decide whether it is safer to have surgery to
block off the aneurysm before it can break open (rupture).
Someone may be too ill to have surgery, or it may be too dangerous to treat the aneurysm because of its location.
Treatment may involve:
- Complete bedrest and activity restrictions
- Drugs to prevent seizures
- Medicines to control headaches and blood pressure
Once
the aneurysm is repaired, prevention of stroke from blood vessel spasm
may be necessary. This may include intravenous fluids, certain
medications, and letting the blood pressure get high.
Outlook (Prognosis)
The
outcome varies. Patients who are in deep comas after an aneurysm
rupture generally do not do as well as those with less severe symptoms.
Ruptured
cerebral aneurysms are often deadly. About 25% of people die within 1
day, and another 25% die within about 3 months. Of those who survive,
about 25% will have some sort of permanent disability.
Possible Complications
- Increased pressure inside the skull
- Loss of movement in one or more parts of the body
- Loss of sensation of any part of the face or body
- Seizures
- Stroke
- Subarachnoid hemorrhage
When to Contact a Medical Professional
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.
Prevention
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.
Alternative Names
Aneurysm - cerebral; Cerebral aneurysm
References
Bederson
JB, Connolly ES Jr, Batjer HH, Dacey RG, Dion JE, Diringer MN, Duldner
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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.
Meyers
PM, Schumacher HC, Higashida RT, Barnwell SL, Creager MA, Gupta R,
McDougall CG, Pandey DK, Sacks D, Wechsler JR: American Heart
Association. Indications for the performance of intracranial
endovascular neurointerventional procedures: a scientific statement from
the American Heart Associatino 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.
Patterson JT, Hanbali F, Franklin RL, Nauta HJW. Neurosurgery. In: Townsend CM, Beauchamp RD, Evers BM, Mattox KL, eds.
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