Brain aneurysms occur when a weak spot in a brain artery wall balloons out and can rupture, leading to bleeding in the brain. They develop from a combination of genetic predispositions, vascular risk factors, and sometimes external triggers. Below is a concise, evidence-based overview of common causes and contributing factors. Key causes and contributing factors
- Weak arterial walls and structural abnormalities: Some people are born with inherently weaker vessel walls or congenital artery-wall abnormalities, which can predispose to aneurysm formation.
- Hypertension (high blood pressure): Elevated pressure on artery walls accelerates wear and tear, increasing the risk of weakening and bulging.
- Smoking and tobacco use: Smoking damages blood vessels and accelerates atherosclerotic changes, markedly increasing rupture risk in people with aneurysms.
- Age and sex: The likelihood of aneurysm formation increases with age, and women have a somewhat higher risk of aneurysm rupture than men.
- Family history and genetic factors: A family history of brain aneurysms or certain genetic conditions (such as polycystic kidney disease, Ehlers-Danlos syndrome, and Marfan syndrome) raise risk.
- Other vascular conditions: Conditions that affect blood vessel integrity, like arteriovenous malformations (AVMs) or other connective tissue disorders, can contribute.
- Substance use: Cocaine and other illicit stimulants can acutely raise blood pressure and contribute to aneurysm formation or rupture.
- Head trauma and infections: Severe head injury or certain infections can precipitate aneurysm formation or rupture in some cases.
- Atherosclerosis and vessel wall changes: Accumulation of fatty deposits inside arteries (atherosclerosis) weakens walls and promotes aneurysm development.
- Polycystic kidney disease and other systemic diseases: Some systemic illnesses are associated with increased aneurysm risk.
Notes on rupture risk and presentation
- Most aneurysms are small and asymptomatic until rupture, which classically presents as a sudden, severe headache (“worst headache of my life”) with possible neck stiffness, nausea, or loss of consciousness.
- The risk of rupture increases with aneurysm size, location (some sites are more prone to rupture), and certain patient factors (age, hypertension, smoking, family history).
What reduces risk or helps with management
- Controlling blood pressure through lifestyle changes and medications.
- Smoking cessation and avoidance of tobacco products.
- Managing other vascular risk factors (healthy diet, regular exercise, weight management).
- Regular medical follow-up if an aneurysm is known or suspected, with imaging to monitor size and growth.
- In some cases, preventive treatment (such as surgical clipping or endovascular repair) is considered for larger or higher-risk aneurysms, based on individualized evaluation by specialists.
If you or someone you know has symptoms suggesting a brain aneurysm or a sudden severe headache, seek emergency medical care immediately. For personalized information, consider consulting a neurologist or neurosurgeon who can assess risk factors in the context of medical history and imaging results.
