Early Warning Signs of a Brain Aneurysm

A brain aneurysm is a bulge or dilation in an artery in the brain. Aneurysms occur in areas where the walls of the artery are thin or weak. Aneurysms develop in approximately one in 20 people, according to the Merck Manual. The National Institutes of Health, or NIH, notes that small brain aneurysms often cause no symptoms 1. Early warning signs of a brain aneurysm may appear when it grows large enough to press on nerves or if it leaks blood into the brain or bursts.

Is This an Emergency?

If you are experiencing serious medical symptoms, seek emergency treatment immediately.

Eye or Vision Problems

Cedars-Sinai Medical Center notes that a drooping eyelid or complaints of double vision are possible warning signs of a brain aneurysm pressing against a nerve or beginning to leak blood. A person may mention feeling pain behind or above one eye, or an observer may notice dilation of their pupils. Other early warning signs of a brain aneurysm include blurred vision and photophobia or light sensitivity, notes the Brain Aneurysm Foundation. These signs may precede a rupture by minutes or even weeks.


A minority of people with aneurysms may experience headaches in the days or weeks preceding the rupture of a brain aneurysm. The National Institute of Neurological Disorders and Stroke, or NINDS, mentions that a leaking aneurysm may cause these warning headaches, or sentinel headaches 1. When an aneurysm bursts, the person may experience what some have described as the worst headache of their life. Complaints about sudden, intense headaches may be early warning signs of a hemorrhaging brain aneurysm. A burst aneurysm is fatal in approximately half of all cases, warns MayoClinic.com. A person who complains of a sudden excruciating headache, either by itself or in conjunction with other symptoms, requires immediate medical attention. The Merck Manual notes that elderly persons may experience only mild headache or no headache.

Nausea and Loss of Consciousness

Early warning signs of a growing or leaking brain aneurysm include nausea, vomiting and stiff neck, notes the NINDS. A person may lose consciousness for a brief period in the minutes or weeks before a brain aneurysm ruptures, warns Cedars-Sinai. Often she will appear sleepy and confused when she wakes up and she may fall into this state of confusion again in a few minutes or hours. Sometimes a person lapses into a coma or he may experience a seizure. In these cases the person requires immediate medical attention.

Weakness or Paralysis

A ruptured brain aneurysm may cause weakness, numbness or paralysis on one side of a person's face, notes the NIH. Cedars-Sinai adds that the paralysis may be on one side of the body. An observer may also notice that the afflicted person's breathing pattern changes frequently.