What is a brain aneurysm?
A brain aneurysm is a bulge or ballooning area of a part of a blood vessel in the brain. It is most often seen in arteries (the vessels that pump oxygen-rich blood from the heart) rather than veins (the vessels that carry low-oxygen blood and waste products back to the heart).
Normally, blood circulates through the body from the heart through arteries, then into capillaries, then to veins, returning to the heart. Arteries have thick walls and carry blood that is under high pressure. Blood carried in arteries is rich with oxygen and nutrients as it is being pumped from the heart. Big arteries gradually get smaller. These then lead into the capillaries, which are small blood vessels where the exchange of oxygen, nutrients and waste happens. Blood flow slows down as it heads into the capillaries. Blood then enters the veins. Veins have thin walls and carry blood that is under low pressure, where the oxygen and nutrients have been used and waste products from tissues are returning to the heart to be replenished.
With a brain aneurysm, there is a thinning of the artery wall, and a bulge/pouch develops at the weak spot. If the aneurysms bursts, it causes bleeding in the brain. This can be life-threatening.
Signs and symptoms of a brain aneurysm
Most brain aneurysms do not cause any symptoms if they have not burst. Sometimes—if the aneurysm is large—it may press on tissue or nerves and cause pain, or it may cause a dilated pupil or vision changes.
The key symptom for a burst aneurysm is a sudden, severe headache. This is often described as a thunderclap or the “worst headache of your life”.
Other symptoms in addition to the headache may include:
- Neck stiffness
- Nausea and vomiting
- Vision changes: seeing double, blurry vision, bothered by lights
- Drooping eye lid(s)
- Dilated pupil(s) (enlarging of the black centre of the eye)
- Weakness, numbness or loss of movement in an arm, leg or one side of the body
- Problems with speaking
- Confusion
- Sudden collapse
What are the causes of aneurysms?
Some people may be more likely to develop a brain aneurysm. This is due to an abnormal development in their artery walls from birth. Some aneurysms can be a result of other conditions that increase the risk of developing a brain aneurysm:
- Vascular Ehlers-Danlos syndrome, Marfan syndrome and Loeys-Dietz syndrome—genetic conditions that affect connective tissues
- Sickle cell disease—an inherited blood disorder
- Polycystic kidney disease—an inherited disorder that causes cysts to form in the kidneys
- Arteriovenous malformations (AVMs)—a complex tangle of abnormal blood vessels
Having a first-degree relative, like a parent or biological sibling, with a brain aneurysm also increases the risk.
Other known risk factors for developing aneurysms in adulthood include smoking, high blood pressure, substance use and excessive alcohol use.
Aneurysms in children are rare and account for less than 5% of all brain aneurysms. Brain aneurysms in children are usually more complex, large and present differently than those in adults.
Diagnostic imaging and genetic testing
Diagnostic imaging is important in identifying an aneurysm. There are different types of imaging that can be performed to diagnose an aneurysm:
- Computed tomography (CT) scan: A CT scan uses X-rays and a computer to take “slice-like” pictures of the brain. Sometimes, further special CT imaging is done with contrast dye to take further pictures of the vessels of the brain. This is called a CT–Angiogram.
- Magnetic resonance imaging (MRI): An MRI uses a strong magnet to take a picture of the brain. The images of the arteries in the brain are called MRI–Angiograms (MRAs). Sometimes, further special MRI imaging is done with contrast dye to take further pictures of the vessels of the brain.
- Cerebral angiogram: A cerebral angiogram uses medical imaging and contrast dye to create a map of the arteries so they can be seen by X-rays. It is the gold standard test for understanding all the unique details of an aneurysm and blood flow.
Given that genetics and inherited conditions may also play a role in the development of an aneurysm, your child’s health-care team may also discuss whether genetic testing is appropriate.
Medications
Medications may be used to treat some symptoms caused by aneurysms, such as headaches or seizures. However, there are currently no medications to treat aneurysms directly.
Treatment
The main treatment options for brain aneurysms include open brain surgery (craniotomy and clipping) and endovascular surgery (endovascular embolization and endovascular flow diversion). Some aneurysms may require a combination of treatments.
Your child will be assessed by a group of neurovascular specialists including neurosurgeons, interventional neuroradiologists, and stroke neurologists. Your child’s treatment recommendations will be made based on their age, health status, and the size and location of the brain aneurysm.
