Most aneurysms will cause no symptoms at all until they suddenly rupture, and some large aneurysms can cause symptoms that can be mistaken for other conditions. For example, an aneurysm may cause fatigue, behavioral changes, a decrease in focus or concentration, or trouble with balance or coordination. Other symptoms may include problems with peripheral vision, thinking or processing, speech, perception, or short-term memory. Since these symptoms can be caused by several conditions, they need to be investigated, usually with an imaging test, before an aneurysm can be diagnosed. (See Diagnosing and Treating an Aneurysm.)
If an aneurysm ruptures, or begins to leak in advance of a rupture, symptoms are sudden and sometimes severe. Many people experiencing the pain of a leaking or ruptured aneurysm have described it as a thunderclap, or “the worst headache of my life.” Symptoms of an imminent rupture or the internal bleeding that results from a rupture (a subarachnoid hemorrhage) also include:
Anyone experiencing these severe symptoms should be examined immediately and will likely have imaging tests done to determine the cause of the symptoms. If the scans reveal evidence of a subarachnoid hemorrhage caused by a cerebral aneurysm, or a leaking aneurysm in danger of a rupture, the patient will require immediate treatment to prevent a rupture or repair the damage.
Reviewed by: Jared Knopman, M.D.
Last reviewed/last updated: February 2021