What are the symptoms of a brain aneurysm?

In this video, learn about the key signs and symptoms of brain aneurysms from Kenneth Blumenfeld, MD, with Good Samaritan Hospital.
Piedmont Heart Institute
Most cerebral aneurysms do not show symptoms until they either become very large or burst. Small, unchanging aneurysms, generally will not produce symptoms, whereas a larger aneurysm may press on tissues and nerves. Symptoms may include pain above and behind the eye; numbness, weakness, or paralysis on one side of the face; dilated pupils; and vision changes. When an aneurysm hemorrhages, an individual may experience a sudden and extremely severe headache, double vision, nausea, vomiting, stiff neck, and/or loss of consciousness. Individuals usually describe the headache as "the worst headache of my life" and it is different in severity and intensity from other headaches that people may experience. "Sentinel" or warning headaches may result from an aneurysm that leaks for days or weeks prior to rupture. Only a minority of individuals have a sentinel headache prior to aneurysm rupture.
Dr. Mehmet Oz, MD
Cardiology (Cardiovascular Disease)
Watch this video to learn more from Dr. Mehmet Oz about symptoms of aneurysms.

There are generally no symptoms of cerebral aneurysm, until or unless they rupture. They then cause a severe headache that comes on immediately, as if one were being “shot in the head.” Ruptured aneurysms cause death in 50% of cases. Sometimes there are “low volume bleeds” with similar headaches that go away quickly, but they often precede a catastrophic bleed. This is why someone with the abrupt onset of a severe headache should always be evaluated immediately in an emergency room.

The sharpest symptom of a brain aneurysm is usually a sudden, severe headache. Other symptoms include: nausea and vomiting; stiff neck; blurred vision; sensitivity to light; seizure; loss of consciousness, and confusion.

An unruptured aneurysm may produce less severe symptoms, depending on its size. But a large unruptured aneurysm can lead to: pain around an eye; dilated pupil; change in vision; drooping eyelid; or numbness, weakness or paralysis on one side of the face.

Remember, a brain aneurysm always requires immediate medical attention.

A brain aneurysm is an emergency, so it's critical to know the signs. In this video, stroke neurologist Dr. Carolyn Brockington describes the symptoms that should make you reach out for immediate medical help.

Aneurysms are abnormal parts of blood vessels where the wall of the vessel becomes weak and the vessel balloons outward. Most brain aneurysms do not cause any symptoms, unless they burst and cause subarachnoid hemorrhage, which causes sudden and severe headache and may cause confusion, sleepiness, and other neurological signs such as weakness. In some cases, unruptured aneurysms may cause symptoms, due to pressure of the aneurysm on surrounding nerves or brain tissue. Symptoms may include headache, loss of vision, abnormalities in eye movements, weakness, and facial pain. 

Johns Hopkins Medicine

Brain aneurysms may be asymptomatic (no symptoms) or symptomatic (with symptoms). Symptoms associated with brain aneurysms depend on the location of the aneurysm in the brain.

  • sudden severe headache
  • nausea,
  • vomiting
  • visual disturbance
  • loss of consciousness
  • facial pain
  • numbness
  • weakness
  • paralysis
  • double vision
  • seizure

Although a cerebral aneurysm may be present without symptoms, the most common initial symptom of a cerebral aneurysm is a subarachnoid hemorrhage (SAH). SAH is bleeding into the subarachnoid space (the space between the brain and the membranes that cover the brain). A ruptured cerebral aneurysm is the most common cause of SAH. SAH is a medical emergency and may be the cause of a hemorrhagic (bleeding) stroke. The symptoms of an aneurysm may resemble other problems or medical conditions. Always consult your physician for a diagnosis.

Brain aneurysms most frequently present for medical attention because they bleed, causing vague, non-specific symptoms such as headaches, visual problems, slowed mental processes, balance problems, etc. The majority of aneurysms that rupture do so without any preliminary signs or symptoms. Some effects that occur upon rupture are:
  • Onset of a "thunderclap" (sudden, extremely painful) headache
  • Stiff neck
  • Intolerance of bright light
  • Nausea and/or vomiting
  • Seizures
  • Sudden weakness
  • Loss of consciousness

If you experience a sudden and severe headache, seek immediate medical attention, as it possibly may signal SAH as the cause.

In about 20 percent of aneurysms that go on to rupture, a "warning leak" occurs several days before subarachnoid hemorrhage. In these patients, the warning headache may be much milder than the thunderclap. Small strokes or seizures also may occur.

Unruptured aneurysms can press on adjacent brain structures such as cranial nerves and cause symptoms such as cranial nerve palsy, dilated pupils, double vision and pain above and behind the eye.

Brain aneurysms usually won't show signs or symptoms before they hemorrhage. Sometimes, though, an aneurysm may press on surround brain structures, causing headache, numbness, pain behind the eye, vision change, and weakness. Doctors can determine if these symptoms and warning signs are related to a cerebral aneurysm, often by using imaging tests such as computed tomography (CT) and magnetic resonance imaging (MRI) scans. Brain angiograms may also be used for treatment planning.

Symptoms vary depending on the nature of the aneurysm. Small aneurysms that do not grow or rupture typically produce no symptoms. Aneurysms that are growing may put pressure on brain tissue or surrounding nerves. This may result in pain behind or above the eyes, dilated pupils, a drooping eyelid, changes in vision, numbness, or even face paralysis. Once an aneurysm ruptures, the result is a very painful headache. The pain is sudden and severe. Nausea and vomiting may occur. The person may lose consciousness. Double vision, neck stiffness, light sensitivity, and confusion also are possible symptoms.

Continue Learning about Brain Aneurysms

Brain Aneurysms

The arteries in the brain occasionally develop a weak spot or bulge, which is called an aneurysm. The concern is that it can burst or rupture at that weak spot, causing blood to leak into the brain, a brain aneurysm hemorrhage. A ...

rupture is very serious, often fatal or leaving permanent paralysis and disability. Doctors detect aneurysms with various scans. There are two surgical treatments that reduce the risk of rupture. One is open brain surgery (craniotomy) the other, less invasive, is endovascular surgery. Which is appropriate depends on where the aneurysm is located. An aneurysm is a very serious medical condition and requires immediate attention.

Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.