Thunderclap Headache & SAH

Why this matters

The patient is 42. Light hurts their eyes, and they say they get migraines. Some crews give ondansetron and dim the lights. A thunderclap headache reaches its worst within seconds to a minute. Treat that sudden worst headache as a bleed around the brain until proven otherwise. The hospital name for that bleed is subarachnoid hemorrhage. First, check glucose and keep the scene short. Transport for a CT scan. A normal GCS does not clear an aneurysm. A sentinel leak can look like a migraine, get sent home, and then rebleed. Do not clear this because the neurologic exam looks normal.

Key points

Ask the onset story first. Ask whether it peaked in seconds or built over hours. Ask if it is the worst of their life, and whether it started with exertion, sex, or straining. Check neck stiffness, vomiting, a seizure at the start, and light sensitivity.
Check glucose. A one-sided deficit or a seizure still follows a stroke pathway. See the stroke-mimics lesson.
Keep them still. Raise the head of the bed if your protocol says so. Do not wrestle for an IV in a screaming, light-sensitive patient if you already have access.

Clinical sequence

Protect the airway, breathing, and circulation. Check glucose. Do a quick neurologic look: pupils, speech, arms, and neck.
If this is thunderclap, the worst of their life, a stiff neck, or a new deficit, keep the scene short. Go to a hospital that can do a CT scan and manage an aneurysm under your stroke or neurosurgery plan. Your protocol owns the routing. Any scanner is not automatically the right door.
Treat pain and nausea per protocol without delaying the exit. Do not spend 25 minutes on a migraine workup on scene.
If they seize or the GCS falls, protect the airway and make the destination even more urgent.

Teaching points

Thunderclap means the peak is in seconds. It is not a headache that built all afternoon.
A normal neurologic exam does not clear a subarachnoid hemorrhage. A sentinel headache can look like a migraine.
Neck stiffness plus fever also puts meningitis on the list. That patient still goes to an emergency department, not home. See the meningitis lesson.
You cannot clear this bleed on scene. Missing a sentinel bleed can send them home. Transporting a possible bleed is the smaller error.

Verbalize

This is a thunderclap headache, the worst of their life. I am not treating it as a simple migraine.
Say the glucose you measured.
The destination can do a CT scan and treat. Our protocol owns which door.
Scene time stays short.

Common errors

Do not give a migraine medication bundle and accept a refusal because the GCS is 15.
Do not spend 20 minutes on scene with the lights down to help the light sensitivity.
Do not skip glucose on an “obvious migraine.”

Practice

One-minute check

A 42-year-old has 10-out-of-10 pain that peaked in seconds while lifting, a stiff neck, and a GCS of 15. They want to stay in the dark. Say the radio sentence and the destination. What finding is not required before you take them?

Sources & Further Study

Named guidelines for further study. They are not clinical orders and do not replace your protocol or medical direction.

NASEMSO National Model EMS Clinical Guidelines (2022) — U.S. EMS model language; your protocol still decides care
2023 AHA/ASA Aneurysmal Subarachnoid Hemorrhage Guideline — sudden severe headache is the classic presentation — urgent CT-capable evaluation
2026 AHA/ASA Acute Ischemic Stroke Guideline — EMS: glucose, short scene, right stroke hospital — severe headache with deficit still activates

Education only. Apply learning within your protocols and medical direction. This is not clinical care guidance.

← Adrenal Crisis in the Field Field Death Notification →

Why this matters

Clinical sequence

Teaching points

Common errors

Practice

One-minute check

Sources & Further Study

Check Your Understanding