Thunderclap Headache: What EMS Providers Need to Know

By Frances Hall

The alarms go off at 2:30 a.m. after a decadent 12 minutes of sleep. You reach over to silence your pager, succeeding only in knocking the lamp on the table to the ground. Finally, you hold it up to read the notes: 43-year-old male, severe headache. You and your partner drive over in an exhausted silence. The patient walks out to meet you, climbing into the back without assistance. Your partner starts to take vitals.

“I’m sorry I bothered y'all,” the patient begins, clutching his temple. “It’s the worst headache I’ve ever had, and I got a TBI in Iraq, so you’d better believe that I know headaches.” You remember that this phrase is relevant.

What do you do now? The differential here is rough. There are more than 100 causes of severe headaches, ranging from things that have no clinical relevance to causes that are immediate life threats.¹ The good news is that nobody is expecting you to know whether this headache is because of dehydration or because of a “third ventricle colloid cyst” and other phrases that sound like they’re from an episode of Star Trek.

Thunderclap Headache

What you do need to determine, in short order, is whether this is truly a “thunderclap headache” (TCH). This determination is crucial because, while exact numbers vary, something like one in five patients with a true TCH is having a subarachnoid hemorrhage—a bleed under the arachnoid layer of the brain lining.² And even if it isn’t a subarachnoid bleed, other causes of TCHs include a cervical artery dissection, cerebral venous thrombosis, and several other interruptions of normal blood flow to the brain a physician should address immediately.³

However, anyone who’s worked in medicine for an extended period would be reluctant to assign so much clinical significance to a patient’s rating of their own pain. The good news is no one is asking you to. For a headache to truly be a TCH it must meet the following criteria:

1. Pain lasting longer than five minutes
2. Abrupt onset
3. Reaching maximum intensity in a minute or less
4. Not readily explained by something else, such as head trauma⁴

If your patient regularly has this kind of headache or has had several this week already, their pain isn’t harmless, but it’s not likely to be a TCH.²

The bad news is, subarachnoid hemorrhage is an unusual and insidious disorder in which a patient who is having an entirely normal conversation with you in an ambulance with perfectly normal vitals could be dead or permanently disabled in an hour. We don’t have any CTs lying around in the back of the ambulance to check. Also, these bleeds can occur spontaneously, without any history of injury or even exertion, so a lack of trauma tells you nothing.⁵

The good news is that a TCH is both very distinctive and is the most common symptom of a subarachnoid hemorrhage. A patient with this kind of headache as well as any neurological symptoms, such as altered mental status, unilateral vision changes, vomiting, or hemiplegic seizures, is even more likely to have a bleed.^6,7 But in half of subarachnoid hemorrhage cases a TCH is the only symptom the patient will complain of.

Subarachnoid hemorrhage is a grim diagnosis. Ten percent of patients will die before ever reaching the hospital; 35% will die within a year of their event. Even for the survivors, 25% will never quite be the same healthy, independent person they were before.⁸

But “grim diagnosis” is just another way of saying “special opportunity for EMS.” That means that if you recognize this otherwise routine complaint as the harbinger of doom it is, you give your patient every opportunity not only to survive but to continue their life as someone who can burn a sheet of cookies or knit dozens of cat sweaters and deliberately choose to ignore their son-in-law’s birthday despite remembering the date clearly.

Asking the Right Questions

“So, can I just stay home and take some Motrin?” the patient is asking now.

There are a few questions EMS providers should ask when a TCH is present and a subarachnoid hemorrhage is suspected. The patient’s answers can help you know how to proceed.

• Did this headache begin suddenly, or did it get worse little by little? “Hit me like a ton of bricks.”
• How long did it take for the pain to reach its maximum? Five minutes? An hour? “Right away.”
• How long have you had this headache? “Thirty minutes.”
• Have you experienced headaches like this sometimes or ever before? “No. Never.”

You package your patient and call the hospital immediately. When you arrive, the neurologist asks you why he’s here right now and you stumble through your report.

The neurologist lets out a slow sigh and buries his face in his hands as you explain, but you can tell what he really meant to say was, “Great catch.”

You check the outcome later and let out a slow sigh of relief that you didn’t let this become a refusal.

References

1. Long D, Koyfman A, Long B. The Thunderclap Headache: Approach and Management in the Emergency Department. J Emerg Med. 2019 Jun;56(6):633-641. doi: 10.1016/j.jemermed.2019.01.026. Epub 2019 Mar 14. PMID: 30879843.
2. Schwedt TJ. Thunderclap Headache. Continuum (Minneap Minn). 2015 Aug;21(4 Headache):1058-71.
3. Sekhon S, Sharma R, Cascella M. Thunderclap Headache. [Updated 2023 Jun 4]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK560629/
4. Claassen, J., & Park, S. (2022). Spontaneous subarachnoid haemorrhage. Lancet (London, England), 400(10355), 846–862. https://doi.org/10.1016/S0140-6736(22)00938-2
5. Greving JP, Rinkel GJ, Buskens E, Algra A. Cost-effectiveness of preventive treatment of intracranial aneurysms: new data and uncertainties. Neurology. 2009 Jul 28;73(4):258-65. doi: 10.1212/01.wnl.0b013e3181a2a4ea. Epub 2009 Mar 18. PMID: 19299311.
6. Juarez JI. Diagnosis and Management of Subarachnoid Hemorrhage. Continuum (Minneap Minn). 2015 Oct;21(5 Neurocritical Care):1263-87.
7. Martin, C. O., & Rymer, M. M. (2011). Hemorrhagic stroke: aneurysmal subarachnoid hemorrhage. Missouri Medicine, 108(2), 124–127.
8. Headache Classification Committee of the International Headache Society (IHS) The International Classification of Headache Disorders, 3rd edition. Cephalalgia. 2018 Jan;38(1):1-211.

About the Author

Frances Hall, NREMT-P, works as the one and only C Shift Paramedic in Granite Falls Fire District 17 in Washington State. She presented on improvising junctional tourniquets at the 2023 EMS World Expo following a win at the 2022 EMS World Expo "Stand and Deliver" contest. She has a bachelor's in Biology from Earlham College and an NREMT-P from Tacoma Community College.