Patient education: Subarachnoid hemorrhage (The Basics)

What is a subarachnoid hemorrhage? — 

This is a type of stroke that causes bleeding around the brain. "Hemorrhage" means bleeding.

For a subarachnoid hemorrhage, the bleeding happens in a part of the head called the "subarachnoid space." This is the area between the brain and the thin layer of tissue that covers it (figure 1).

A bad fall or injury to the head can cause subarachnoid hemorrhage. Another common cause is a bulging blood vessel that bursts. This is called a "ruptured aneurysm."

A subarachnoid hemorrhage is life-threatening, especially when it is caused by a ruptured aneurysm. Many people who have a subarachnoid hemorrhage die from it.

What are the symptoms of a subarachnoid hemorrhage? — 

The main symptom is sudden and very painful headache. It can feel like the worst headache you ever had.

Other symptoms include:

●Passing out

●Having a seizure

●Nausea or vomiting

●Stiff neck

●Being bothered by bright light

Is there a test for subarachnoid hemorrhage? — 

Yes. Your doctor might order 1 or more of these tests:

●CT scan of the head – This is an imaging test that takes pictures of the inside of the head. If the bleeding around the brain happened in the last several hours, a CT scan will likely show it.

●Lumbar puncture (sometimes called a "spinal tap") – A doctor puts a needle into the lower back and takes out a small sample of spinal fluid. This is the fluid in the subarachnoid space that surrounds the brain and spinal cord. If it has more red blood cells than usual, you could have a subarachnoid hemorrhage. This test is done if the CT scan does not show bleeding, but your doctor still thinks you might have a subarachnoid hemorrhage.

●Other imaging tests – If the CT scan or lumbar puncture shows a subarachnoid hemorrhage, your doctor might do other tests to see if the cause is a ruptured aneurysm. These tests include:

•CT angiography ("CTA") or magnetic resonance angiography ("MRA") – These use special types of CT and MRI scans to create pictures of the blood vessels in the brain. Doctors use a dye injection in CTA, and sometimes in MRA. The dye is a chemical that makes blood vessels show up on the test more clearly.

•Catheter angiography – The doctor puts a thin tube into a large artery in the leg. Then, they move the tube into the large blood vessels that carry blood to the head. The doctor injects a dye into the tube that shows up on an X-ray. The dye can show an aneurysm or other problems with the blood vessels in the brain.

How is a subarachnoid hemorrhage treated? — 

Most people who have a subarachnoid hemorrhage go to the intensive care unit ("ICU") for treatment. There, the doctor might:

●Give medicines and other treatments to reduce brain damage caused by the bleeding

●Give medicines to lower blood pressure if it is too high

●Stop "anticoagulant" and "antiplatelet" medicines – These include aspirin, warfarin (brand name: Jantoven), apixaban (brand name: Eliquis), and similar medicines used to prevent or treat blood clots. If you take any of these, your doctor might give you treatments to help your blood clot. This can help stop bleeding.

●Do tests to figure out the cause of the bleeding

●Watch the pressure in your brain to make sure it does not get too high

If an aneurysm caused the subarachnoid hemorrhage, doctors must do surgery or another procedure to keep the bleeding from happening again. Depending on the size and location of the aneurysm, they might:

●Put tiny coils in the aneurysm to seal it off. They might also put in a tiny mesh tube called a "stent" to keep blood flowing the right way. These are done during a catheter angiography procedure.

●Do surgery to put a small clip on the aneurysm

After a subarachnoid hemorrhage, most people stay in the ICU for a few days, weeks, or sometimes longer. Doctors and nurses watch for problems such as:

●Vasospasm – This is when the arteries in the brain spasm, causing them to suddenly get narrower. This can happen in the first few days and weeks after a subarachnoid hemorrhage. It can lead to a stroke.

●Electrolytes that are out of balance – Electrolytes are chemicals in the body that must be present in the right amounts for your body to work correctly.

●Irregular heartbeat

●Seizures

●Blood clots in the legs

●Lung infections

What will my life be like? — 

A subarachnoid hemorrhage is very serious. Many people die from this type of stroke. Many people who survive have long-lasting health problems afterward.

People who have severe subarachnoid hemorrhages can have certain health problems later, such as:

●Memory problems

●Mood changes or problems with emotions

●Thinking problems

●Trouble speaking, walking, or doing other activities

●Seizures

For some people, these problems can be disabling. Other people might not have these problems, or have them only mildly.

More on this topic

Patient education: Stroke (The Basics)
Patient education: Intracerebral hemorrhage (The Basics)
Patient education: Brain aneurysm (The Basics)

Patient education: Hemorrhagic stroke treatment (Beyond the Basics)
Patient education: Stroke symptoms and diagnosis (Beyond the Basics)