Subarachnoid Hemorrhage (SAH): what it looks like and what to do

Subarachnoid hemorrhage is bleeding into the space around the brain. It often comes on suddenly and feels very different from a normal headache. If you or someone near you has a sudden, severe headache — a "thunderclap" pain — treat it as an emergency.

Signs, causes, and why speed matters

Common signs: the worst headache of your life, neck stiffness, nausea or vomiting, confusion, sensitivity to light, weak limbs, or brief loss of consciousness. Sometimes people have only a bad headache and no other signs, so don't ignore it.

Most non-traumatic SAH cases happen when a small ballooning of an artery (an aneurysm) tears. Head injury can also cause SAH. After the first bleed, the real risks are rebleeding and delayed blood vessel spasm that can cause a stroke.

Immediate steps to take

Call emergency services right away. While you wait, keep the person calm and still. If they're unconscious, check breathing and start CPR if needed. Do not give aspirin or other blood thinners. Don't give drinks or medications by mouth if the person is drowsy or vomiting.

When the patient reaches the hospital, doctors act fast to find the bleed and stop it. Quick diagnosis and treatment lower the chance of rebleed and other complications.

How doctors confirm SAH: a head CT scan is the first test and usually finds blood right away. If the CT is negative but suspicion stays high, a lumbar puncture (spinal tap) can pick up blood products not seen on CT. Angiography — either CT angiogram or catheter angiogram — finds the source like an aneurysm.

Treatment focuses on securing the bleeding source, preventing rebleed, and managing complications. If an aneurysm caused the bleed, options include endovascular coiling (less invasive) or surgical clipping. Doctors also manage blood pressure, reverse any blood-thinning medicines, and give medication to reduce the risk of vessel spasm. That spasm risk is highest about 3–14 days after the bleed, with a peak around day 7–10.

Complications can include vasospasm (leading to delayed ischemic injury), hydrocephalus (fluid buildup), and seizures. Many people need ICU monitoring, sometimes a drain for excess fluid, and rehabilitation afterward for weakness or speech problems.

What about recovery and prevention? Recovery varies a lot — some people bounce back quickly, others need weeks to months of rehab. To lower risk, treat high blood pressure, avoid smoking, and follow up if an aneurysm was found. If you have symptoms that fit SAH, don’t wait — fast care saves brain function and lives.