Bleeding in the brain

Introduction
Symptoms of a subarachnoid haemorrhage
Causes of subarachnoid haemorrhages
Diagnosing a subarachnoid haemorrhage
Treating subarachnoid haemorrhages
Complications of a subarachnoid haemorrhage
Recovering from subarachnoid haemorrhage
Preventing subarachnoid haemorrhage
'After my brain injury, there were suddenly men everywhere who I fancied'

A subarachnoid haemorrhage is an uncommon type of stroke caused by bleeding on the surface of the brain. It is a very serious condition and can be fatal.

Subarachnoid haemorrhages account for around 1 in every 20 strokes in the UK.

The main symptom of a subarachnoid haemorrhage is a sudden and very severe headache that is often described as a blinding pain, unlike anything experienced before.

Other symptoms can include:

a stiff neck
being sick
sensitivity to light
blurred or double vision
seizures (fits) or loss of consciousness

A subarachnoid haemorrhage is a medical emergency. Dial 999 immediately and ask for an ambulance if you, or someone in your care, has these symptoms.

Read more about the symptoms of a subarachnoid haemorrhage.

How a subarachnoid haemorrhage is treated

A person with a suspected subarachnoid haemorrhage will need to have a computerised tomography (CT) scan in hospital to check for signs of bleeding around the brain.

If a diagnosis of subarachnoid haemorrhage is confirmed or strongly suspected, you are likely to be transferred to a specialist neurosciences unit.

Medication will usually be given to help prevent short-term complications (see below) and a procedure to repair the source of the bleeding may be carried out.

What causes subarachnoid haemorrhages?

The majority of subarachnoid haemorrhages are caused by a brain aneurysm bursting. A brain aneurysm is a bulge in a blood vessel, and is caused by a weakness in the blood vessel wall.

It is not known exactly why brain aneurysms develop in some people, although certain factors that increase your risk of the condition have been identified. These include:

smoking
high blood pressure
excessive alcohol consumption

Less common causes of subarachnoid haemorrhages include having abnormally developed blood vessels and inflammation of blood vessels in the brain.

Severe head injuries often cause subarachnoid bleeding, but this is a separate problem known as a "traumatic subarachnoid haemorrhage".

Read more about the causes of subarachnoid haemorrhages.

Who is affected

Between April 2012 and April 2013, over 11,000 people were admitted to hospitals in England with a subarachnoid haemorrhage.

Subarachnoid haemorrhages can happen at any age, even children, but they are most common in people aged between 45 and 70. Slightly more women are affected than men.

Subarachnoid haemorrhages are also more common in black people compared to other ethnic groups. This could be because black people are more likely to have high blood pressure. Read more about black health issues.

Reducing your risk

It's not always possible to prevent a subarachnoid haemorrhage, but there are some things you can do to reduce your risk.

The three most effective steps you can take to reduce your chances of having a subarachnoid haemorrhage are:

stop smoking
moderate your alcohol consumption
take steps to keep your blood pressure at a healthy rate, such as taking regular exercise and losing weight if you are overweight

Read more about preventing subarachnoid haemorrhages.

Possible complications

A subarachnoid haemorrhage can cause both short and long-term complications.

Serious short-term complications can include further bleeding at the site of any aneurysm and brain damage caused by a reduction in blood supply to the brain.

Long-term complications include:

epilepsy – where a person has repeated seizures (fits)
problems with certain mental functions, such as memory, planning and concentration
changes in mood, such as depression

Read more about the complications of a subarachnoid haemorrhage.

Outlook

Although the outlook for subarachnoid haemorrhage has improved in the last few decades, around half of all cases are fatal, and people who survive can be left with long-term problems.

Recovering after a subarachnoid haemorrhage can also be a slow and frustrating process, and it's common to have problems such as extreme tiredness, headaches and problems sleeping.

Haemorrhage: To haemorrhage means to bleed or lose blood.
Blood: Blood supplies oxygen to the body and removes carbon dioxide. It is pumped around the body by the heart.
Blood vessels: Blood vessels are the tubes in which blood travels to and from parts of the body. The three main types of blood vessels are veins, arteries and capillaries.
Brain: The brain controls thought, memory and emotion. It sends messages to the body controlling movement, speech and senses.
Tissue: Body tissue is made up of groups of cells that perform a specific job, such as protecting the body against infection, producing movement or storing fat.