10 Critical Brain Aneurysm Symptoms You Should Never Ignore

A brain aneurysm, also known as a cerebral aneurysm or aneurisma cerebral, is a potentially life-threatening condition characterized by a weakened, bulging area in the wall of a blood vessel in the brain. Understanding what is a brain aneurysm and recognizing its symptoms early can be crucial for survival and preventing serious complications.

Many people wonder “what does a brain aneurysm feel like?” The truth is that most unruptured brain aneurysms cause no symptoms at all and may go undetected for years. However, when symptoms do occur—either from an unruptured aneurysm pressing on brain tissue or from a ruptured aneurysm—they can be severe and require immediate medical attention.

This comprehensive guide outlines the critical signs of brain aneurysm that everyone should recognize, helping you understand when to seek emergency medical care.

1. Sudden, Severe Headache

The most characteristic symptom of a ruptured brain aneurysm is an extremely severe, sudden headache often described as “the worst headache of your life.” This isn’t a typical headache that builds gradually—it strikes suddenly and intensely, like a thunderclap.

What makes this headache unique:

• It reaches maximum intensity within seconds to minutes
• The pain is often described as explosive or like being hit in the head
• It’s significantly more severe than any headache you’ve experienced before
• The pain may be localized to one area or spread throughout the entire head
• It doesn’t respond well to typical pain relievers

This type of headache, medically termed a “thunderclap headache,” occurs when an aneurysm ruptures and blood leaks into the space around the brain. If you experience this symptom, seek emergency medical care immediately, as it can indicate a life-threatening rupture.

2. Vision Problems and Changes

Vision disturbances are among the early symptoms of brain aneurysm, particularly when an unruptured aneurysm grows large enough to press on the optic nerve or other structures affecting vision. These visual changes can manifest in several ways and should never be dismissed.

Common vision-related symptoms include:

• Double vision (diplopia): Seeing two images of a single object, which may occur when an aneurysm affects the nerves controlling eye movement
• Blurred or decreased vision: A general loss of visual clarity or sharpness in one or both eyes
• Dilated pupil: One pupil may become noticeably larger than the other
• Drooping eyelid: Also called ptosis, this can occur on one side of the face
• Loss of peripheral vision: Decreased ability to see objects to the side while looking straight ahead
• Sensitivity to light: Increased discomfort or pain when exposed to bright lights

These symptoms occur because aneurysms can develop near the optic nerves or the nerves that control eye muscles. An aneurysm in the internal carotid artery or posterior communicating artery is particularly likely to cause vision problems. Any sudden or progressive vision changes warrant immediate medical evaluation.

3. Neck Pain and Stiffness

Neck pain and stiffness, especially when accompanied by other symptoms, can be a significant warning sign of a brain aneurysm. This symptom is particularly common when an aneurysm ruptures and blood irritates the meninges—the protective membranes covering the brain and spinal cord.

Characteristics of aneurysm-related neck pain:

• Severe stiffness that makes it difficult or painful to move the neck
• Pain that may radiate from the head down to the neck and shoulders
• Difficulty touching the chin to the chest
• Stiffness that appears suddenly rather than developing gradually
• Pain that may be accompanied by fever in some cases

This symptom, known medically as nuchal rigidity or meningismus, occurs because blood in the subarachnoid space (the area between the brain and skull) irritates the nerve endings in the meninges. While neck stiffness can have many causes, when it appears suddenly alongside a severe headache, it’s considered a medical emergency requiring immediate evaluation.

4. Nausea and Vomiting

Nausea and vomiting are common symptoms of brain aneurysm, particularly when the aneurysm ruptures. Unlike typical stomach upset, aneurysm-related nausea often appears suddenly and is typically accompanied by other neurological symptoms.

Key features of this symptom:

• Sudden onset of severe nausea without an obvious digestive cause
• Vomiting that occurs alongside a severe headache
• Persistent nausea that doesn’t improve with typical remedies
• Vomiting that may be projectile in nature
• Symptoms that worsen with movement or changes in position

These symptoms occur due to increased intracranial pressure (pressure inside the skull) or irritation of brain structures that control nausea. When the brain’s vomiting center is affected by bleeding or pressure from an aneurysm, it can trigger these symptoms. The combination of severe headache, neck stiffness, nausea, and vomiting is particularly concerning for a ruptured aneurysm and requires emergency medical attention.

5. Seizures or Convulsions

Seizures can be a frightening and serious symptom of a brain aneurysm, occurring in approximately 10-25% of people who experience an aneurysm rupture. A seizure happens when there’s abnormal electrical activity in the brain, which can be triggered by bleeding, increased pressure, or irritation of brain tissue.

