Brain aneurysm 


An X-ray angiogram of a brain aneurysm   

An aneurysm is a bulge in a blood vessel caused by a weakness in the blood vessel wall, usually where it branches.

As blood passes through the weakened blood vessel, the blood pressure causes a small area to bulge outwards like a balloon.

Aneurysms can develop in any blood vessel anywhere in the body, but the two most common places for them to form are in the abdominal aorta (the artery that transports blood away from the heart to the rest of the body) and the brain.

This topic is about brain aneurysms. Read the separate topic on abdominal aortic aneurysm.

About brain aneurysms

The medical term for an aneurysm that develops inside the brain is an intracranial or cerebral aneurysm.

Most brain aneurysms will only cause noticeable symptoms if they burst (rupture).

This will then lead to an extremely serious condition known as a subarachnoid haemorrhage, where bleeding caused by the ruptured aneurysm can cause extensive brain damage and symptoms such as:

  • a sudden agonising headache – it has been described as a ‘thunderclap headache’, similar to a sudden hit on the head, resulting in a blinding pain unlike anything experienced before
  • stiff neck
  • sickness and vomiting
  • pain on looking at light

About three in five people who have a subarachnoid haemorrhage will die within two weeks and half of those who survive are left with severe brain damage and disability.

Read more about the symptoms of a brain aneurysm.

A ruptured brain aneurysm is a medical emergency. If you suspect that you or someone in your care has had a ruptured brain aneurysm, call 999 immediately and ask for an ambulance.

How brain aneurysms are treated

If a brain aneurysm is detected before it ruptures, treatment may be recommended to prevent it from rupturing in future. Most aneurysms, however, will not rupture so treatment is only carried out if the risk of a rupture is particularly high.

Factors that affect whether treatment is recommended include your age, the size and position of the aneurysm, your family medical history and any other health conditions you have.

If treatment is recommended, this will usually involve either filling the aneurysm with tiny metal coils, or an open operation to seal it shut with a tiny metal clip.

If your risk of a rupture is low, you will have regular check-ups to monitor your aneurysm. You may also be given medication to reduce your blood pressure and advice about ways you can reduce your chances of a rupture, such as stopping smoking if you smoke.

The same techniques used to prevent ruptures are also used to treat brain aneurysms that have already ruptured.

Read more about diagnosing brain aneurysms and treating brain aneurysms.

Why brain aneurysms develop

Exactly what causes the wall of affected blood vessels to weaken is still unclear, although risk factors have been identified, including: 

In some cases, an aneurysm may develop because there was a weakness in the walls of the blood vessels at birth.

Read more about the causes of brain aneurysms.

Who is affected

It's difficult to estimate exactly how many people are affected by brain aneurysms because in most cases they cause no symptoms and pass undetected. Some experts believe it could be as high as one in 20 people, while others think the figure is much lower at around one in a 100 people.

The number of aneurysms that actually rupture is much smaller. Only around one in 12,500 people will have a ruptured brain aneurysm in any given year in England.

Brain aneurysms can develop in anyone at any age, but are more common in people over 40 years of age and women tend to be affected more commonly than men.

Preventing brain aneurysms

The best way to prevent getting an aneurysm, or reduce the risk of an aneurysm growing bigger and possibly rupturing, is to avoid activities that could damage your blood vessels, such as:

  • smoking
  • eating a high-fat diet
  • not exercising regularly
  • being overweight or obese

Read more about preventing aneurysms.

Page last reviewed: 21/08/2013

Next review due: 21/08/2015


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The 8 comments posted are personal views. Any information they give has not been checked and may not be accurate.

Kaz B 196 said on 17 October 2014

Hi. My story started on 27th September last year. I suffered with high blood pressure and was terrible with taking my medication. On this day my husband got up really early for work, which I don't remember. Because he had started early he came home at lunchtime. He came in and all he could hear was me moaning upstairs. He came up and found me in bed, I had messed myself and he could get no sense out of me. An ambulance was called and I was blue lighted to our local hospital and immediately sedated. That night I was taken to Southampton hospital and had 2 coils put in the back of my neck. My family were then told I had a brain aneurysm. I was in intensive care for 2 weeks with a 1 in 4 chance of survival. I am so lucky to still be here with no complications apart from my eyesight. I couldn't see when I first came home but am back driving now and the blood is dispersing from behind my eyes. I will forever be grateful to my friends, family and the amazing staff for saving my life and still being there for me over a year later. I have read the comments on here and really feel for people that are suffering still with headaches etc and just want to put out there how important it is to take your medication every day. I know live my life to the full. If anyone who suffered the same want to get in contact it would be lovely to chat and help if I can

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Sha22 said on 24 April 2014

I recently had a head scan,and today have been told I have a Brain Aneurysm,now I'm worried!

