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Figure: HINTS, vertigoFigureEmergency physicians generally dislike seeing vertigo patients, mostly from the fear that the dizzy patient they send home with a benign diagnosis may return in the next few days with a bad outcome from a posterior circulation stroke (PCS). The first line of defense against missing a PCS is not the HINTS (Head Impulse test, Nystagmus, Test of Skew) exam, however. All dizzy patients should be screened for central features that would bring the diagnosis of a benign cause of dizziness into question and thus warrant a workup for a central cause. Those central features include a new significant headache or neck pain, focal paresthesia or motor weakness, inability to walk unaided, spontaneous vertical nystagmus, or any of the dangerous Ds (dysarthria, diplopia, dysmetria, dysphonia, dysphagia). (YouTube. Aug. 29, 2018; https://bit.ly/3ixoU9K.) To determine which kind of bedside testing is warranted, it's all about nystagmus. (YouTube. Oct.7, 2019; https://bit.ly/3ixpeFu.) If the patient screens negative for these central features and has short episodes of vertigo brought on by position change and no spontaneous nystagmus, positional testing (Dix-Hallpike and supine roll test) can determine if he has benign paroxysmal positional vertigo (BPPV). If the patient has constant vertigo worsened by head movement, nausea or vomiting, difficulty walking, and spontaneous or gaze-evoked nystagmus, he has the acute vestibular syndrome (AVS), and a HINTS exam should be used. