On this page
What is Aneurysm?
Aneurysm is the abnormal bulging or dilation of a blood vessel caused by a weakness in its wall, typically occurring at points where the vessel branches off into smaller vessels.
As blood continuously flows through the weakened vessel, arterial pressure gradually pushes a small area of the wall outward, much like air inflating a balloon.
Any blood vessel in the body can theoretically develop an aneurysm, although this phenomenon most commonly affects two specific areas:
- the abdominal aorta (the aorta being the main artery that carries blood from the heart to the rest of the body),
- the brain, which is the focus of this article.
In medical terminology, an aneurysm that develops inside the brain is called an intracranial aneurysm, or more simply, a cerebral aneurysm.
The majority of brain aneurysms produce no noticeable symptoms until they rupture, a dramatic event that suddenly triggers a life threatening condition known as subarachnoid hemorrhage. When this bleeding occurs, it can cause extensive brain damage and produce symptoms such as:
- a sudden, excruciating headache, often described by patients as feeling like a lightning bolt out of a clear sky, similar to a sudden blow to the head followed by a blinding pain unlike anything ever experienced before,
- a stiff neck,
- nausea and vomiting,
- pain triggered by exposure to light,
- loss of consciousness and seizures.
This is a condition with an unfortunately grim prognosis. Current data suggest that roughly three out of five people who experience a subarachnoid hemorrhage die within two weeks, and about half of those who survive are left with severe, permanent brain damage and lasting disability.
For this reason, the rupture of a brain aneurysm is always considered a medical emergency. If you suspect a brain hemorrhage caused by a ruptured aneurysm, whether in yourself or someone else, you should call emergency services immediately.
It is important to emphasize, however, that the vast majority of brain aneurysms never rupture and never cause any noticeable symptoms at all. Aneurysms of this type are frequently discovered incidentally, during imaging tests performed for entirely unrelated reasons. In some of these cases, treatment may still be recommended for an aneurysm that has not ruptured, specifically to prevent it from rupturing in the future.
Causes
Brain aneurysms develop as a consequence of thinning and progressive weakening of the arterial walls. They often form at points where arteries branch, since blood vessels tend to be structurally weaker at these junctions. Aneurysms can technically form anywhere in the brain, but in the majority of cases they affect the arteries located at the base of the organ, in a network of vessels known as the Circle of Willis.
The exact underlying causes that lead to weakening of the vascular walls are still not completely understood, although researchers have identified several important risk factors, including:
- smoking,
- high blood pressure (hypertension),
- a family history of brain aneurysms.
In some cases, an aneurysm may originate from a congenital vascular weakness, meaning a structural defect that has been present in the vessel wall since birth.
Risk Factors
Determining exactly how many people have a brain aneurysm is difficult, largely because the condition typically causes no symptoms and is usually detected only incidentally or after it has already ruptured.
Some experts estimate that as many as 1 in 20 people may harbor an unruptured brain aneurysm at some point in their lives, while other studies suggest a much lower frequency, closer to 1 in 100. Fortunately, the number of aneurysms that actually go on to rupture is far smaller than the overall number of people who have one.
Several factors can contribute to the progressive weakening of arterial walls and therefore increase the risk of developing a brain aneurysm. These include:
-
Age: The risk increases notably after the age of 40, likely reflecting the cumulative effect of decades of arterial wear and blood pressure exposure.
-
Sex: Women have a higher risk of developing brain aneurysms compared to men, a difference that is likely related to the decline in estrogen that occurs after menopause. Estrogen appears to play a protective role in maintaining the elasticity and structural integrity of blood vessel walls.
-
Smoking: Studies have consistently shown that the majority of people diagnosed with a brain aneurysm currently smoke or have smoked in the past. The precise mechanism remains unclear, but it may be related to chemicals in tobacco smoke that directly damage the walls of blood vessels over time.
-
High blood pressure: Hypertension is a well established risk factor because it directly increases the force exerted by blood against the arterial walls, accelerating wear on already weakened areas.
-
Hardening of the arteries (atherosclerosis): The buildup of fatty deposits inside arteries can weaken vessel walls and contribute to aneurysm formation.
