What if I told you that I think that patient you just sent home with vertigo may have been a missed cerebellar stroke? Would you be dialing risk management or could you tell me all of the reasons why I’m wrong? Isolated vertigo without other neurological findings can’t be a stroke, right? That is true, if you are doing the right exam, but if you are just doing your standard ED neuro screening exam then you might be missing serious pathology. In this episode of the EMCrit podcast, I discuss how to perform the tests that will differentiate a peripheral cause of continuous vertigo from a cerebellar stroke.
Drs. David Newman-Toker & Jorge Kattah, neurologists at John Hopkins, have done a ton of work on this topic. They have created an mnemonic for the exam you should be doing on all of your patients with continuous vertigo (as opposed to positional, intermittent vertigo, i.e. BPPV). Benign positional paroxysmal vertigo is not ED critical care. Continuous vertigo, also known as acute vestibular syndrome, may be. The mnemonic is HiNTS.
Hi for head impulse testing, or head thrust testing.
N for nystagmus to remind you to look for direction-changing or vertical nystagmus
TS for test of skew.
I will discuss what all of these terms mean and how to perform the exams in the podcast.
Here is the HiNTS article.
Here is a link to another study by the same authors on head impulse testing.
Here is a fantastic review article by James A. Nelson on the topic.
Here is a video demonstrating the exam with positives and negative examples.
Update
Insanely good systematic review on Dizzy Stroke Patients (CMAJ 2011;183(9):E571)
Podcast: Play in new window | Download (10.7MB) | Embed
Hi, my name is Scott Weingart. 
Scott-
Outstanding lecture at Cornell yesterday!
I was pretty excited about David Newman-Toker’s papers at first, but I’ve become a little skeptical that the HiNTS battery — in particular, the head impulse test — is a magic test for detecting cerebellar stroke in the ED.
First of all, the head impulse test is tricky to perform, and the result you’re looking for is quite subtle. And although all the papers say you can perform the test in the presence of spontaneous nystagmus, a non-expert (like me) has a lot of trouble distinguishing nystagmus from a catch-up saccade when the patient’s eyes are bopping around like crazy.
Second, it’s really impossible to perform the test in someone with severe head-motion intolerance — for example, our acutely dizzy patients early in their course. Diaphoretic, ashen, vomiting, eyes clenched shut and holding their heads perfectly still — there’s no way these patients will tolerate having their heads snapped back and forth, much less open their eyes and fix on a target.
In Newman-Toker’s HIT paper, the average time from symptom onset to exam was about 10 1/2 hours, and many patients were examined days after onset — by which time I bet most of them were pretty comfortable. But that’s not most of our patients. So it’s a great test for the Neurology team upstairs the next morning, or a few days later in clinic, but not so great early on, when we need it most. I think we’re better off looking for red flags — especially headache or neck pain, or unsteadiness out of proportion to spinning. That’ll catch most of our cerebellar strokes.
Dr. Lappin,
pleasure to meet you.
Your comments are well received.
I think I need to clarify for which patients I believe the HINTS exam is important.
If the patient has any worrisome signs, i.e. the profound ataxia you mention, a headache in association with the vertigo, any hard neurological findings, then no HINTS necessary–pursue MRI and neurological consultation. Or if the patient is elderly (though I don’t have an exact age cut-off for when that designation begins), they probably should be admitted with neurology onboard regardless of the HINTS exam.
But if you have a patient with isolated vertigo with a pristine routine neuro exam, who you were about to send home, then HINTS becomes very valuable. If the HINTS exam is non-reassuring, then that is a potential save.
So I use HINTS as a last fail safe and not as a means to discharge a patient I was concerned about prior to doing the test.
As to performing the Head Impulse, I agree it certainly it can be tough sometimes. However, for me it is the BPPV patients that have the extreme head motion intolerance. Most of the AVS patients (continuous vertigo, with only mild positional component) can tolerate the test.
Let me know what you think.
Scott
I completely agree with your strategy of using HiNTS as a fail-safe.
My experience is a little different — my BPPV patients don’t (and, I think, shouldn’t) have head-motion intolerance in the horizontal plane (for example, the head-impulse test), only in the vertical plane (the Dix-Hallpike). As for the patients with continuous vertigo, many are — as you say — comfortable by the time they come to us. The ones who aren’t are a real challenge for any sort of testing.
In general, I think the difficulty with vertigo comes at the beginning, with the basics. A lot of docs don’t realize, for example, that brief dizzy spells and long, continuous attacks have a completely different differential diagnosis. As a result, they order MRIs for older patients with BPPV to rule out (nonexistent) strokes, and perform the Dix-Hallpike maneuver on patients with continuous vertigo (inevitably the patients feel worse on one side than the other, leading to a spurious diagnosis of BPPV).
Our subspecialty consultants are often just as confused. A few weeks ago a Neurology consult informed me that my patient — an elderly woman with three days of constant vertigo, vomiting and ataxia — “clearly” had BPPV because she had “a positive Epley maneuver to the left.” Sigh.
Ahem. Rather a specialty subconsultant?
Scott,
Quick question.
In some recent shadowing experience I did in the emergency room here in Tennessee. The doctor and I were discussing vertigo and different ways to determine things clinically. He had heard of this “head impulse test” in medical school and had used it a couple of times in residency but has since moved away from it. When I asked about his reasoning he said “Next patient we get in here with vertigo, try that test. They may vomit all over your shoes and scrubs, and I can promise you they are not going to be very happy with the care they received. haha”
What I was asking is have you seen this in your practice and what are you doing to get around it?
Cause it makes sense, I mean if you take a person that is already dizzy and turn their head quickly they are not going to be very happy.
Needless to say, we didn’t see another vertigo that day.
Thanks again,
Dax
Dax,
Key is not to try this test on the positional vertigo patients. The folks with continuous vertigo generally won’t vomit on you from moving their head around especially in the horizontal plane. Try the test on a bpv patient and you may need a change of scrubs, but it’s not helpful on these patients anyway.
scott
Scott,
I just came across this Podcast and was somewhat surprised by it. Why was critical analysis of these tests left out? No mention of sensitivity and specificity and how applicable and helpful these tests would be to the undifferentiated vertiginous patient who presents to the ED?
I can’t imagine attempting to order an MRI or transfer a patient to get one based on a NORMAL head impulse test.
Skew deviation may-be predictive of badness, but I’d be very surprised if this was your only abnormal neurologic symptom, as in you were about to send the patient home, but hold on, their alternate cover test detected vertical ocular misalignment, patient is saved from being discharged with horrible cerebellar stroke. Instead gets admitted where…. no intervention could be done anyway.
It’s like we went to the archive and found Kernig and Brudzinski tests, and are now touting them as being clinically useful.
Unleashing these tests on the average ED practitioner without a thorough understanding of which subset of patients to perform them in, and without an understanding of the limitations of these tests seems unlikely to be helpful and more likely to cause confusion and over testing.
Just my 2 cents
Marcus
Marcus,
Thanks for writing! Before I respond, let me ask a few questions:
1. Did you listen to the podcast? I am not asking that to be flip; many folks comment just based on the blogpost?
2. Did you read the linked articles discussing the test characteristics?
3. Did you read the comments above?
4. Could you tell us your level of training and type of practice?