"Sub" means under. The arachnoid is a layer of tissue that covers your brain. Hemorrhage is bleeding. So a subarachnoid hemorrhage is bleeding under the arachnoid tissue layer. It's a medical emergency that can be fatal or cause long-lasting brain damage.
People who have any symptom of a subarachnoid hemorrhage should go to an emergency department immediately.
Bursts and Breaks: Causes of Hemorrhagic Stroke
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 for many years. You may have more than one aneurysm in your brain.
When an aneurysm ruptures it usually causes:
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:
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.
Doctors will usually suspect subarachnoid hemorrhage based on your symptoms. To make sure they're right, they'll do tests right away to see if your brain is bleeding and where it's bleeding:
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 and prevent an ischemic stroke (no aspirin or ibuprofen as these can cause more bleeding)
Medicine and fluids to keep your blood pressure at the right level
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