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das57uk said on 09 April 2014

My story started on December 13th 2013 while checking my emails I felt something go pop in my head followed by the worst headache I have ever had. I went to bed the next day my headaches were no better. I went to my GP at 6pm as soon as I explained to him what had happened the day before he immediately phoned? for an ambulance and said to me that he thought I have suffered a subarachnoid haemorrhage (SAH). well a few hours later I was transferred from my local hospitals A@E to a specialist stroke unit some way fom my home I had no mobile phone with me so could not speak to my wife or any one else, the CAT scan I had confirmed I had suffered a major bleed in my brain and I had to undergo surgery to fix the bleed.
At this point from my point of view I did not know if I would live or die and still could not talk to my wife. I had surgery and now have four titanium coils in my brain, the surgeon told me the next day I had been very lucky to survive and without any notable loss of function to my limbs right or left side. Made me one of 4% of survivors that has this out come. Since then because I have not been affected in the way people expect people take the attitude well yes you had a bad experience but you are ok now. Far from it now I have permanent forgetfulness loss of short term memory, very intense headaches most of the time, loss of balance and dizziness, unable to make decisions, feelings of panic when I am around crowds of people like shopping, feelings of sadness and hopelessness and other problems. None of these can been seen.
At a glance even the people closest to me treat me like I am now better and cured
This is the most frustrating thing of all

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allanrj said on 07 September 2013

after 3 years of severe headaches which my gp insisted were caused by the small amount of athritus in the top of my spine. I had an aneurism which bled in july 2009 and was rushed into hospital thankfully it stopped and after drug treatment I had an operation to coil and fit a stent to close it off . it was in part of the brain called the bassall ganglion the consultant, who was first class said it was safe, ever since I have had headaches constantly and balance problems now the headaches and pain are getting worse and now exactly the same as before the first bleed my doctor refused when I asked to be refered to hospital, and said because ive had one doesn't mean theres another looks like i'll have to wait till I collapse again

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MariaFotina said on 17 July 2013

At the start of march I came come to my mum fitting on the kitchen floor. I called 999 and asked for an ambulance panicking on the phone. The ambulance took an hour to come when we live 10 minutes away from the hospital. My mum was took to a room in a&e. They did some scans on her but she was acting weird on the bed, saying words thay dnot exist and moving around the bed as if she was irritated. It then took 6 hours for my mum to get a brain scan. I went home for some sleep when I got a phonecall in the morning saying my mum had got rushed to addenbrookes hospital because they had found bleeding in the brain. When I got to addenbrookes they explained that my mum have had a ruptured aneurysm and they had operated immediately to coil the aneurysm. She was in critical care for 4 weeks and I got told the risks. Paralysis, brain damage, stroke or death. When my mum got taken out of critical care she came home after another two weeks of being at the local hospital. It has been 3 and a half months since my mums aneurysm had ruptured and she is now living at home again as her life alot more happier as before. She is healthy and has quit smoking since coming out of hospital. The doctors at addenbrookes were amazed how quickly and well she recoverd. I am now a little paranoid incase I have one abit runs through the family. I do get frequent headaches and I wonder if I can get checked and diagnosed if I do have a aneurysm.

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Ger209 said on 12 July 2013

Late last year I was diagnosed as having an aneurysm after enduring very painful headaches for 2 years my doctor finally sent me for an MRI scan.
I have a 14mm Fusiform aneurysm on a 2mm artery. After having a 5 hour cold coiling operation on the 21st Dec 2012 I'm still here.
I'm 39 years old, I don't smoke, I don't drink and I've lived a generally healthy life.
Why the hell did I get one.
My whole life has changed, I daren't do anything too physical for fear of what might happen, I still have the bad constant headache why stays with me 24/7.
At night I go through my usual routine of taking about 30 mins to lie down, if I don't, I feel like my head is going to explode. Every night I'm frightened to go to sleep in case I don't wake up. I live in constant fear of the damn thing rupturing, I've been told by specialists that due to the location of my aneurysm, if it does pop I wont know anything about it because of where it is, it's located near the part of the brain that controls basic functions, breathing , heart rate etc, etc.
I've become very irritable and short tempered, my poor wife is having a bad time of it, I try so hard to not moan about stuff but I really do struggle. I've gone from being a really easy going, happy go lucky type of guy to a miserable, tired, snappy and frightened little boy.
I hate it.

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shep1982 said on 31 March 2013

My mum got diagnosed with one in 2005 and they couldnt treat it and 9th of feb this year it ruptured and she died she was only 56 love her loads xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

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margaret1498 said on 02 January 2012

I believe aneurysms are due to a weakness in the arteries and run in families. My brother had a bleed (ruptured aneurysm) at age 26 he was fit active not overweight or a smoker. At age 42 I had a ruptured aneurysm and spent months in the National Hospital. I had a slight stroke and paralysis down the left side. We were both very lucky and both survived without problem. Thereafter at age 54 I had 3 further aneurysms one of which was about to rupture and underwent surgery at the National where 2 were clipped off but they could not deal with the third due to where it was located. I had a further slight stroke but luckily again recovered and returned to normal life. I was then told by the surgeon that they could not operate on the remaining aneurysm as due to my age they could not put me through the trauma of surgery again and the possibility of a further stroke or suchlike.
I have always been very grateful to the National for the
treatment I received and what they did for me in the past but I continue to have to live with an aneurysm that I have now had since 2001 not knowing if or when it might see fit to rupture and wonder if I will be as lucky as I have been in the past. My brother never had any further problems other than his one aneurysm at age 26 years. I believe it is in the genes as my mother and many of her family were epileptic and I feel certain it has some sort of bearing on myself and my brother's problems.

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