An aneurysm is a localized, abnormal bulging or ballooning in the wall of an artery, caused by a weakness in the vessel wall. This condition can occur in any artery in the body, though the most commonly discussed are those found in the brain and the aorta. Many people live with an aneurysm for decades without ever knowing it is present, as it often remains asymptomatic. The possibility of long-term survival hinges almost entirely on whether the aneurysm is detected and remains stable in an unruptured state. Modern medicine focuses on assessing the risk of rupture and managing the condition to allow individuals to maintain a healthy life.
The Critical Difference Between Ruptured and Unruptured Aneurysms
An unruptured aneurysm has not burst, and this is the state in which most people live with the condition, often unaware of its existence. These are typically monitored conservatively unless they present a high risk for rupture.
A ruptured aneurysm represents a medical emergency that carries a high rate of mortality and morbidity. When the arterial wall bursts, it causes bleeding into the surrounding tissue, such as a subarachnoid hemorrhage in the brain. This event is acutely life-threatening and requires immediate, aggressive intervention. Therefore, living with an aneurysm refers almost exclusively to the scenario of an unruptured, stable lesion that is either being actively monitored or has been successfully treated to prevent rupture.
The goal of medical management is to maintain the unruptured state, as the consequences of rupture are severe. Many aneurysms never rupture throughout a person’s lifetime, especially smaller ones, which is why a conservative approach is frequently adopted.
How Aneurysms Are Diagnosed
Aneurysms are typically discovered incidentally during imaging for an unrelated condition or through a symptomatic presentation. Incidental discovery often occurs during scans, such as a computed tomography (CT) scan or magnetic resonance imaging (MRI), ordered for symptoms like persistent headaches or dizziness. This pathway frequently identifies smaller, asymptomatic aneurysms.
When an aneurysm is suspected, specialized imaging techniques are used for definitive diagnosis. A CT angiography (CTA) or magnetic resonance angiography (MRA) involves injecting a contrast dye to create detailed, three-dimensional images of the blood vessels. These non-invasive tests clearly show the aneurysm’s size, shape, and exact location.
Cerebral angiography, a more invasive procedure, is sometimes performed to provide the most precise images of blood flow and structure. This involves threading a catheter through a blood vessel, often in the groin, up to the arteries in the brain where a dye is then injected. In the event of a rupture, a sudden, severe “thunderclap” headache, often described as the “worst headache of my life,” is the hallmark symptom and immediately prompts emergency diagnostic imaging.
Determining Long-Term Prognosis
The long-term prognosis for someone living with an unruptured aneurysm is determined by a careful assessment of its rupture risk versus the risks associated with intervention. Aneurysm size is a primary concern, as larger aneurysms generally have a higher chance of rupturing due to increased wall tension. While there is no universal cutoff, aneurysms greater than 7 millimeters in diameter are often viewed with greater concern, although smaller ones can still rupture.
The shape of the aneurysm is another significant factor, with irregular contours, such as a “daughter sac” or a non-spherical shape, indicating potential instability and a higher risk of rupture. Certain locations within the brain are also inherently riskier, such as those in the posterior circulation or the anterior communicating artery, due to higher hemodynamic stress.
Patient health and lifestyle choices also influence the rupture risk profile. Uncontrolled hypertension places continuous, excessive strain on the weakened arterial wall, making blood pressure management a major focus of care. A history of smoking is strongly associated with aneurysm growth and rupture, and family history of aneurysms or hemorrhagic stroke can also indicate an elevated genetic predisposition.
Management and Intervention Options
Once an unruptured aneurysm is diagnosed and its risk profile is established, management follows one of two main paths: watchful waiting or active intervention. Watchful waiting is the conservative approach recommended for low-risk aneurysms that are small, regularly shaped, and asymptomatic. This strategy involves active surveillance through regular follow-up imaging, such as annual MRA or CTA scans, to monitor for any changes in size or shape.
For individuals under watchful waiting, lifestyle modifications are a core component of long-term management. These changes focus on reducing strain on the arterial walls, which includes stringent control of blood pressure, cessation of all tobacco use, and moderation of caffeine intake.
For high-risk aneurysms, or those that show signs of growth during monitoring, active intervention is pursued to prevent rupture. There are two primary categories of treatment. Endovascular procedures are minimally invasive, involving the insertion of a catheter to the aneurysm site, where materials like platinum coils (coiling) or a mesh tube (flow diversion) are deployed to block blood flow into the bulging sac.
The alternative is surgical clipping, an open neurosurgical procedure where a small metal clip is placed at the base of the aneurysm to isolate it from the main artery. Both interventions aim to eliminate the risk of rupture. The choice between these options depends on the aneurysm’s specific anatomy, its location, and the patient’s overall medical profile.