-
Family history of aneurysm, particularly in first degree relatives such as parents or siblings, although statistically the overall increase in individual risk from family history alone remains relatively modest.
-
Drug abuse, particularly cocaine use, which sharply raises blood pressure and causes inflammation of blood vessel walls.
-
Head injuries: This is a rare cause of brain aneurysm, but it remains a documented possibility, particularly following severe trauma affecting the base of the skull.
-
Excessive consumption of alcohol.
-
Certain specific bloodstream infections, which can lead to what are known as mycotic (infectious) aneurysms.
Several inherited congenital conditions are also known to increase the risk of developing a brain aneurysm, including:
-
Inherited connective tissue disorders, such as Ehlers-Danlos syndrome, which weakens the structural integrity of blood vessels throughout the body.
-
Polycystic kidney disease: This inherited disorder causes fluid filled cysts to form in the kidneys and is strongly associated with elevated blood pressure, both of which contribute to aneurysm risk.
-
Coarctation of the aorta: In this condition, the aorta, the main artery that carries oxygen rich blood from the heart to the rest of the body, becomes abnormally narrowed, leading to increased pressure elsewhere in the arterial system.
-
Cerebral arteriovenous malformation (AVM): This is an abnormal tangle of connections between arteries and veins in the brain that disrupts normal blood flow patterns and can place additional stress on nearby vessels.
Symptoms
A brain aneurysm is only rarely symptomatic, at least until the moment it ruptures. Unruptured aneurysms occasionally cause symptoms, but generally only when they grow large enough to press directly on surrounding brain tissue or nerves.
Possible symptoms of an unruptured brain aneurysm include:
- visual disturbances, such as vision loss or double vision,
- pain above or around the eye,
- dilation of the pupil (mydriasis),
- numbness or weakness on one side of the face,
- drooping eyelid (ptosis),
- difficulty speaking,
- headache,
- loss of balance,
- difficulty concentrating or short term memory problems.
If you experience any symptoms that could be consistent with a brain aneurysm, contact your doctor promptly. Although the majority of aneurysms never rupture, it remains important to have them evaluated in case treatment is warranted to reduce future risk.
Rupture of an Aneurysm
The rupture of a brain aneurysm is typically announced by a sudden, excruciating headache, often compared to a violent blow to the head, producing a blinding pain unlike anything the person has ever experienced before. Patients frequently describe it as “the worst headache of my life”.
Other symptoms of a ruptured brain aneurysm also tend to appear suddenly and abruptly, and may include:
- a general feeling of being unwell,
- a sudden and extremely severe headache,
- nausea and vomiting,
- neck stiffness,
- blurred or double vision,
- photophobia (extreme sensitivity to light),
- seizures,
- ptosis (excessive drooping of the upper eyelid),
- loss of consciousness,
- weakness affecting one side of the body or a single limb,
- confusion.
The rupture of a brain aneurysm is always a medical emergency. Call emergency services immediately if you or someone near you experiences symptoms consistent with a ruptured brain aneurysm. Do not wait to see if symptoms improve on their own, as every minute of delay can significantly worsen the outcome.
Leaking (Sentinel) Aneurysm
In some cases, an aneurysm may begin to leak a small amount of blood before undergoing a full rupture. This so called sentinel leak typically causes a sudden and very intense headache that can be mistaken for a routine, though severe, headache.
Unfortunately, this initial minor bleeding is almost always followed, sometimes within hours or days, by a full and much more dangerous rupture. For this reason, any sudden, unusually severe headache, even one that seems to improve on its own, should be taken extremely seriously and evaluated by a physician without delay.
When to Call a Doctor
The rupture of a brain aneurysm is always considered a medical emergency, particularly given that in roughly half of all cases, rupture of a brain aneurysm ultimately proves fatal.
It is therefore absolutely essential to seek immediate emergency medical care, either by going to the nearest emergency department or by calling emergency services, if you experience any of the following:
- a sudden, excruciating headache unlike any experienced before,
- loss of consciousness,
- seizures.
