Brain aneurysm is a rare condition which may potentially turn out to be life-threatening. This condition is also labelled as intracranial aneurysm referring to the interior portion of the skull where this condition occurs. Aneurysms often turn fatal if they are not diagnosed and treated at a proper time.

Also known as Cerebral Aneurysm, Brain Aneurysm is an abnormal ballooning of an artery that occurs from a weakened or thin section in the wall of blood vessels in the brain. The bulge puts pressure on the brain tissues and nerves. Abnormal swelling increases the likelihood of the aneurysm bursting or leaking.  

A ruptured aneurysm may result in life-threatening health issues like subarachnoid haemorrhage, coma, brain damage, or even death.  Brain aneurysms may occur in any spot in the brain, but in maximum cases, intracranial aneurysms develop in the major blood vessels along the skull and its base.

There are five types of brain aneurysms, as stated below:

1. Saccular Aneurysm

The most common form of a brain aneurysm is the 'saccular’ aneurysm. They are also called 'berry' aneurysms, as they resemble berries or sacs that stick out from the side of a blood vessel wall. Berry aneurysms are related to development and rupture type. These aneurysms are also the leading causes of non-traumatic subarachnoid haemorrhage (SAH). Saccular aneurysms typically develop along the weaker areas of the arterial wall.

2. Fusiform Aneurysm

Also called a dissecting aneurysm, a 'fusiform' aneurysm resembles expanded blood vessels in all directions. Compared to saccular aneurysms, they are less common and are generally caused by injuries to the interior layers of blood vessels. They rarely cause SAH but can result in stroke as they grow in size.

3. Mycotic Aneurysm

Also called infectious aneurysms, they are a rare form of a saccular aneurysm. This type occurs from any artery walls in any part of the body which has been infected, such as the heart. They can be caused by different infectious agents as well. Mycotic aneurysms may occur in multiple numbers along the superficial parts of the brain arteries.

4. PseudoAneurysm

A pseudoaneurysm is a growth of an artery wall which does not affect all the layers of the wall. Generally, they involve only the exterior walls of the brain arteries and follow the slitting of the vessel wall. The ballooning may block blood flow in the artery. 

5. Blister Aneurysm

Blister aneurysms may grow anywhere on the blood vessels in the brain. These aneurysms may cause more incidence of bleeding as well as increased mortality rate.

Now that you know the types of brain aneurysms, take a look at their symptoms.

In general, the symptoms of an aneurysm vary between unruptured, ruptured and leaking aneurysm. They are stated as follows:

1. Unruptured Aneurysm

Most brain aneurysms do not manifest any indications until they become quite large in size or rupture.  A large aneurysm that grows steadily may cause strain on tissues and nervous systems resulting in:

• Soreness behind and above the eye
• Weakness 
• Numbness
• A dilated pupil inside eye  
• One side paralysis of the face
• Double vision or change of vision

2. Ruptured Aneurysm

In the event of rupturing of an aneurysm, the victim typically experiences an abrupt and awfully severe headache, and they may cause:

• Double vision
• Vomiting 
• Nausea 
• Seizures 
• Sensitivity to light 
• Stiff neck
• Short-term or prolonged loss of consciousness

3. Leaking Aneurysm

Sometimes, an aneurysm may leak, causing a little blood to seep out within the brain, which is also known as a sentinel bleed. A severe headache may be an alert sign of an aneurysm which develops a leakage a few days or weeks before a rupture takes place.  So, an intense headache combined with any other indications stated above requires quick medical intervention.   

After going through the symptoms of cerebral aneurysm, let us take a look at its causes.

Although the real cause of brain aneurysm or intracranial aneurysm is yet not certain, medical researchers and physicians believe the following factors can affect blood vessels:

• Blood infection 
• Hypertension/High blood pressure
• Smoking 
• Use of cocaine and amphetamine 
• Traumatic brain injury (caused by accident)
• Build-up of fat on the walls of blood vessel  

Apart from identifying the causes, one should also determine the potential risk factors of a brain aneurysm, in order to take the necessary preventive and precautionary measures.

In certain incidences, the following inherited risk factors may lead to cerebral aneurysm: 

• Polycystic kidney ailment 
• Hereditary connective tissue ailments that make artery walls thinner
• Inborn arteriovenous malformation

Some other risk factors that cause the aneurysm to develop in due course of time include:

• Untreated hypertension
• Drug abuse, particularly addiction to amphetamines or cocaine, as it increases blood pressure
• Cigarette smoking
• Intravenous drug abuse leads to mycotic aneurysms
• People aged over 40

Rarely, some other risk factors include:

• Brain tumour
• Head trauma 
• Arterial wall infection 

Also, people with diabetes or high cholesterol are vulnerable to a fusiform aneurysm.

All aneurysms do not rupture.  However, the location, size, shape, and growth in the course of follow-up evaluation often increase the risk of an aneurysm rupturing. Moreover, certain medical conditions also impact the rupture of an aneurysm: 

These risk factors include:

• Size

The largest forms of aneurysm are more prone to rupture in an individual who did not experience any symptoms. 

• Location

Aneurysms on the anterior and posterior connecting arteries found in the frontal and rear sides of the brain are more likely to rupture than those found in other parts of the brain.

• Growth

Aneurysms that develop steadily over time have an increased chance of rupturing even when they remain small.

• Smoking

Smoking has a deep connection with the development as well as the rupture of brain aneurysms. Smoking may also multiply the number of aneurysms in the brain.

• Family History

A history in a family related to aneurysm rupture demonstrates a great risk of aneurysms forming and rupturing in other family members.

Now let us look at how brain aneurysm is diagnosed.

