Brain Aneurysm

Symptoms of a Brain Aneurysm

Most small, unruptured brain aneurysms cause no symptoms. When an unruptured aneurysm becomes large enough to press on nearby nerves or brain tissue, symptoms can include pain above or behind the eye, a dilated pupil, double vision or other vision changes, facial numbness or weakness, or other focal neurological symptoms depending on location.

A ruptured aneurysm typically presents very differently. The classic symptom is a sudden, severe headache that reaches maximum intensity quickly, often described as a thunderclap headache or the worst headache of a person’s life. Nausea, vomiting, neck stiffness, light sensitivity, seizure, confusion, weakness, or loss of consciousness may also occur.

Call 911 immediately for a sudden severe thunderclap headache or other symptoms of a possible ruptured aneurysm.

Risk Factors and Who May Need Screening

Brain aneurysms can occur in anyone, but certain factors are associated with aneurysm formation, growth, or rupture. Important modifiable factors include cigarette smoking and high blood pressure. Risk also varies with age, family history, aneurysm size and location, and certain inherited or vascular conditions.

Screening is not recommended for everyone. It may be considered for people with a strong family history — particularly two or more first-degree relatives with intracranial aneurysm or aneurysmal subarachnoid hemorrhage — and for selected patients with conditions associated with higher aneurysm risk. Screening is generally performed with CTA or MRA.

How Brain Aneurysms Are Diagnosed

Brain aneurysms are often discovered incidentally on imaging performed for another reason. CT angiography (CTA) and MR angiography (MRA) can show the aneurysm’s location, size, and overall shape. When more detailed vascular anatomy is needed, a cerebral angiogram, or digital subtraction angiography (DSA), provides high-resolution images and can help plan treatment.

At Atlantic Brain and Spine, evaluation may also incorporate advanced tools such as vessel-wall imaging and risk-assessment technologies when useful. The goal is not simply to confirm that an aneurysm exists, but to understand the features that influence rupture risk and determine whether observation or treatment is the safer path.

When Does a Brain Aneurysm Need Treatment?

Not every unruptured brain aneurysm needs treatment. Some can be safely monitored with follow-up imaging, while others are better treated to reduce the risk of rupture. The decision balances the aneurysm’s estimated rupture risk against the risks of intervention.

Size is only one part of that decision. Your neurovascular team also considers the aneurysm’s location and shape, whether it has grown over time, symptoms, age and overall health, smoking and blood pressure, and any personal or family history of aneurysm rupture. Documented growth can be particularly important, even when an aneurysm is relatively small.

For aneurysms being monitored, follow-up CTA or MRA is used to look for changes. When treatment is recommended, the aneurysm’s anatomy and the patient’s individual circumstances help determine the safest and most durable approach.

A ruptured aneurysm is different: it requires emergency treatment to secure the aneurysm, along with neurocritical care to manage the bleeding and potential complications.