Brain Aneurysm

Cerebral Aneurysm

Normal

Abnormal

The brain has many arterial blood vessels that supply blood pumped by the heart. When the wall of a blood vessel becomes weak and/or thin, it forms a bulge or a bubble. This bulge or bubble is called an aneurysm.

An aneurysm may press on areas of the brain and cause various symptoms (below). Aneurysms may also rupture, causing bleeding in the brain. This bleeding results in Subarachnoid Hemorrhage (bleeding into the subarachnoid space of the brain).

Often asymptomatic

Focal neurological deficits depending on location; for example, if the aneurysm compresses the area of brain controlling the left leg, then left leg weakness will occur.

Mild headaches

Nausea

Neck stiffness

Severe "thunderclap" headaches if the aneurysm ruptures (Subarachnoid Hemorrhage)

Genetic predisposition in persons with Polycystic Kidney Disease or coarctation of the aorta

Cause often unknown

Examination:

Focal neurological deficits (explained above)
Neck stiffness if aneurysm has ruptured

Imaging:

Cerebral Angiography (dye is injected into the carotid artery to get an image of the blood vessels of the brain)
CT scan will usually show bleeding after an aneurysmal rupture
MRI

Laboratories:

- Lumbar puncture (spinal tap) -- cerebrospinal fluid will show blood after an interval of time if there is aneurysm rupture.

Electrocardiogram: may cause EKG abnormalities

Subarachnoid Hemorrhage may cause heart abnormalities

Unruptured aneurysms:

Large Aneurysms are surgically clipped at their bases to prevent rupture.
Small (less than 1/2 centimeter) ones without symptoms are usually followed with repeated cerebral angiographies.