Do not attempt to drive yourself to the hospital if you are experiencing these symptoms. Call for emergency transport so that appropriate care can begin as quickly as possible, ideally even before arrival at the hospital.
Dangers and Complications
When a brain aneurysm ruptures, the bleeding itself usually lasts only a few seconds. However, even this brief exposure to blood can directly damage or kill surrounding brain cells, while also sharply raising the pressure inside the skull, a condition known as intracranial hypertension. If this pressure rises too much, it can interrupt the normal supply of blood and oxygen to the brain, potentially leading to loss of consciousness or death.
Once an aneurysm has ruptured, there is a significant risk that it will rupture again and bleed a second time into the brain. Additional aneurysms may also develop elsewhere in the vascular system over time. Most commonly, rupture leads to a subarachnoid hemorrhage, meaning bleeding into the space between the skull and the surface of the brain.
A serious delayed complication of subarachnoid hemorrhage is hydrocephalus, in which an excessive buildup of cerebrospinal fluid inside the skull causes the brain’s fluid filled cavities, known as ventricles, to expand. This expansion can compress surrounding brain tissue and cause additional neurological damage if not promptly treated, usually through drainage of the excess fluid.
Another serious delayed complication following rupture is vasospasm, a condition in which other blood vessels in the brain suddenly constrict, restricting blood flow to vital areas of the brain. This reduction in blood flow can lead to stroke or permanent tissue damage, and it typically develops within the first one to two weeks after the initial hemorrhage, requiring close monitoring in an intensive care setting.
Diagnosis
The diagnostic pathway for a brain aneurysm differs significantly depending on whether the patient presents as an emergency, with suspected rupture, or is being evaluated electively for an aneurysm that has not caused any symptoms. In both scenarios, the accuracy of modern imaging technology is absolutely essential for determining the most appropriate treatment strategy.
Emergency Diagnostic Tests
When a patient presents with a sudden, “thunderclap” headache, the first line diagnostic test is a computed tomography (CT) scan of the brain performed without contrast dye. This test is extremely sensitive for detecting the presence of blood in the subarachnoid space during the first several hours after the bleeding event occurs.
If the CT scan comes back negative but clinical suspicion for aneurysm rupture remains high, standard protocol calls for a lumbar puncture (spinal tap). Analysis of the cerebrospinal fluid obtained during this procedure can reveal the presence of red blood cells or breakdown products of hemoglobin, known as xanthochromia, which confirms that bleeding has occurred even when it is not visible on imaging alone.
Advanced Vascular Imaging
Once bleeding has been confirmed, doctors need to map the entire vascular tree in order to precisely locate the aneurysm responsible. The most commonly used techniques include:
-
CT angiography (CTA): This test uses an intravenous iodine based contrast dye to create detailed three dimensional reconstructions of the brain’s blood vessels. It is fast to perform and provides crucial information about the exact shape and size of the aneurysm.
-
Digital subtraction angiography (DSA): This remains the diagnostic gold standard for evaluating brain aneurysms. A thin catheter, usually inserted through the femoral or radial artery, is guided up into the brain’s blood vessels, where contrast dye is injected directly into the cerebral arteries. This test provides the highest possible spatial and temporal resolution, allowing physicians to precisely plan either surgical or endovascular treatment.
Screening and Evaluation of Unruptured Aneurysms
For aneurysms that have not ruptured, which are often discovered incidentally during imaging performed for unrelated reasons, magnetic resonance imaging (MRI) using specialized vascular sequences, known as MR angiography, is generally the preferred approach. This test does not expose the patient to ionizing radiation, making it particularly well suited for long term monitoring over time.
Proactive screening for brain aneurysms is currently recommended only for specific, carefully selected groups, particularly individuals with two or more first degree relatives who have been diagnosed with a brain aneurysm, or patients with genetic conditions known to predispose to aneurysm formation, such as autosomal dominant polycystic kidney disease.
Treatment
The primary goals of treatment are to exclude the aneurysm from the bloodstream, thereby preventing bleeding or re-bleeding in cases where rupture has already occurred, and to manage any resulting neurological complications. The choice between different treatment approaches depends on the location and shape of the aneurysm, as well as the patient’s overall health and specific circumstances.
