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Subarachnoid Hemorrhage


The Manual's Editorial Staff

Reviewed/Revised Sep 2023
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What is a subarachnoid hemorrhage?

A subarachnoid hemorrhage is bleeding in the space that surrounds the brain. It's a medical emergency that can be fatal or cause long-lasting brain damage.

  • Subarachnoid hemorrhage happens when a blood vessel in your brain bursts

  • You get a sudden, severe headache and you may pass out

  • Doctors may do surgery to try to stop the bleeding

People who have any symptom of a subarachnoid hemorrhage should go to an emergency department immediately.

Bursts and Breaks: Causes of Hemorrhagic Stroke

When blood vessels of the brain are weak, abnormal, or under unusual pressure, a hemorrhagic stroke can occur. In hemorrhagic strokes, bleeding may occur within the brain, as an intracerebral hemorrhage. Or bleeding may occur between the inner and middle layer of tissue covering the brain (in the subarachnoid space), as a subarachnoid hemorrhage.

Bursts and Breaks: Causes of Hemorrhagic Stroke

What causes a subarachnoid hemorrhage?

A subarachnoid hemorrhage can be caused by a head injury (for example, from a car crash).

A subarachnoid hemorrhage not caused by injury is usually caused by an aneurysm bursting in your brain.

Aneurysms are bulges in a weakened area of a blood vessel's wall. Usually, you're born with these aneurysms. Sometimes aneurysms develop later from having high blood pressure High Blood Pressure Each heart beat pushes blood through your arteries. Arteries are the blood vessels that carry blood from your heart to your body. Blood pressure is the pressure of blood in your arteries. Without... read more for many years. You may have more than one aneurysm in your brain.

What are the symptoms of a subarachnoid hemorrhage?

When an aneurysm ruptures it usually causes:

  • Sudden, severe headache (sometimes called a thunderclap headache)

  • Passing out

  • Confusion

Almost half of people with a subarachnoid hemorrhage die before getting to a hospital. Some people remain in a coma or unconscious. People who wake up may be confused and sleepy and have:

  • A stiff neck

  • Vomiting and dizziness

  • Seizures

You may recover completely or be left with brain damage.

Later on, if you have more than one aneurysm, those aneurysms can burst too, giving you another hemorrhage.

How will my doctor know if I had a subarachnoid hemorrhage?

How do doctors treat a subarachnoid hemorrhage?

Doctors will treat the problems that cause your bleeding. They'll have you stay in a hospital or stroke center where you may get:

  • Bed rest with no activity

  • Medicine to relieve your headache (no aspirin or ibuprofen as these can cause more bleeding)

  • Medicine and fluids to keep your blood pressure at the right level

  • Sometimes medicine to prevent blood vessel spasm and subsequent ischemic stroke

  • Sometimes, doctors put a small metal coil in the leaking aneurysm or do surgery to close it

  • If you have more than one aneurysm, doctors will usually treat those too, so they don't bleed later

Drugs Mentioned In This Article

Generic Name Select Brand Names
Anacin Adult Low Strength, Aspergum, Aspir-Low, Aspirtab , Aspir-Trin , Bayer Advanced Aspirin, Bayer Aspirin, Bayer Aspirin Extra Strength, Bayer Aspirin Plus, Bayer Aspirin Regimen, Bayer Children's Aspirin, Bayer Extra Strength, Bayer Extra Strength Plus, Bayer Genuine Aspirin, Bayer Low Dose Aspirin Regimen, Bayer Womens Aspirin , BeneHealth Aspirin, Bufferin, Bufferin Extra Strength, Bufferin Low Dose, DURLAZA, Easprin , Ecotrin, Ecotrin Low Strength, Genacote, Halfprin, MiniPrin, St. Joseph Adult Low Strength, St. Joseph Aspirin, VAZALORE, Zero Order Release Aspirin, ZORprin
Advil, Advil Children's, Advil Children's Fever, Advil Infants', Advil Junior Strength, Advil Migraine, Caldolor, Children's Ibuprofen, ElixSure IB, Genpril , Ibren , IBU, Midol, Midol Cramps and Body Aches, Motrin, Motrin Children's, Motrin IB, Motrin Infants', Motrin Junior Strength, Motrin Migraine Pain, PediaCare Children's Pain Reliever/Fever Reducer IB, PediaCare Infants' Pain Reliever/Fever Reducer IB, Samson-8
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