Brain Aneurysms

What is a brain aneurysm?

An aneurysm is a bulge in the wall of a blood vessel caused by a small area of weakness. Aneurysms can occur in various parts of the body, but one of the most common locations is the brain. These are known as intracranial or cerebral aneurysms. Some aneurysms have the potential to rupture, which can result in bleeding around the brain called subarachnoid haemorrhage.

Brain aneurysms most commonly affect middle-aged and older adults with a higher prevalence in women. They are extremely rare in children. The cause is usually unknown, although some individuals have a genetic predisposition to developing them.

How common are brain aneurysms?

Brain aneurysms are present in approximately 3% of the population (3 in 100 people). Several factors increase the risk of developing a brain aneurysm:

• Family history of brain aneurysm or subarachnoid haemorrhage
• Atherosclerosis — build-up of plaque in the arteries
• Smoking — damages blood vessel walls
• High blood pressure — increases pressure on vessel walls
• Female sex
• Increasing age
• Polycystic Kidney Disease (ADPKD)
• Sickle cell disease

Are brain aneurysms dangerous?

Many aneurysms are benign, causing no symptoms and never rupturing. However, some do rupture, leading to life-threatening bleeding around the brain known as subarachnoid haemorrhage. Rarely, unruptured aneurysms cause symptoms such as impaired vision, seizures, or strokes due to pressure on nearby brain structures.

Factors known to increase the risk of rupture include:

• Aneurysm size — larger aneurysms carry higher risk
• Location — posterior circulation aneurysms are more prone to rupture
• Growth over time — increasing size on follow-up imaging
• Previous rupture — risk of further rupture is elevated
• Family history of subarachnoid haemorrhage
• Smoking and hypertension
• Irregular aneurysm shape

Treatment options

Not all aneurysms require immediate treatment. The decision depends on size, shape, location, symptoms, and patient factors. Options include:

• Observation and surveillance — for small, low-risk unruptured aneurysms with regular imaging follow-up
• Endovascular coiling — minimally invasive treatment in which platinum coils are inserted into the aneurysm via a catheter to induce thrombosis
• Flow diversion — devices such as the Pipeline Embolization Device redirect blood flow away from the aneurysm
• Intrasaccular devices — devices deployed inside the aneurysm to disrupt flow
• Surgical clipping — open neurosurgical approach for selected cases

What to expect

At your consultation, we will review your symptoms, medical history, and any imaging. We will discuss the available treatment options and agree a personalised plan. You are welcome to bring a family member. Questions are always encouraged.

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