Brain Aneurysm: Causes, Symptoms and Treatments

What Is a Brain Aneurysm?

Types of aneurysms:

• Saccular – Also known as "berry" aneurysm because of its berry shape, a saccular aneurysm is the most common type of brain aneurysm. It has a "neck" that connects the aneurysm to its main artery and a larger, rounded dome area.

• Fusiform – A lesser-known type of brain aneurysm, it has an irregular shaped widening of a cerebral vessel that does not have a defined "neck" or pouch.

• Dissecting – This type of aneurysm is often caused by a traumatic injury, resulting in a tear in the artery's wall that allows blood to accumulate in between layers and develop into an aneurysm.

Ruptured Aneurysm

When an aneurysm ruptures, it causes bleeding (haemorrhagic stroke). A patient with a ruptured aneurysm will experience a sudden and intense headache, also known as a thunderclap headache—experienced as an extremely severe headache, often remarked as the worse one has ever felt.

It is a medical emergency and calls for immediate treatment. 

• A ruptured aneurysm bleeds into the space between your brain and surrounding tissues: this type of haemorrhagic stroke is called a subarachnoid haemorrhage.

Unruptured Aneurysm

It’s also important to note that 50–80% of brain aneurysms don’t rupture. They don’t cause health problems or show symptoms. Because of this, most people do not know that they have one. Patients with unruptured aneurysms are often diagnosed with it when they are being tested for other conditions.

• Treating an unruptured brain aneurysm may be appropriate in some cases and may prevent a rupture in the future. If concerned, please speak with your GP, and book a referral at Royal Prince Alfred Hospital.

Risk Factors of a Brain Aneurysm

Whilst the specific causes of a brain aneurysm is unknown, several factors can contribute to its development:

Older age

Anyone at any age can develop a brain aneurysm. But it’s more common in people over the age of 40. Women are more likely than men to develop a brain aneurysm (3:2 ratio).

Cigarette smoking

Smoking increases the growth and risk of aneurysm ruptures. It destroys the walls of the arteries and breaks down their lining. The body attempts to repair this by forming clots and plaque, weakening the arterial wall and thus forms an aneurysm. A study by Pennsylvania State University College of Medicine found that 7 in 10 aneurysm patients were smokers.

High blood pressure or hypertension

The constant higher-than-normal blood pressure may, over time, weaken one’s blood vessels within the brain and cause a section of its wall to inflame and form an aneurysm.

Drug abuse

The use of cocaine is known to increase the risk of blood vessel disorders, including aneurysm

Heavy alcohol consumption 

Excessive drinking has been linked to the development of a brain aneurysm.

Family history or certain genetic conditions

In most cases, brain aneurysms are not hereditary. But there are some cases where an individual diagnosed with a brain aneurysm will have other family members who have it too. When two or more first-degree relatives (parent, child, or sibling) are diagnosed with aneurysms, these are called familial aneurysms.

Head trauma

Trauma is a factor in fewer than 1% of patients with brain aneurysms, more commonly found in the pediatric population. A brain aneurysm can occur after even mild or seemingly trivial head trauma. It is associated with a high mortality rate of 50%.

Blood infections 

Mycotic aneurysms are a rare cause of brain aneurysms that develop due to infection caused by bacteria entering the bloodstream and settling in the blood vessel. While it’s rare, it becomes deadly when the aneurysm ruptures.

Kidney disease 

• While the reason remains unclear, research has found that patients with autosomal dominant polycystic kidney disease develop brain aneurysms.

Who Can Get a Brain Aneurysm?

Brain Aneurysms can occur in anyone and at any age. However, they are more common in adults ageing 30–60 and in women. 

Those who are at risk include: 

• People with disorders such as:

  • Inherited disorders

  • Ehlers-Danlos syndrome, autosomal dominant polycystic kidney disease, Marfan syndrome, and fibromuscular dysplasia

• Cigarette smokers

• People with hypertension

• Strong family history of brain aneurysms

• People of colour have an increased risk of ruptured aneurysms

• Cocaine users

• Excessive alcohol drinkers

What are the symptoms of a Brain Aneurysm?

• Large unruptured aneurysms can press on tissues and nerves in the brain and the eyes, which can result in pain, dilated pupils, loss of vision, diminished eye movements and double vision, or other neurological symptoms.

• An aneurysm may be pressing on the nerves if one experiences the following symptoms:

  • Dilated pupils

  • Drooping eyelids

  • Sudden blurred or double vision

  • Weakness and numbness

  • Slurred speech

  • Nausea, vomiting, dizziness

  • Stiff neck

  • Sensitivity to light

  • Stroke

• A brain aneurysm can leak a small amount of blood, causing a sudden and severe headache. This leaking is a sign that a more severe rupture may be about to occur.

• Symptoms of a ruptured aneurysm include the following:

  • Thunderclap headache (sudden, intense headache)

  • Nausea and vomiting

  • Stiff neck

  • Blurred or double vision

  • Sensitivity to light

  • Seizure

  • Drooping eyelid

  • Loss of consciousness

  • Confusion

Aneurysm and Stroke

Contrary to what most people think, aneurysm and stroke are two very different medical issues.