Often brain aneurysms go unidentified until they rupture. So, if you experience any of the above symptoms associated with a ruptured aneurysm, you should visit a doctor for the necessary examination. To check if blood leaks within the space between the brain and skull, the diagnostic stages and procedures may involve the following.

1. Assessment of Risk

Your doctor performs a risk assessment if you are diagnosed with an unruptured brain aneurysm. The assessment will help figure out if surgery is essential.

The risk assessment is done on the basis of certain factors:

• Age: Research has established that the risks related to surgery in older people often overshadow the possible benefits of extending one’s normal lifespan. 
• Size: Surgery becomes essential when aneurysms become larger than 7mm. 
• Location: Brain aneurysms that develop on larger arteries are more prone to rupture.
• Health conditions: Your current health condition may exhibit an increased risk of surgery.

After analysis of the above factors, the surgical team will inform you if the benefits of getting a surgery outweigh the possible risks.

2. Active Observation

If the doctor finds that there is a potentially low risk of rupture, a plan of active observation is generally taken into consideration. In other words, you would not need surgery immediately, but you will be under regular check-ups, enabling the physician to monitor the changes carefully. Also, you may be given medicines to lower your blood pressure.  The doctor will also suggest you change your lifestyle, which can support you by lowering the chance of a rupture, for example, having foods with low saturated fat, quitting smoking, losing weight etc.

Some diagnostic tests are discussed below.

• Computed Tomography (CT)

CT scan is the foremost test process a physician will undergo to determine if there has been a blood leakage inside the brain. CT uses X-rays in order to generate cross-sectional images of both the brain as well as the skull. The CTA generates a thorough and sharp image of blood flow in the brain arteries while showing the size, shape and location of the leaking unruptured or ruptured aneurysm. Sometimes, a contrast material may be used to make the image clearer. 

• Cerebrospinal Fluid Test

Suppose you exhibit symptoms of rupturing an aneurysm. However, if it is not detected in a CT scan with evidence of haemorrhage, your doctor may consider having a cerebrospinal fluid test to diagnose it. This test helps examine the composition of the fluid that cushions the spinal cord. Generally, a doctor draws the cerebrospinal fluid by means of inserting a needle through a lumbar vertebra, a procedure known as lumbar puncture.

• Magnetic Resonance Imaging (MRI)

This imaging procedure adopts radio waves with magnetic fields to get a full image of your brain, either 2D or 3D, as necessary. This will help in diagnosing if bleeding has occurred in your brain. In addition, producing a detailed image of MR scan can help notice the shape, growth and location of an aneurysm. 

• Cerebral Angiography

This imaging procedure helps identify blockages in the brain's blood vessels and surrounding area. It also helps figure out the reason for bleeding and locating the exact zone, shape and size of an aneurysm. By using a catheter, the physician may inject some contrast dye into the cerebral blood vessels in order to get a comprehensive and clearer image of an affected aneurysm.

Surgery can help in the treatment of brain aneurysms for those who carry a risk of an aneurysm. However, brain surgery is risky and can lead to serious conditions like damage to the brain, stroke, and even death. Therefore, your doctor will go for surgery only if there is a great likelihood of a burst. 

1. Neurosurgical Clipping

As a part of this surgical procedure, a neurosurgeon uses tools to penetrate the cranium or skull and seal off the aneurysm. This operation prevents the swelling from bursting or growing further in future. In case the aneurysm is larger in size and if it is multifaceted, the surgeon may choose to clip off the ballooning blood vessel. It prevents the aneurysm from rupturing which threatens the patient’s life.

To deal with such a complex case, a neurosurgeon follows a technique known as bypass. This involves diverting the blood flow nearby the clamped part by the removal of an artery from a different place in the body, generally the leg.

2. Endovascular Coiling

A neurosurgeon performs endovascular coiling procedures under general anaesthesia. During the surgery, the doctor inserts a tiny tube known as a catheter into a blood vessel in the groin or leg. Then the tube is carried via the network of arteries upward to reach your head and, thereafter, finally into the aneurysm. After this, the doctor uses thin platinum coils guided through the catheter into the aneurysm.

The objective is to fill up the aneurysm with coils so that blood cannot pass into it. Thus the doctor seals the aneurysm from the main blood vessel while preventing it from growing further or rupturing.

3. Emergency Treatment

Suppose you are in need of emergency treatment due to rupturing of a brain aneurysm. In that case, the doctor will prescribe you a medicine called nimodipine to lessen the risk of disruption of blood supply to your brain and causing cerebral ischaemia.

4. Rehabilitative Therapy

Individuals who have experienced a subarachnoid haemorrhage may require physical, occupational and speech therapy to recoup their lost normal functionality and deal with any sort of permanent disability. 

Around 25% of people with ruptured cerebral aneurysm do not survive more than 24 hours. A quarter of those who survive often passes away due to different health complexities within 6 months.  Individuals who develop subarachnoid haemorrhage may have long-term neurological damage.

If you are diagnosed with a brain aneurysm, you can manage the likelihood of its growth, formation of a new aneurysm, and rupture. Make sure to maintain a healthy lifestyle by following certain steps as mentioned below:  

• Intake balanced diet 
• Exercise on a regular basis 
• Focus on low-impact workouts and avoid high-impact ones
• Quit smoking
• Avoid consuming alcohol and use of drugs like cocaine 
• Keep your blood pressure under control by taking the necessary medications

A brain aneurysm is basically a bulging that occurs in an artery in the brain. The bulge can rupture or leak, resulting in brain haemorrhage and stroke. Although many aneurysms do not rupture, if you experience the above symptoms, make sure to consult a doctor right away.