Endovascular Approach (Minimally Invasive)
Today, endovascular treatment represents the first choice in the majority of cases, largely due to its reduced invasiveness compared to open surgery. The entire procedure is performed from inside the blood vessels themselves, without any need to open the skull.
-
Coil embolization (coiling): Thin platinum coils are threaded through a catheter and placed inside the aneurysm sac, where they promote the formation of a blood clot that seals off the aneurysm from normal circulation.
-
Flow diverters: These are specialized, densely woven stents that are positioned in the main artery directly in front of the aneurysm’s opening. They redirect blood flow away from the aneurysm sac, encouraging its gradual closure while promoting the natural reconstruction of the healthy vessel wall over time.
-
Endosaccular devices (such as the WEB device): These represent more recent innovations that allow doctors to treat wide necked aneurysms using a single basket shaped device, which is particularly useful in complex anatomical configurations that are difficult to treat with traditional coiling alone.
Traditional Surgery (Clipping)
Although more invasive than endovascular options, surgical clipping remains a fundamental and highly effective technique. During this procedure, performed through a craniotomy (a surgical opening in the skull), the neurosurgeon places a small metal clip across the neck of the aneurysm, permanently sealing it off from normal blood flow. This method is often preferred for aneurysms with irregular shapes, those located in more superficial and accessible positions, or in cases where it is also necessary to remove a blood clot that is compressing surrounding brain tissue.
Clinical and Pharmacological Management
When rupture has occurred, treatment does not end once the aneurysm itself has been closed off. The patient must be closely monitored in an intensive care setting to prevent vasospasm, the dangerous narrowing of blood vessels that can lead to secondary strokes. Administration of nimodipine, a calcium channel blocker, is the standard protocol used to improve neurological outcomes in these patients.
In cases where hydrocephalus develops due to excess fluid accumulation, it may become necessary to insert a temporary or permanent ventricular drain to manage intracranial pressure and prevent further neurological damage.
Observation and Risk Management
Not every aneurysm discovered incidentally requires immediate treatment. When the estimated risk of rupture is considered very low, based on factors such as the aneurysm’s size, shape, and location, doctors often recommend active surveillance instead. This approach involves periodic imaging studies to monitor for any changes, combined with rigorous management of modifiable risk factors such as blood pressure and smoking.
Lifestyle Factors
Lifestyle modification is an integral part of treatment and has a genuinely significant clinical impact on the long term stability of the vascular wall:
-
Blood pressure control: This is the single most critical factor. Keeping blood pressure within normal physiological limits dramatically reduces the ongoing stress placed on the aneurysm wall.
-
Smoking cessation: Smoking is directly linked to both the growth and the rupture of brain aneurysms. Quitting smoking is essential for reducing the risk of future complications, regardless of whether the aneurysm has already been treated.
-
Avoiding recreational drugs: Substances such as cocaine and amphetamines cause extremely dangerous spikes in blood pressure that can precipitate aneurysm rupture.
-
Physical activity: Regular, moderate aerobic exercise is generally recommended, while intense isometric exertion, such as extreme heavy weightlifting, should be avoided, since it can cause sudden, sharp increases in intracranial pressure.
Prevention
The best way to prevent a brain aneurysm from forming, or to reduce the risk that an existing aneurysm will grow larger and eventually rupture, is to avoid activities and risk factors known to damage blood vessels, including:
- smoking,
- a diet high in unhealthy fats,
- uncontrolled high blood pressure,
- being overweight or obese.
Maintaining regular checkups with your doctor, particularly if you have known risk factors such as a family history of aneurysms or an underlying genetic condition, can also help ensure that any developing problems are caught and addressed as early as possible.
Frequently Asked Questions
Why do I get sharp pains in my head that only last a few seconds?
Brief, sharp pains in the head lasting only a few seconds can be caused by several different factors, including muscle tension, cluster headaches, or other primary headache disorders. It is important to keep track of how often these episodes occur and under what circumstances, so you can report this information accurately to your doctor if the pattern continues or worsens.
