Subarachnoid hemorrhage: what it looks like and what to do

A subarachnoid hemorrhage (SAH) is bleeding into the space around the brain. The most common cause is a burst brain aneurysm. It often shows up suddenly and dramatically — a severe, 'thunderclap' headache, neck stiffness, nausea, and sometimes loss of consciousness. If you see these signs, treat it like a medical emergency.

Spotting the warning signs

The fastest way to tell something is wrong is the headache. People describe it as the worst headache of their life or a blow to the head. Other common signs are vomiting, neck pain, light sensitivity, fainting, confusion, or weakness on one side. Sometimes people have a brief warning headache days or weeks before the big bleed; that can be an early leak from an aneurysm.

Immediate steps — what you can do right away

Call emergency services immediately. Keep the person still and calm, and have them lie down with head slightly elevated if possible. Do not give anything by mouth if they are drowsy or vomiting. Monitor breathing and pulse; start basic life support if they stop breathing. Tell dispatch you suspect a brain bleed — emergency teams will prioritize rapid transport and imaging.

At the hospital, doctors will usually do a CT scan first. CT finds most acute SAH quickly. If CT is unclear but suspicion remains, a lumbar puncture can show blood in the cerebrospinal fluid. CT angiography or formal cerebral angiography finds the aneurysm or other blood vessel problems.

Treatment focuses on stopping the bleeding and preventing complications. Two main ways to fix a leaking aneurysm are surgical clipping or endovascular coiling. Which is best depends on the aneurysm shape, location, and the patient’s condition. Doctors will also control blood pressure, give pain relief, and use a drug called nimodipine to cut the risk of delayed blood vessel spasm that can cause further brain damage.

Complications to watch for include rebleeding (highest risk in the first 24 hours) and vasospasm (usually days 3 to 14 after the bleed). That’s why early repair and close monitoring in an intensive care unit matter. Rehabilitation often follows: physical therapy, speech therapy, and cognitive rehab can help recovery. Many people improve, but recovery can be slow and require ongoing support.

Can SAH be prevented? You lower your risk by managing blood pressure, quitting smoking, and avoiding stimulant drugs like cocaine. If someone in your family had a brain aneurysm, a doctor might recommend screening with an imaging test.

If you suspect a subarachnoid hemorrhage, act fast. Quick emergency care saves lives and reduces long-term damage. If you want clear, practical info on tests, treatments, or recovery steps, ask your healthcare team — they can explain options for your exact situation.