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Subarachnoid Haemorrhage (SAH)

A subarachnoid haemorrhage (SAH) is an uncommon type of stroke caused by bleeding on the surface of the brain.

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

Subarachnoid haemorrhage - NHS website


Symptoms of an SAH diagnosis should be treated with urgency - dial 999.

  • Sudden severe headache
  • Neck stiffness
  • Visual disturbances - double vision, blurred vision, light sensitivity
  • Nausea or vomiting
  • New limb weakness
  • Slurred speech

The bleed may be categorised in hospital as either traumatic or aneurysmal and treatment will be dependent on the type of SAH.

Types of SAH


A traumatic SAH is usually caused through head injury due to a fall or road traffic accident.


An aneurysm is a weakness in the arterial wall that bulges out like a 'balloon'. It can occur at any point in a person's life for unknown causes.

Family history, high blood pressure or smoking may increase the risk.


In up to 20 percent of patients no abnormality is identified and the bleeding is thought to originate from a small vein. This is referred to as a non-aneurysmal SAH. Patients will still experience symptoms and will need to take time to recover.


Once an SAH has been diagnosed, a CT angiogram (CTA) - a CT scan with intravenous injection of X-ray dye - is performed to look for abnormalities of the intracranial blood vessels such as an aneurysm or an arteriovenous malformation.

If a CTA does not show a vascular abnormality, a cerebral angiogram (DSA) may be performed to assess the intracranial blood vessels in greater detail. This involves a catheter being inserted into an artery in the groin (femoral artery). Dye is injected into the blood vessels in the brain and digital X-ray images are taken.

Angiogram of the brain

If the CTA and DSA do not reveal an abnormality, the diagnosis of non-aneurysmal SAH may be made.


The aim of treatment is to prevent rebleeding. Treatment will depend on whether an abnormality is found or not - the team caring for you will discuss options with you and your family.

For further reading on these treatment options please visit:

Information for patients and carers


Embolisation is a minimally invasive procedure that blocks or closes a specific blood vessel. Aneurysms are embolised using specially designed platinum coils, which are used to pack the aneurysm to prevent it from bleeding. This procedure involves treating the aneurysm from inside the blood vessels and is performed in the Angiography Suite.

Surgical clipping

Aneurysms that are not suitable for coiling or other similar forms of treatment, may be treated with a surgical clip - a neurosurgical procedure where an opening is made in the skull (craniotomy) and a metal clip is placed at the base of the aneurysm.

Conservative management

This option is when the risks of any treatment far outweigh the benefits - the team caring for you will discuss this with you and your family.

Staying in hospital

You will stay in hospital until your symptoms have settled and you are well enough to return home. Length of stay varies according to the severity of the initial bleed. Most patients go home after around ten days.

A Neurovascular Nurse Practitioner (NNP) will discuss your diagnosis and progress with you and provide advice about your discharge and recovery. You will also have a telephone consultation with the NNP six to eight weeks after discharge.

Going home / recovery

You may have some symptoms when you get home, so take plenty of rest - fatigue is very common following an SAH. Pace your return to normal levels of activity.

You may suffer with ongoing headaches, which are a normal part of the recovery process and should settle with time. Simple painkillers may help.

You may find you also have some back discomfort; again, this is normal and usually resolves itself over time. If you experience worsening headaches that become severe, seek medical assistance.

For more information related to your recovery, please visit:

Your questions answered

Last reviewed:09 January 2024