Open surgery (craniotomy and aneurysm clipping)
Your child’s neurosurgeon will make an incision on the scalp and remove part of the skull bone temporarily to access the aneurysm. With special equipment, the aneurysm is located and clipped to separate it from the normal arteries. The skull bone is then re-attached, and the incision is closed.
If your child’s aneurysm has burst, the goal of this surgery is to remove the blood clot. The aneurysm may also need to be treated/removed urgently to prevent further bleeding. Your child will need time to recover from the bleed, including a period of rehabilitation therapy.
Endovascular surgery
- Embolization – Your child’s interventional neuroradiologist will insert a catheter into an artery in your child’s leg, wrist, or back of the hand, which is threaded through the blood vessels to the brain. Once the aneurysm is located, an embolizing agent (either coils or glue) is injected to block it and prevent blood flow into the aneurysm.
- Flow diversion – Your child’s interventional neuroradiologist will insert a catheter into an artery in your child’s leg, wrist, or back of the hand, which is threaded through the blood vessels to the brain. Once the aneurysm is located, a cylindrical tube (flow diverting stent) is placed into the blood vessel where the aneurysm has formed. This tube promotes blood flow through the blood vessel instead of into the aneurysm.
How to prevent aneurysm complications
With a diagnosis of an aneurysm, it is important to strive for good vascular health with a healthy diet, exercise and maintaining a healthy weight. Smoking, substance use and excessive alcohol use should be avoided.
Routine screening and follow-up can help detect aneurysms and prevent complications for those with conditions that increase the risk of developing a brain aneurysm.
Complications of a burst aneurysm
Brain injury from a burst brain aneurysm may be life-threatening or cause significant disability. An urgent open brain surgery may be needed depending on the location of the bleeding, the amount of blood and the amount of pressure the brain is under. The goal of this surgery is to remove the blood clot from the burst aneurysm. The aneurysm may also need to be treated/removed urgently to prevent further bleeding. Your child will need time to recover from the bleed, including a period of rehabilitation therapy.
Vasospasm, a narrowing of the blood vessels caused by the bleeding in the brain, is also a complication that can happen with a burst aneurysm. It usually develops about five to eight days after bleeding. Vasospasm can damage areas of the brain due to the resulting decrease in blood supply. Treatment for vasospasm includes medication and hydration (drinking water or receiving intravenous [IV] fluids) but might require other invasive treatments.
Helping your child
Receiving the diagnosis of an aneurysm can be very stressful and emotional. Your child’s health-care team can suggest resources that may be available for you and/or your child to help to with coping.
For more information on coping, see:
- Living with a chronic condition: Overview
- Living with a chronic condition: Helping your child manage their health
- Living with a chronic condition: Maintaining your child's everyday routines
- Living with a chronic condition: Supporting yourself as a caregiver
- Mental health learning hub
- Guided audio meditations
- Mental health animations for kids and teens
For more information on seizures, see:
Follow-up care
Your child will require several years of follow-up care and imaging to ensure that the aneurysm has been treated and there is no evidence of it coming back.
When to seek medical attention
A burst aneurysm can be life threatening. It is important to take your child to the nearest Emergency Department if they experience any of the following symptoms:
- Sudden severe headache
- Neck stiffness
- Nausea and vomiting
- Vision changes: seeing double, blurry vision, bothered by lights
- Drooping eye lid(s)
- Dilated pupil(s) (enlarging of the black centre of the eye)
- Weakness, numbness or loss of movement in an arm, leg or one side of body
- Problems with speaking
- Confusion
- Sudden collapse
At SickKids
SickKids Neurosurgery Clinic – SickKids Neurosurgery offers the highest level of care to children with all types of neurosurgical disorders.
Paediatric Neurovascular Program – The Paediatric Neurovascular Program is made up of a team of specialists dedicated to providing care to children with neurovascular diseases.
References
Hetts SW, Narvid J, Sanai N, Lawton MT, Gupta N, Fullerton HJ, Dowd CF, Higashida RT, Halbach VV. Intracranial aneurysms in childhood: 27-year single-institution experience. American Journal of Neuroradiology. 2009 Aug;30(7):1315-24. doi: 10.3174/ajnr.A1587.
Bisson DA, Dirks P, Amirabadi A, Shroff MM, Krings T, Pereira VM, Muthusami P. Unruptured intracranial aneurysms in children: 18 years' experience in a tertiary care pediatric institution. J Neurosurg Pediatr. 2019 May 24;24(2):184-189.