What Causes a Subarachnoid Hemorrhage?

A subarachnoid hemorrhage is a type of stroke usually caused by a burst blood vessel in the brain (a ruptured brain aneurysm). 

There are usually no early signs of subarachnoid hemorrhages. When symptoms occur, they may include:

• Sudden severe headache unlike anything experienced before (“the worst headache of your life”)
• Stiff neck
• Nausea 
• Vomiting
• Sensitivity to light 
• Blurred or double vision
• Stroke-like symptoms
  • Slurred speech 
  • Weakness on one side of the body
• Loss of consciousness or convulsions

A subarachnoid hemorrhage is a medical emergency. Call 911 and get to a hospital’s emergency department (do not drive yourself) immediately if you or someone you are with experiences any symptoms of subarachnoid hemorrhage.

A subarachnoid hemorrhage is diagnosed in the hospital with tests such as: 

• Computerized tomography (CT) scan to check for signs of a brain hemorrhage
• Lumbar puncture to sample cerebrospinal fluid that surrounds the brain and spinal cord to check for signs of bleeding

If the results of the CT scan or lumbar puncture confirm a subarachnoid hemorrhage, additional testing is performed to determine treatment, including:

• Computed tomography angiography (CTA) 
• Magnetic resonance angiography (MRA)  
• Angiogram

A subarachnoid hemorrhage is a medical emergency and immediate treatment is needed to help reduce the risk of brain damage.

If a subarachnoid hemorrhage is confirmed or strongly suspected, patients are usually transferred to a specialist neuroscience unit that may include neurologists, neurosurgeons, neuroradiologists, and neurointensivists. 

Treatment for a subarachnoid hemorrhage involves stopping the bleeding, which may be done by: 

• Surgery to place a small clip on the blood vessel to stop blood from leaking into the brain
• An endovascular coil placed in the artery in that is bleeding

Long-term treatment for a subarachnoid hemorrhage involves addressing risk factors for the bleeding: 

• Quit smoking
• Manage conditions such as high blood pressure (hypertension), high cholesterol, or diabetes
• Lose weight if needed/maintain a healthy body weight
• Eat a healthy, balanced diet

A subarachnoid hemorrhage can lead to complications such as:

• Rebleeding
  • The brain aneurysm bursts again 
  • High risk of permanent disability or death
  • Aneurysm repair is needed as soon as possible
• Vasospasm (also called delayed cerebral ischemia) 
  • A blood vessel spasms, causing it to narrow
  • The blood supply to the brain becomes critically low, resulting in brain damage
  • Symptoms include increased drowsiness, which can lead to a coma
  • Medications such as nimodipine (Nymalize) may be prescribed to help prevent and treat vasospasm
• Hydrocephalus
  • Build-up of fluid on the brain, which increases intracranial pressure and can lead to brain damage
  • Symptoms may include including headache, vomiting, blurry vision, and difficulty walking
  • May be treated with a lumbar puncture or a temporary tube surgically implanted into the brain to drain excess fluid
• Long-term complications
  • Epilepsy (seizures)
  • Cognitive dysfunction
    • Problems with memory 
    • Problems with tasks that require planning 
    • Problems with concentration or attention
  • Emotional problems
    • Depression
    • Anxiety
    • Post-traumatic stress disorder (PTSD)