Subarachnoid Hemorrhage

Subarachnoid hemorrhage is a life-threatening condition that requires emergency medical care. It’s a type of stroke that occurs when a blood vessel ruptures. Blood quickly fills the area immediately surrounding the brain and spinal cord. This space contains the cerebrospinal fluid. The fluid cushions and bathes the brain and spinal cord.

The hemorrhage may increase the pressure around the brain. It can interfere with the brain's ability to function.

Subarachnoid hemorrhage may be caused by:

  • Head trauma
  • Rupture of cerebral aneurysms and other blood vessel deformities
  • Bleeding disorders
  • Drug use, especially with cocaine and amphetamines
  • Brain tumors

Risk Factors

Factors that may increase your chance of developing subarachnoid hemorrhage include:

  • Past history of aneurysms
  • High blood pressure, which increases the risk of aneurysm rupture
  • Smoking
  • Heavy alcohol consumption
  • Cocaine use
  • Disorders associated with weakened blood vessels, including polycystic kidney disease, fibromuscular dysplasia or connective tissue disorders
  • Estrogen deficiency
  • Family history of aneurysms

Subarachnoid Hemorrhage Symptoms

Symptoms may include:

  • A very sudden, severe headache
  • Brief loss of consciousness
  • Seizures
  • Nausea and vomiting
  • Weakness on one side of your body
  • Unexplained numbness or tingling
  • Slurred speech or other speech disturbance
  • Visions problems, such as double vision, blind spots or temporary vision loss on one side
  • Stiff neck or shoulder pain
  • Confusion

If you have these symptoms, call for emergency medical services right away. Early care can decrease the amount of damage to brain.

Diagnosis & Treatment

Your doctor will conduct a physical exam and ask about your symptoms and medical history. Your cerebrospinal fluid may need to be tested. This can be done with a lumbar puncture.

Your doctor may also need to take images of your internal body structures. This can be done with:

  • CT scan of the head
  • Angiogram
  • CT angiogram
  • MRI scan 

Subarachnoid hemorrhage requires initial treatment in the intensive care unit. Treatment aims to stop the bleeding, limit damage to the brain and reduce the risk of it occurring again. If bleeding results from a cerebral aneurysm, your doctor will usually attempt to stop it using various techniques. Patients receive medication to ensure proper blood flow to the rest of the brain. You will require bed rest to prevent additional bleeding and a vigorous rehabilitation program.


Aneurysms present since birth cannot be prevented. Because they are so rare, doctors do not advise screening for them. If an unruptured aneurysm is discovered by chance in a young person, the doctor may do surgery.

Avoiding smoking and controlling blood pressure can reduce the risk of a rupture if an aneurysm exists. Wearing a seatbelt and using a helmet can also reduce the risk of subarachnoid hemorrhage from head trauma.


Content was created using EBSCO’s Health Library. Edits to original content made by Rector and Visitors of the University of Virginia. This information is not a substitute for professional medical advice.