So three very different papers for you this month…
We start off having a look at a paper on the HINTS examination. This exam came to prominence a few years ago as a way to distinguish between central and peripheral causes of vertigo with a pretty amazing sensitivity and specificity. Since then many EM clinicians have brought it onto their practice and this paper seeks to assess how good the test is at the bedside in real life practice.
Next up we take a look at a paper assessing the injury patterns in trapped patients and consider the prevalence of injuries both with regard to spinal and other injury patterns and then consider the impact that this holds with respect to extrication.
Finally we have a look at a paper focussing on the inhospitable management of hypertension; the treatment strategies and the outcomes comparing those being treated during their inpatient stay versus this left untreated with some surprising outcomes…
Once again we’d love to hear any thoughts or feedback either on the website or via twitter @TheResusRoom.
Simon & Rob
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Excellent and very fair review of the HINTS paper. Your points about being sure that you are meeting the criteria for AVS (documenting presence of spontaneous or gaze evoked nystagmus) were spot on.
A few points:
Not only should you not perform HINTS in patient WITHOUT spontaneous or gaze evoked nystagmus, such as in BPPV, but HINTS shouldn’t be performed or relied upon when patients have central features that are inconsistent with peripheral causes of AVS.
The major differential in AVS is: is this vestibular neuritis or is this a posterior circulation stroke?
If a patient has arm or leg numbness, or focal weakness or dysarthria, or true diplopia, dysmetria, new and significant headache or neck pain, or inability to walk unaided, or spontaneous nystagmus which is vertical, then this is NOT consistent with vestibular neuritis, and HINTS is irrelevant. These patients should be worked up for stroke.
HINTS is really meant to tease out the vestibular neuritis patients from the posterior circulation stroke patients who have NONE of the above features (so called pseudo-vestibular neuritis).
And in the emergency department, vestibular neuritis is far more common than stroke presenting with pseudo-vestibular neuritis.
So the implication of this are that you should first screen all patients with vertigo for central features, as I suggest in the central part of my algorithm. https://www.cmaj.ca/content/192/8/E182/tab-figures-data
If they screen negative but have persistent, continuous vertigo AND nystagmus, then most of them will have vestibular neuritis. And there is only one pattern of HINTS that will confirm the diagnosis of vestibular neuritis and allow you to send them home without imaging. Unidirectional (not changing with gaze) nystagmus, no vertical or diagonal skew, and seeing an abnormal head impulse test (a catch up saccade seen when the head is turned rapidly in the opposite direction of the fast component of the nystagmus).
So then the real power of HINTS in the ED is to be able to identify reliably vestibular neuritis, and thus rule out stroke in these patients.
And yes the head impulse test is the hardest part of the HINTS exam to perform and interpret. But is it really beyond the skill of emergency physicians to learn? Of course not.
Will people who merely watch a video once become skilled at it? I doubt it very much. This study would seem to support that.
So what is the alternative? Admit and MRI all patients with AVS? Not viable in Canada, and I suspect not in the UK either.
Send home suspected vestibular neuritis without a HINTS exam and just hope you’re right? Very dangerous from a patient and medicolegal perspective.
I hope what will happen is that learners will be exposed to HINTS from medical school level and through their training enough that when they are sent out in the wild to assess the undifferentiated dizzy patient they will know how to screen for central features, apply HINTS to the right patient and when they see vestibular neuritis with an abnormal head impulse test (and other components negative) they will send them home. All others with AVS would worked up for stroke.
If this actually comes to fruition, we will miss less strokes and save money on unwarranted diagnostic imaging.
My two cents anyway