Types of seizures associated with brain aneurysms:

• Generalized seizures: Affecting the entire brain, causing loss of consciousness and convulsions throughout the body
• Focal seizures: Starting in one area of the brain, potentially causing localized symptoms like jerking of one limb or facial twitching
• Status epilepticus: Prolonged or repeated seizures without recovery in between, which is a medical emergency

What does an aneurysm-related seizure look like:

• Sudden loss of consciousness
• Uncontrollable jerking movements of the arms and legs
• Stiffening of the body
• Loss of bladder or bowel control
• Temporary confusion or memory loss after the seizure
• Tongue biting or foaming at the mouth

Seizures can occur immediately after an aneurysm ruptures or sometimes develop hours to days later. Any first-time seizure, especially in adults without a history of epilepsy, requires immediate emergency evaluation to rule out serious causes like a brain aneurysm.

6. Loss of Consciousness or Altered Mental State

A change in consciousness level or mental state is one of the most serious signs of aneurysm, particularly indicating a ruptured aneurysm with significant bleeding. This symptom can range from mild confusion to complete unconsciousness and represents a medical emergency.

Variations of altered consciousness include:

• Brief loss of consciousness: Fainting or blacking out for a few seconds to minutes
• Prolonged unconsciousness: Being unresponsive for extended periods, potentially leading to coma
• Confusion or disorientation: Not knowing where you are, what day it is, or recognizing familiar people
• Difficulty staying awake: Extreme drowsiness or lethargy that’s unusual for the person
• Decreased alertness: Slow responses to questions or stimuli
• Agitation or unusual behavior: Acting in ways that are out of character

Why this happens: When an aneurysm ruptures, bleeding into the brain increases pressure inside the skull and can disrupt the normal functioning of brain cells. Large amounts of bleeding can affect the brain’s arousal systems, which regulate consciousness. The severity of altered consciousness often correlates with the amount of bleeding and the location of the aneurysm.

Even brief episodes of loss of consciousness associated with a severe headache should be treated as a potential ruptured aneurysm and require immediate emergency medical care.

7. Sensitivity to Light (Photophobia)

Photophobia, or extreme sensitivity to light, is a common but often overlooked symptom of brain aneurysm. People experiencing this symptom find that normal lighting levels cause significant discomfort, pain, or the need to close their eyes or look away.

How photophobia manifests:

• Severe discomfort or pain in the eyes when exposed to light
• Strong desire to be in dark rooms or wear sunglasses even indoors
• Squinting or inability to keep eyes open in normal lighting
• Headache that worsens with light exposure
• Tearing or watering of the eyes in response to light

This symptom typically occurs when an aneurysm ruptures and blood in the subarachnoid space irritates the meninges (the protective membranes covering the brain). This irritation can make the nervous system hypersensitive to various stimuli, including light. Photophobia is particularly common in subarachnoid hemorrhage caused by a ruptured aneurysm and is often accompanied by severe headache and neck stiffness—a triad of symptoms that strongly suggests this diagnosis.

8. Pain Above and Behind the Eye

Localized pain above or behind one eye is one of the early symptoms of brain aneurysm that can occur even before rupture, particularly when an aneurysm grows in size or develops in specific locations.

Characteristics of this pain:

• Deep, aching pain located above, behind, or around one eye
• Pain that may be constant or intermittent
• Discomfort that doesn’t respond well to typical pain medications
• May be accompanied by vision changes in the same eye
• Can progressively worsen over time
• Different from typical sinus pain or migraine patterns

This symptom most commonly occurs with aneurysms located in the following areas:

• Internal carotid artery: Near the base of the brain, close to the eye structures
• Posterior communicating artery: Running near the third cranial nerve, which controls eye movement and pupil size
• Ophthalmic artery: Supplying blood to the eye and surrounding structures

When an unruptured aneurysm in these locations grows, it can press on nearby pain-sensitive structures or the nerves supplying the eye area, causing this distinctive pain. While this symptom alone doesn’t confirm an aneurysm, persistent or unexplained pain behind the eye, especially with other symptoms, warrants medical evaluation.

9. Weakness or Numbness on One Side of the Body

Unilateral weakness or numbness—affecting only one side of the face or body—is a critical warning sign that can indicate a brain aneurysm or its complications. This symptom can occur with unruptured aneurysms that compress brain tissue or, more commonly, with ruptured aneurysms that cause bleeding and damage to specific brain regions.

