Brain Aneurysm
Brain Aneurysm: At a Glance
What it is: A brain aneurysm is a bulge in a blood vessel in the brain caused by a weak spot in the vessel wall.
How it affects people: Often causes no symptoms, but in some cases may rupture, leading to a sudden headache, severe illness or very occasionally press on nerves.
Key concern: Rupture, which can result in life-threatening bleeding around the brain (subarachnoid haemorrhage).
Diagnosis: Usually identified through brain imaging such as CT scan, MRI scans, or cerebral angiography.
Treatment options: Monitoring, endovascular procedures, or surgery depending on risk and size.
Outlook: Many aneurysms remain stable and never rupture. With expert care from a neurosurgeon, those that need treatment can often be managed safely and effectively.
What is a Brain Aneurysm?
A brain aneurysm occurs when a weak area in the wall of a blood vessel in the brain balloons out, creating a bulge. While many aneurysms remain small and low-risk, others may grow, press on nearby nerves, or rupture, causing bleeding around the brain and spinal cord.
Although the thought of an aneurysm can be frightening, not all require urgent treatment. Many can be safely monitored, and if intervention is needed, modern neurosurgery techniques mean outcomes are far more positive than in the past.
Types of Brain Aneurysms
There are several types of brain aneurysms:
Saccular aneurysm (berry aneurysm): The most common form, shaped like a berry on a stem.
Fusiform aneurysm: A broad swelling that affects the entire circumference of the artery.
Mycotic aneurysm: Rare, caused by infection in the artery wall.
Specialists may also classify aneurysms according to their location within specific areas of the brain.
Brain Aneurysm Symptoms
Common signs of a brain aneurysm (unruptured aneurysm)
Most unruptured aneurysms cause no symptoms and are discovered incidentally on scans done for other reasons. When symptoms do occur, they may include:
Blurred or double vision
Eye pain
Dilated pupil
Headache
Emergency / red flag symptoms of a brain aneurysm (ruptured)
Sudden, severe headache often described as the “worst headache of your life”
Nausea and vomiting
Stiff neck
Sensitivity to light
Seizures
Loss of consciousness
Sudden difficulty speaking or weakness on one side of the body
Call 999 immediately if you experience these symptoms.
Causes and Who Is at Risk
Brain aneurysms develop when an artery wall becomes thin or weak. Most cases occur sporadically, without any single identifiable cause. However, certain lifestyle, health, and inherited factors may increase the likelihood of developing an aneurysm.
Brain aneurysms develop when an artery wall becomes thin or weak. Several factors can contribute to this, including:
Age-related changes in blood vessels
High blood pressure
Hardening of the arteries (atherosclerosis)
Head injury (rare)
Infections (rare)
Health and Family Factors You Can’t Change
Family history of cerebral aneurysms
Age
Sex
Inherited connective tissue disorders such as:
Polycystic kidney disease (ADPKD)
Ehlers–Danlos syndrome (type IV)
Marfan syndrome
Loeys–Dietz syndrome
Having a risk factor does not mean you will definitely develop a brain aneurysm.
Reducing Your Risk
You cannot always prevent a brain aneurysm from bleeding, but you can reduce your risk by:
Stopping smoking
Managing high blood pressure
Limiting alcohol consumption
Eating healthily and exercising regularly
Having check-ups if there is a family history of aneurysms
Getting a Diagnosis
A brain aneurysm is usually identified through specialist imaging tests
CT and CTA scan: Often the first tests, useful for detecting bleeding from a ruptured brain aneurysm.
MRI and MRA: Provide high-resolution images of the brain and its blood vessels without radiation.
Cerebral angiogram: The most detailed way to map blood vessels, but it is invasive and usually reserved for when precise information is essential.
These tests are highly accurate and help guide the safest treatment plan by a brain specialist or neurosurgeon.
Treatment Options for Brain Aneurysms
Brain aneurysm treatment depends on the size, type, location of the aneurysm, and the patient’s overall health. Options include:
Medical Management
Controlling risk factors such as high blood pressure, and support for lifestyle changes such as smoking cessation.
Ongoing Monitoring
Regular scans may be recommended if the aneurysm is small and low-risk.
Endovascular Procedures
Techniques such as an endovascular coil or stent placement repair the aneurysm from inside the blood vessel without open surgery.
Surgical Clipping
Open cranial surgery that closes off the aneurysm with small titanium clips.
Every patient’s case is carefully reviewed in collaboration with a radiologist and a wider multidisciplinary team. This ensures all treatment options are considered and the safest, most effective plan is chosen.
These procedures are highly specialised and should be carried out by an experienced consultant. Mr Kailaya-Vasan, consultant neurosurgeon, specialises in neurovascular surgery and minimal access cranial surgery, providing expert care for patients all across London, the United Kingdom and abroad.
Living with a Brain Aneurysm
Many aneurysms never rupture and can be monitored safely. If treatment is needed, surgical clipping or endovascular approaches mean most patients recover well and return to normal life.
With early diagnosis and the right specialist care, many patients recover well and return to normal activities. Under the care of a consultant neurosurgeon like Mr Kailaya-Vasan, treatment is planned carefully around each patient’s needs, with a strong focus on safety, precision, and long-term outcomes.
Book a consultation with Mr Ahilan Kailaya-Vasan
Receive a clear diagnosis and a tailored treatment plan from a leading consultant neurosurgeon. Appointments are available at top London hospitals, with remote options for international patients.
Seeking a second opinion?
If you have already received a diagnosis elsewhere, Mr Kailaya-Vasan can provide an independent review of your scans and medical notes, and explain the safest and most effective next steps.
FAQs about Brain Aneurysms
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Not all brain aneurysms are dangerous. Many remain small and stable. However, a ruptured aneurysm is a serious emergency that requires urgent specialist care.
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No. Many small aneurysms are monitored with regular scans. Surgery or endovascular treatment is only recommended if there is a higher risk of rupture.
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Call 999 immediately if you experience a sudden, severe headache (often described as the worst of your life), loss of consciousness, or sudden neurological symptoms like weakness or difficulty speaking.
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Recovery varies depending on whether the aneurysm has ruptured and the type of treatment performed. Patients treated for unruptured aneurysms often return to normal activities within weeks. Recovery from a ruptured aneurysm can take longer, but with close follow-up, many people regain independence.
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Not completely, but lifestyle changes such as quitting smoking and controlling blood pressure can lower your risk.
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The outlook depends on whether the aneurysm ruptures. Most unruptured aneurysms never cause harm and can be safely monitored or treated. If an aneurysm ruptures, it is a life-threatening emergency and around a third of patients do not survive, but outcomes are much better with rapid diagnosis and treatment from an experienced neurosurgeon.
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It is rare for a brain bleed to go completely unnoticed. Most bleeds on the brain cause sudden and often severe symptoms. If you ever develop a sudden, severe headache or neurological symptoms, seek emergency help immediately.
If you have any further questions, please get in touch.