"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 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.
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:
CT scan Computed Tomography A CT scan uses a large machine shaped like a large donut to take x-rays from many angles. A computer then takes the x-rays and creates many detailed pictures of the inside of your body. Each... read more or MRI Magnetic Resonance Imaging (MRI) MRI is a test that uses a machine with a powerful magnet to make pictures of the inside of your body. A computer records changes in the magnetic field around your body. The computer then uses... read more
Sometimes angiography Angiography "Angio" is a medical term for blood vessels, and "graphy" has to do with pictures (think photography). So angiography is taking pictures of your blood vessels. It takes the pictures using x-rays... read more to get detailed pictures of the blood vessels inside your brain
Sometimes, a spinal tap Spinal Tap Spinal fluid is a liquid that surrounds your brain and spinal cord. Spinal fluid helps cushion your brain if you hit your head or fall. Spinal fluid moves freely around your brain and spinal... read more (when doctors take some fluid with a long, thin needle from your spine to check for blood)
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 Stroke A stroke is a sudden brain problem that happens when a blood vessel in your brain either gets blocked or breaks open and bleeds. Part of your brain stops getting blood. Brain tissue that doesn't... read more (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