What causes pain in the left or right temple?
Possible causes of temple pain include migraines, tension headaches, or muscular tension in the jaw or scalp area. In some cases, temple pain can be related to more serious underlying conditions, such as temporal arteritis, and may require prompt medical evaluation, particularly in older adults.
What does it mean if my head is pulsing without any pain?
Experiencing a pulsing sensation in the head without accompanying pain can sometimes be a sign of stress, muscle tension, or heightened bodily awareness and sensitivity. Even so, it is a good idea to mention this symptom to your doctor, particularly if it is new, persistent, or accompanied by any other neurological symptoms.
Can sharp head pains be a symptom of a brain aneurysm?
Yes, sharp head pains can occasionally be a symptom of a brain aneurysm, although this is quite rare. It is essential to consult a doctor if you experience frequent or unusually intense head pains, so that appropriate tests can be performed to rule out serious underlying causes.
What is a brain aneurysm?
A brain aneurysm is an abnormal bulging of a blood vessel wall, resulting in a balloon like structure that tends to swell further under the ongoing pressure of blood flow. Most brain aneurysms develop silently and are only discovered incidentally or after they rupture.
What are the symptoms of a brain aneurysm?
The mere presence of an unruptured aneurysm typically causes no symptoms at all, unless it grows large enough to press on surrounding tissue. In that case, depending on its exact location, symptoms may include pain around or behind the eye, a dilated pupil, visual disturbances, or a tingling sensation on one side of the face. If the aneurysm ruptures, however, the resulting symptoms are dramatic and constitute a serious medical emergency: a sudden and excruciating headache, nausea and vomiting, neck stiffness, visual disturbances, sensitivity to light, seizures, a drooping eyelid (ptosis), fainting, and confusion.
What causes brain aneurysms?
The precise underlying causes of aneurysm formation generally remain unknown. While some aneurysms are congenital, meaning they are present from birth, many others form gradually over the course of a person’s life for reasons that are not yet fully understood. Among the most commonly recognized risk factors are advancing age (aneurysms are uncommon in children and adolescents), smoking, alcohol and drug use, and high blood pressure.
What are the potential consequences of a brain aneurysm?
The greatest danger is associated with rupture, which unfortunately proves fatal in the majority of cases, and in the remaining cases carries a significant risk of severe, permanent complications. When only a partial tear occurs, resulting in limited bleeding, the prognosis remains serious but allows for somewhat greater optimism, provided the condition is diagnosed and treated rapidly.
Is it possible to prevent a brain aneurysm?
Beyond maintaining a healthy lifestyle to reduce the impact of known risk factors, there is unfortunately little else that can be done to prevent aneurysm formation entirely. In individuals considered to be at higher risk, for example due to a strong family history or the presence of associated genetic conditions, periodic imaging studies may be recommended to detect the presence of any still unruptured aneurysms before they become a problem.
When is it appropriate to see a doctor for a headache?
It is important to consult a doctor about a headache if the pain is severe, comes on suddenly or feels excruciating (for example, described as the “worst headache of your life”), or is accompanied by symptoms such as mental confusion, fever, neck stiffness, or visual problems, particularly in a patient with no prior history of migraines or recurring headaches. In these situations, immediate medical evaluation is essential and should not be delayed.
What symptoms should alert me to potential seizures or serious neurological conditions?
Symptoms that require urgent medical attention include a sudden and severe headache, especially one perceived as the worst headache of your life, blurred or double vision, mental confusion, difficulty speaking or moving, weakness in the limbs, neck stiffness, high fever, and nausea. These symptoms can indicate serious underlying neurological conditions, and immediate medical evaluation is necessary to rule out life threatening causes.
How can I manage anxiety related to the fear of serious illness?
To manage anxiety related to the fear of serious illness, it can be helpful to practice relaxation techniques such as meditation, yoga, or deep breathing exercises. Talking with a mental health professional can also provide valuable support and practical strategies for coping with these fears. Additionally, maintaining a healthy lifestyle, including regular physical activity and a balanced diet, can help improve overall well being and reduce anxiety over time.
