Silent Aneurysms: Why Some Brain Conditions Go Unnoticed
A brain aneurysm is a weakened area in a brain artery that bulges outward
. Many aneurysms cause no symptoms at all, so a person can have one for
years without knowing it.
Why can an aneurysm be “silent”?
- It may be small. Small aneurysms often don’t press on nearby nerves or brain tissue.
- It may not affect blood flow. If circulation remains normal, there may be no noticeable neurological symptoms.
- The brain itself doesn’t sense pain. Symptoms generally occur when an aneurysm affects surrounding structures or leaks/ruptures.
- It may be discovered accidentally. An aneurysm can show up during a CT or MRI performed for an unrelated reason.
When symptoms can occur
A larger or expanding aneurysm may sometimes cause headaches, pain around the eye, vision changes, a drooping eyelid, or problems with eye movement. However, these symptoms aren’t specific to aneurysms and can have many other causes.
The major danger is rupture, which can cause bleeding around the brain (subarachnoid hemorrhage). A sudden, extremely severe headache—often described as a “thunderclap headache”—is a medical emergency, particularly if accompanied by vomiting, neck stiffness, confusion, fainting, seizures, weakness, or difficulty speaking.
If such symptoms occur suddenly, seek emergency medical care immediately rather than waiting to see whether they improve.
Not every unruptured aneurysm needs treatment. Doctors generally consider factors such as its size, location, shape, growth, previous rupture, and the person’s overall risk when deciding between monitoring and treatment.