How this symptom presents:

• Facial drooping: One side of the face may droop or feel numb, making it difficult to smile symmetrically
• Arm or leg weakness: Difficulty lifting or moving one arm or leg, or inability to grip objects
• Numbness or tingling: Reduced sensation on one side of the face, arm, or leg
• Coordination problems: Difficulty with fine motor skills on the affected side
• Sudden onset: These symptoms typically appear suddenly rather than gradually

Why it occurs:

The brain’s motor cortex controls movement on the opposite side of the body. When an aneurysm ruptures or presses on specific areas of the brain, it can disrupt the signals controlling movement and sensation. Different aneurysm locations produce different patterns of weakness:

• Middle cerebral artery aneurysms often cause weakness in the arm and face
• Anterior cerebral artery aneurysms typically affect the leg more than the arm
• Complications like vasospasm (blood vessel narrowing after rupture) can cause stroke-like symptoms

This symptom closely mimics a stroke, and indeed, a ruptured brain aneurysm is a type of stroke called a hemorrhagic stroke. Any sudden weakness or numbness on one side of the body requires immediate emergency evaluation.

10. Difficulty Speaking or Understanding Speech

Communication difficulties, including problems with speaking or understanding language, can be significant symptoms of aneurysm, particularly when the aneurysm affects the language centers of the brain.

Types of speech and language problems:

• Slurred speech (dysarthria): Words come out unclear, mumbled, or difficult for others to understand
• Difficulty finding words (anomia): Knowing what you want to say but being unable to retrieve the right words
• Inability to speak (aphasia): Complete or nearly complete loss of the ability to produce speech
• Nonsensical speech: Speaking in sentences that don’t make sense or using incorrect words
• Difficulty understanding: Unable to comprehend what others are saying, even simple instructions
• Difficulty reading or writing: Loss of ability to read text or write coherent sentences

Why language problems occur:

Language functions are typically controlled by specific areas in the left hemisphere of the brain (in most right-handed people and many left-handed people), particularly in regions called Broca’s area and Wernicke’s area. An aneurysm in the middle cerebral artery—one of the most common locations—can affect these language centers. When an aneurysm ruptures or causes bleeding in these areas, it can disrupt normal language function.

Additional considerations:

• Language problems may appear suddenly alongside other symptoms like headache or weakness
• The person experiencing these symptoms may not realize they’re having difficulty communicating
• Family members or bystanders often notice these symptoms first
• These symptoms are considered stroke warning signs and require emergency care

Speech and language difficulties can be temporary or permanent depending on the extent of damage and how quickly treatment is received.

What Causes a Brain Aneurysm

Understanding what causes a brain aneurysm can help identify risk factors and potentially prevent this serious condition. While the exact cause isn’t always clear, aneurysms develop when the wall of a blood vessel in the brain becomes weakened. Several factors contribute to this weakening:

Genetic and Congenital Factors:

• Inherited conditions: Certain genetic disorders increase aneurysm risk, including polycystic kidney disease, Ehlers-Danlos syndrome, Marfan syndrome, and fibromuscular dysplasia
• Family history: Having a first-degree relative (parent, sibling, or child) with a brain aneurysm increases your risk by 2-5 times
• Congenital abnormalities: Being born with abnormalities in the arterial walls or abnormal blood vessel connections

Acquired Risk Factors:

• High blood pressure (hypertension): The most significant modifiable risk factor, chronic high blood pressure weakens arterial walls over time
• Smoking: Tobacco use damages blood vessels and significantly increases aneurysm risk
• Age: Risk increases with age, particularly after 40 years old
• Gender: Women are more likely to develop brain aneurysms than men, especially after menopause
• Atherosclerosis: Buildup of fatty deposits in blood vessels can weaken arterial walls
• Drug abuse: Particularly cocaine and amphetamines, which can damage blood vessels and spike blood pressure
• Excessive alcohol consumption: Heavy drinking can raise blood pressure and weaken blood vessel walls

Other Contributing Factors:

• Head trauma or injury to blood vessels
• Infections that affect the arterial wall
• Brain tumors that press on blood vessels
• High estrogen levels (which may explain higher rates in post-menopausal women)
• Previous aneurysm or family history of aneurysm rupture

Most brain aneurysms develop at arterial branching points where blood vessels fork, as these areas experience the most hemodynamic stress. The constant pressure and turbulent blood flow at these junction points can gradually weaken the vessel wall, causing it to balloon outward and form an aneurysm.

Prevention Strategies

While not all brain aneurysms can be prevented, especially those caused by genetic factors, there are several evidence-based strategies to reduce your risk or prevent rupture if you have an existing aneurysm:

Control Blood Pressure:

• Monitor your blood pressure regularly at home and during medical appointments
• Maintain blood pressure below 120/80 mm Hg through lifestyle changes and medication if prescribed
• Follow your doctor’s recommendations for blood pressure management
• Reduce sodium intake and follow a heart-healthy diet

Quit Smoking and Avoid Tobacco:

• Stop smoking immediately—this is one of the most important preventive measures
• Seek support through smoking cessation programs, counseling, or support groups
• Avoid secondhand smoke exposure
• Remember that smoking not only increases aneurysm formation risk but also significantly increases rupture risk

