by EBSCO Medical Review Board


A subarachnoid hemorrhage (SAH) is bleeding in the space that surrounds the brain. This can raise pressure around the brain. SAH can be deadly.


SAH may be caused by:

Risk Factors

SAH is more common in people who are aged 50 years and older. Other things that may raise the risk are:


Problems may be:

  • Sudden, severe headache
  • Nausea and vomiting
  • Stiff neck
  • Light sensitivity
  • Loss of consciousness
  • Seizures


The doctor will ask about your symptoms and health history. A physical exam will be done. This may be enough to suspect the diagnosis.

Pictures may be taken of the brain and the structures around it. This can be done with:

The fluid in the spine may need to be tested. This can be done with a lumbar puncture.

CT Scan of the Head
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Emergency care is needed right away. The goals of treatment are to:

  • Stop the bleeding
  • Limit harm to the brain
  • Reduce the risk of another SAH

Options are:

  • Surgery to stop an aneurysm from bleeding
  • Medicines to help blood flow to the brain, to ease pain, and to treat other symptoms, such as seizures

Rehabilitation will be needed when a person is stable. This may include speech, physical, and occupational therapy.


SAH cannot always be prevented. To lower the risk:

  • Manage high blood pressure
  • Avoid using tobacco
  • Limit alcohol
  • Eat a healthful diet


The Brain Aneurysm Foundation 

National Stroke Association 


Brain Injury Canada 

Heart and Stroke Foundation 


Macdonald RL, Schweizer TA. Spontaneous subarachnoid haemorrhage. Lancet. 2017 Feb 11;389(10069):655-666.

Subarachnoid hemorrhage. EBSCO DynaMed website. Available at: Accessed October 5, 2020.

Revision Information

  • Reviewer: EBSCO Medical Review Board Rimas Lukas, MD
  • Review Date: 09/2020
  • Update Date: 05/25/2021