A stroke occurs when a clot or rupture blocks a blood vessel that carries oxygen and nutrients to the brain. When that happens, part of the brain and cells that don’t get the blood, oxygen, and nutrients dies.

There are two types of strokes. Ischemic stroke happens when a blood clot blocks an area in an arterial blood vessel in the brain. This type of stroke accounts for about 80% of strokes.

A haemorrhagic stroke, on the other hand, is caused by a ruptured brain aneurysm.

How Is a Brain Aneurysm Diagnosed?

A ruptured or leaking aneurysm is a medical emergency: if you or someone you are with has developed a sudden, extremely severe headache (thunderclap headache), seek immediate medical attention by calling 000.

You will undergo a series of tests to check if you are suffering from subarachnoid haemorrhage (bleeding into the space between the brain and surrounding tissues) or another type of stroke.

If bleeding is confirmed, the emergency team will see if it is caused by a ruptured aneurysm.

If you are experiencing symptoms apart from the thunderclap headache, see your GP and get assessed. Once you’ve completed the assessment, your GP will then arrange a series of tests to determine the underlying cause of the symptoms. 

If you show symptoms of an unruptured brain aneurysm — such as pain behind the eye, changes in vision or double vision — your GP will perform some diagnostic tests on you to check your blood vessels and locate the offending aneurysm.

These include:

• Computerised Tomography (CT). A CT uses X-rays to look at the brain tissue and its blood vessels. Contrast or dye will need to be injected during the CT scan to provide better quality images.

• Magnetic Resonance Imaging (MRI). An MRI can also look at the brain tissue and its blood vessels. These scans take more time than a CT and there is usually a small waiting list to get a scan; however, the image quality is typically better than a CT. A small number of people do not like these scans as you are required to lie still in a confined tunnel but sedation can be given prior to the scan to relax you.

• Cerebral angiogram. During this procedure, a thin tube (catheter) is introduced into a large artery in the arm or leg and guided to the neck. A contrast or dye is injected into the flow of these arteries, and X-rays are then taken to observe the flow of your brain’s blood vessels. This procedure takes about 30–60 minutes and provides the highest quality and most detailed scan. Because it is a procedure, there is usually a few hours of recovery and it is performed as a day case.

It is common to have all three types of scans if an aneurysm is found. The Computerised Tomography (CT) scan is the easiest and quickest test to have, and your GP can readily organise this if they think it is clinically appropriate. A referral can be made to our clinic if there are any concerns or if the results need to be interpreted. MRI or angiography can then be arranged following consultation. 

If you have been found to have an unruptured brain aneurysm, please get in touch with our neurovascular clinic, and we will arrange an appointment.

Treatment for a Ruptured Brain Aneurysm

There are two common treatment options for a ruptured brain aneurysm. Both are routinely performed under general anaesthetic.

• Endovascular treatment. This is a very effective and less-invasive procedure where the interventional neuroradiologist, a neurosurgeon, or a neurologist inserts a tube (catheter) into an artery on the neck or groin and guides it to the brain aneurysm. There are several different devices including stenting/coiling or stent+coiling that can be used to close the aneurysm from inside the blood vessels. Risks include bleeding or loss of blood flow to the brain (stroke). Endovascular treatment may have a slightly higher risk of the need for a repeat procedure in the future due to reopening of the aneurysm.

• Open surgery with aneurysm clipping. The neurosurgeon removes a part of the skull (craniotomy) to access the aneurysm and locates the blood vessel that feeds the aneurysm. Then a tiny, MRI-compatible titanium clip seals the opening of the aneurysm to prevent the blood flow from entering. The clip remains on the artery permanently.

  
  

Treatment for an Unruptured Brain Aneurysm

If you’re diagnosed with an unruptured brain aneurysm, you should be referred to a specialist for review.

A careful clinical assessment with brain imaging is necessary to determine your risk of aneurysm rupture.

Aneurysms, which we deem at high risk, will be recommended for expedited treatment. Since all treatment for aneurysms is associated with risk, aneurysms that are small and carry a lower risk of rupture are best monitored in the long-term and treated if they enlarge.

How to Prevent a Brain Aneurysm from Rupturing

Reduce your risk of a rupture by living a healthy and balanced lifestyle. Don’t smoke or use recreational drugs, eat a healthy diet, and exercise regularly. You should also see your doctor for annual checkups and if you have conditions that increase your risk of rupture, they should be treated.

Brain Aneurysm Survival Rate

According to the Brain Aneurysm Foundation, ruptured brain aneurysms are fatal in about 50% of cases. Of those who survive, about 66% suffer some permanent neurological deficit.

Approximately 15% of people with a ruptured aneurysm die before reaching the hospital. Most of the deaths are due to rapid and massive brain injury from the initial bleeding.

DISCLAIMER: The information provided is designed to support, not replace, the relationship that exists between a patient or site visitor and their existing healthcare professionals.

Verified by: Dr Hugh Stephen Winters

Dr Hugh Stephen Winters is a neurologist with four years of exhaustive training in interventional neuroradiology, which includes a year of Clinical and Procedural Fellowship in Interventional Neuroradiology at the Erlanger Medical Center in Tennessee.