A brain aneurysm, also known as a cerebral or berry aneurysm, is an abnormal widening of part of an artery in the brain caused by a weakness in the artery wall. The force of blood against the wall of the weakened blood vessel results in a bulging, blood-filled, balloon-like swelling. Brain aneurysms can leak or rupture.
Causes of Brain Aneurysms
Brain aneurysms are more common in adults than children and slightly less common in men than women, but anyone at any age can develop a brain aneurysm. Some factors can place a person at greater risk of a brain aneurysm, such as:
- an abnormality in an artery wall present at birth
- a family history of brain aneurysms, especially in immediate relatives
- inherited polycystic kidney disease
- hereditary connective tissue disorders, such as Ehlers-Danlos syndrome
- cerebral arteriovenous malformation (AVM), a circulatory problem in the brain which disrupts blood flow
- head injury
- high blood pressure
- infection in an arterial wall
- tumours of the head and neck
- atherosclerosis (fatty buildup inside the artery walls)
- cigarette smoking
- excessive alcohol consumption
- drug abuse, particularly cocaine
- low post-menopausal oestrogen levels
Symptoms of Brain Aneurysms
Most cerebral aneurysms have no symptoms unless they grow large, leak blood or rupture. An unruptured, growing aneurysm which presses on nerves and brain tissue may cause pain behind and above an eye, vision changes, dilated pupils, a drooping eyelid, or numbness, weakness or paralysis on one side of the face.
A suspected ruptured aneuryism requires emergency medical attention. Symptoms of a ruptured aneurysm may include:
- a sudden, severe, intense headache worse than any headache previously experienced
- blurred or double vision
- a drooping eyelid
- sensitivity to light
- nausea and vomiting
- a stiff neck
- mental confusion
- seizure
- loss of consciousness
Ruptured Brain Aneurysm Complications
A ruptured brain aneurysm causes bleeding into the brain. The blood may damage nearby brain cells and is life-threatening. Pressure can build up inside the skull and interrupt the brain's supply of blood and oxygen. Complications may arise after an aneurysm has burst, including:
- re-bleeding: The aneurysm may burst again causing more damage to brain cells.
- subarachnoid hemorrhage (bleeding between the skull and brain)
- hydrocephalus: Cerebrospinal fluid accumulates in the skull, which increases pressure on the brain and may damage tissues.
- hyponatremia (decreased blood sodium levels which may cause brain cell swelling and damage)
- vasospasm: Blood vessels in the brain contract and restrict blood flow to the brain, which may cause a stroke.
According to the National Institute of Neurological Disorders and Stroke, a ruptured aneurysm occurs in approximately 10 in every 100,000 people annually in the United States, usually aged between 30 and 60 years. The risk of rupture may increase with alcohol and drug abuse, smoking and hypertension.
Most brain aneurysms have no symptoms and never rupture, but approximately half of all ruptured brain aneurysms are fatal. People who are worried they may be at risk of a brain aneurysm or think they have symptoms should seek medical advice to discuss the appropriateness of a diagnostic test.
Sources:
Mayo Clinic. "Brain Aneurysm" (Accessed 2nd February 2011).
National Heart Lung and Blood Institute. "Aneurysm" (Accessed 2nd February 2011)
National Institute of Neurological Disorders and Stroke. "Cerebral Aneurysm Fact Sheet" (Accessed 2nd February 2011).
Sharon Kirby - Sharon is a freelance health writer and contributes to various print and online publications. Writing credits include Nursing Times, Good ...
