When the Most Feared Headache Presents

This transcript has been edited for clarity. Andrew N. Wilner, MD: Welcome to Medscape. I’m your host, Dr Andrew Wilner. Today, I have the pleasure of speaking with Dr Eric Baron. Dr Baron is a neurologist and headache specialist at the Cleveland Clinic. He is also the creator and blogger at virtualheadachespecialist.com. We’re going to discuss a less common headache type today, but a very important one: thunderclap headache. Welcome, Dr Baron.Eric P. Baron, DO: Thank you. Glad to be here. Appreciate the invite.Wilner: Dr Baron, neurologists deal with all kinds of problems of the central and peripheral nervous system, but is your practice 100% headache?Baron: I’m a neurologist by training, with headache fellowship training. My practice is pretty much all headache, migraine, and facial pain, but there’s always some neurology that comes with that, too. Clinically, it’s mostly headache disorders.Wilner: What is virtualheadachespecialist.com?Baron: This is a website that I created some years ago for free public education because there’s really a shortage of headache specialists, at about a little over 700 in the US. There are long wait times and large amounts of anxiety when people are waiting to get in to see the headache specialist. I wanted to create a site which would give further self-education where people could get some information about headaches, symptoms, and things to talk to their doctor about.Wilner: There are 700 headache specialists. How many people in the US with headaches?Baron: About 39 million is the estimate, and about 3 billion globally, so it’s a huge disorder. About 1 in 5 women have migraine, so about 20% of women, and 1 in 16 men. It’s a very underrecognized but very common disorder.Thunderclap Headache: Ominous Sign vs Benign Syndrome Wilner: Let’s dive into thunderclap headache. What’s that?Baron: Thunderclap headache is one of the most feared headache disorders. Medical students, residents, and everybody knows this term. Some people call it the worst headache of your life, but this, by definition, is a severe headache. It reaches maximum pain intensity within 60 seconds, and it has to last for 5 minutes or more. The character and location can vary, but those are really the core features of the disorder.Wilner: As a medical student, I remember learning that the reason this is so important is that it could represent a ruptured or leaking cerebral aneurysm, which has to be addressed right away. Is that always the cause?Baron: It’s not always the cause, but it’s definitely the thing that you need to exclude first. Only about 10%-25% of thunderclap headache presentations are due to aneurysmal subarachnoid hemorrhage, where the aneurysm ruptures and bleeds into the brain. The problem is that, although it’s not the majority of cases that present, if you miss it, it could be catastrophic.The reason is because 10%-18% of these patients with a true thunderclap headache from an aneurysm rupture don’t make it to the hospital. They die before they get there. Of the patients that survive, there’s a 1-year mortality rate of about 35%-65%. This is why it’s so important to make sure it’s definitively been excluded. If you miss it, the patient is not going to do well.There’s certainly a number of other things that can present with a thunderclap headache-like presentation. The way I group these in my head is I first think about the vascular causes, so certainly aneurysm rupture is the number one thing you want to rule out. The next thing is reversible cerebral vasoconstriction syndrome (RCVS). The next one is arterial dissection, whether that’s carotid artery dissection or vertebral artery dissection. Cerebral venous thrombosis, where you get a blood clot in the venous drainage system of the brain. The fourth vascular one I think of is stroke, usually more of an intraparenchymal hemorrhage of some type.There’s a number of nonvascular causes of thunderclap headache. The first one that you certainly want to rule out is meningitis. This is going to usually present with fever, stiff neck, photophobia, and those typical meningitis symptoms, but it can present very quickly like that.A less common one is pituitary apoplexy, which is quite infrequent but is something that you want to still keep in the differential. The other thing I think about is a cerebrospinal fluid (CSF) leak. This can present with a sudden thunderclap headache and a sudden drop in CSF pressure, and it can cause that kind of headache.There’s a number of other things, too, but those are the top vascular and nonvascular differentials that I personally like to think about.Wilner: Even if it’s not a ruptured aneurysm, some of the other causes are also potentially life-threatening.Baron: All of these things that I mentioned potentially could be life-threatening. Once all of these bad things have been ruled out, there are benign thunderclap headache syndromes where you can get this thunderclap headache that just comes on abruptly.Occasionally, we do see migraine that presents like this, but this is a diagnosis that’s made after you’ve established a recurrent pattern of these symptoms. With migraine, for example, there should be migrainous features with the light and sound sensitivity and nausea, which you certainly can get with the other diagnoses that I mentioned as well. It’s really that recurrent pattern and exclusion of all the other possibilities with diagnostics before you assume it’s a benign thunderclap headache syndrome.Workup Algorithm Wilner: Hypothetically, I’m in the ER and a patient comes in with the worst headache of her life. Do you have an algorithmic approach to imaging or lumbar puncture? What’s the first thing I should do?Baron: There’s a large amount of confusion about this and the timing of what tests. The first thing is to do a noncontrast CT scan. A non-contrast CT scan within 6 hours is 99%-100% sensitive at