Subarachnoid haemorrhage

Symptoms of a subarachnoid haemorrhage

There are usually no warning signs, but a subarachnoid haemorrhage sometimes happens during physical effort or straining, such as:

• coughing
• going to the toilet
• lifting something heavy
• having sex

The main symptoms of a subarachnoid haemorrhage include:

• a sudden agonising headache – often described as being similar to a sudden hit on the head
• a stiff neck
• feeling and being sick
• sensitivity to light (photophobia)
• blurred or double vision
• stroke-like symptoms, such as slurred speech and weakness on one side of the body
• loss of consciousness or convulsions (uncontrollable shaking)

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.

How a subarachnoid haemorrhage is treated

A person with a suspected subarachnoid haemorrhage needs a 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're likely to be transferred to a specialist neurosciences unit.

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

Causes of subarachnoid haemorrhages

The majority of subarachnoid haemorrhages are caused by a brain aneurysm bursting.

A brain aneurysm is a bulge in a blood vessel, caused by a weakness in the blood vessel wall.

It's not known exactly why brain aneurysms develop in some people.

But certain risk factors have been identified, including:

• smoking
• high blood pressure
• drinking too much alcohol

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.

Who's affected

Subarachnoid haemorrhages can happen at any age but 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.

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

• stop smoking
• moderate your alcohol intake
• take steps to prevent high blood pressure, such as:
  • regular exercise
  • eating a healthy diet
  • losing weight if you're overweight

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 the blood supply to the brain being reduced.

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

Outlook

Although the outlook for subarachnoid haemorrhage has improved in the last few decades, around half of all cases are fatal. 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
• problems sleeping

More useful links

• How to use your health services
• Subarachnoid haemorrhage