Avoid Drug and Alcohol Abuse:

• Avoid recreational drugs, especially cocaine and amphetamines, which can cause sudden blood pressure spikes
• Limit alcohol consumption to moderate levels (no more than one drink per day for women, two for men)
• Seek help for substance abuse problems if needed

Maintain a Healthy Lifestyle:

• Eat a balanced diet rich in fruits, vegetables, whole grains, and lean proteins
• Exercise regularly with your doctor’s approval, aiming for at least 150 minutes of moderate activity per week
• Maintain a healthy weight to reduce cardiovascular strain
• Manage stress through relaxation techniques, meditation, or counseling
• Get adequate sleep (7-9 hours nightly)

Medical Monitoring:

• Inform your doctor if you have a family history of brain aneurysms or related conditions
• Discuss screening options if you have multiple risk factors or a strong family history
• If you have a known unruptured aneurysm, follow your doctor’s monitoring schedule carefully
• Attend all recommended follow-up appointments and imaging studies
• Report any new or worsening symptoms immediately

Special Precautions for Those with Known Aneurysms:

• Avoid activities that cause sudden, extreme increases in blood pressure (heavy lifting, straining during bowel movements, certain extreme sports)
• Discuss with your doctor which activities are safe for you
• Be aware of warning signs and have an action plan for emergencies
• Consider wearing a medical alert bracelet indicating your condition

Remember that having risk factors doesn’t guarantee you’ll develop an aneurysm, and some people with no known risk factors still develop them. Regular medical check-ups and open communication with your healthcare provider are essential for early detection and prevention.

Frequently Asked Questions

Can you feel a brain aneurysm before it ruptures?

Most unruptured brain aneurysms cause no symptoms and cannot be felt. However, larger unruptured aneurysms may cause warning symptoms such as pain above or behind the eye, vision changes, numbness, or weakness. Some people experience what doctors call “sentinel headaches”—small warning headaches that occur days or weeks before a major rupture.

What does an aneurysm headache feel like?

An aneurysm rupture typically causes a sudden, extremely severe headache often described as “the worst headache of your life” or like being hit with a baseball bat. It reaches maximum intensity within seconds, unlike typical headaches that build gradually. This “thunderclap headache” is the hallmark symptom of a ruptured brain aneurysm and requires immediate emergency care.

Are brain aneurysms always fatal?

No, brain aneurysms are not always fatal. Many unruptured aneurysms never rupture and may be monitored or treated preventively. However, ruptured aneurysms are serious—approximately 25-50% of people who experience a rupture die, and many survivors have permanent neurological damage. The key is early detection and immediate treatment when rupture occurs.

Who is at highest risk for brain aneurysms?

People at highest risk include those with a family history of aneurysms, smokers, people with uncontrolled high blood pressure, women (especially post-menopausal), individuals over 40 years old, people with certain genetic disorders (like polycystic kidney disease), and those who abuse drugs or alcohol. Having multiple risk factors increases overall risk.

Can stress cause a brain aneurysm to rupture?

While stress alone doesn’t cause aneurysms, sudden increases in blood pressure from severe emotional stress, extreme physical exertion, or straining can potentially trigger rupture in an existing aneurysm. This is why managing stress and avoiding activities that cause sudden blood pressure spikes is important for those with known aneurysms.

How quickly do you need treatment for a ruptured aneurysm?

A ruptured brain aneurysm is a medical emergency requiring immediate treatment—call emergency services (911 in the US) right away. Every minute counts, as early treatment significantly improves survival rates and reduces the risk of permanent brain damage. Don’t wait to see if symptoms improve or try to drive yourself to the hospital.

Can you have a brain aneurysm and not know it?

Yes, absolutely. Most brain aneurysms are unruptured and cause no symptoms, so many people live with them without knowing. These “silent” aneurysms are often discovered incidentally during brain imaging tests performed for other reasons. Some estimates suggest that 1-2% of the population has an unruptured brain aneurysm.

What should I do if I think I have symptoms of a brain aneurysm?

If you experience sudden, severe headache, vision changes, loss of consciousness, seizures, or other concerning symptoms mentioned in this article, call emergency services immediately. Don’t wait or try to self-diagnose. For less severe but persistent symptoms like localized eye pain or vision changes, schedule an urgent appointment with your doctor. When in doubt, always err on the side of caution and seek medical evaluation.

References:

• Mayo Clinic – Brain Aneurysm
• National Institute of Neurological Disorders and Stroke – Cerebral Aneurysms
• Johns Hopkins Medicine – Cerebral Aneurysm
• American Association of Neurological Surgeons – Cerebral Aneurysm
• American Stroke Association – Hemorrhagic Strokes
• NHS – Brain Aneurysm