picking up an aneurysmal subarachnoid hemorrhage. It’s actually quite sensitive. For patients that come in after 6 hours, that sensitivity starts to drop off. The other test that you always want to do with the CT is CT angiography (CTA), and this helps to rule out many of other possibilities that I mentioned, like RCVS, arterial dissections, and those kind of things.If the patient does come in after 6 hours, the headache has been going on for a while, and the CT is negative, then we consider doing a spinal tap to check the CSF. We’re looking for xanthochromia, or a breakdown of the red blood cells. Now, you know, there’s a lapse there because the most sensitive window of picking up xanthochromia is between 12 hours and up to 2 weeks. There is a little bit of an overlap in time. If there’s a high clinical suspicion — even if the CT is done early, within 6 hours, say it’s negative, but there’s still a very high clinical suspicion for a subarachnoid hemorrhage — then usually we’ll still pursue lumbar puncture (LP) to check the spinal fluid.When that’s all done — the CT, CTA, and spinal tap — if there are ongoing symptoms and there’s still not a clear answer, then usually we’ll go to MRI. If they’ve not had vessel imaging, the MRA, then magnetic resonance venography is what we would also add to look at the venous drainage systems. This would rule out venous thrombosis. This would look at the pituitary. This would look for inflammation if there are signs of meningitis and meningeal enhancement, and those kind of things.Wilner: Clinically, thunderclap headache has to last longer than 5 minutes, but how often does it last hours and hours? Is it just a quick thing and then it’s gone?Baron: If it’s a benign thunderclap headache, most of the time it’ll resolve after a couple of hours, but it really is variable. By definition, if it’s at least 5 minutes, it can fit into that category of thunderclap headache. For some people, it can persist for days or even longer. We certainly see that in clinic as well.Wilner: Suppose it turns out that we’ve imaged this patient over the last 12 hours. They’ve had an LP and the headache is maybe going away now, but they’re still suffering. Are there dos and don’ts? We think this is something to do with vasoconstriction, right, so are there drugs that we shouldn’t use? Baron: In the acute setting, we would usually try to avoid triptans and dihydroergotamine. Medicines that are going to cause vasoconstriction, ultimately, are what we would want to avoid. Now, if this is a headache that’s been going on and all the testing is good, there’s no clear narrowing or vasoconstriction, later on these medicines might become an option if it’s a recurrent benign thunderclap headache syndrome. The first time this happens, usually we would want to avoid these medicines within the first few weeks, just because RCVS is known to sometimes come on like a thunderclap headache. The difference is that you can get this recurrent thunderclap headache for a few days or up to a week or two.The vasoconstriction that you might see — what we call the “string of beads,” where you have areas of stenosis in those vessels and then dilation — is a reversible syndrome, but sometimes it may not present right away. You may not see it at the first sign of symptoms, and it can sometimes come on a few days later. We would still want to avoid those medicines for the first attack, just in case it’s an evolving RCVS-type syndromeRepeat Presenters Wilner: I can imagine a patient might come back with a second or third thunderclap headache. Do we need to do the whole workup each time?Baron: If it’s a new syndrome and they’ve had a second event, usually we will pursue most of the testing, but maybe not with the repeat spinal tap and all that. It depends on the story. The reason for that is with subarachnoid hemorrhage and aneurysm rupture, there is a group of patients that have what we call a sentinel bleed, where they have a small rupture in the aneurysm days or a couple weeks before. It’s a bad headache, but then it just kind of spontaneously resolves. The problem is that if they come back with another severe thunderclap headache, sometimes that can signal the full-blown rupture of that aneurysm. That’s why we still are very cautious. If it’s a pattern that this person has the same exact presentation numerous times over months to years, then we treat it more like a benign thunderclap headache, unless there are some new features in that presentation, like new neurologic symptoms or something that’s much different from their usual pattern.Wilner: Dr Baron, this has been an incredibly informative 10 minutes. We’re running out of time. Is there anything you’d like to add or advice to share with practitioners?An Aneurysm Till Proven Otherwise Baron: I would say the main thing is that thunderclap headache is not something you want to miss. Especially the first or second time, you want to treat it as an aneurysm rupture until proven otherwise, because the results if you don’t catch it and treat it are catastrophic for the patient.Then you start to think about these other possibilities like RCVS, and RCVS can also be caused by a number of decongestants and sympathomimetic medications. That’s a whole other conversation. The key is that you don’t want to overlook it when these patients come in because it could be real. The majority of time it’s not, but if it is, you don’t want to miss that.Wilner: Dr Eric Baron, thanks for teaching us about thunderclap headache.Baron: Thank you very much.Wilner: I’m Dr Andrew Wilner, reporting for Medscape.Andrew Wilner is a professor of neurology at the University of Tennessee Health Science Center, Memphis, and a seasoned neurologist and epilepsy expert who has mastered the less conventional locum career path. He is the author of four books, including Bullets and Brains, and hosts the podcast The Art of Medicine with Dr. Andrew Wilner.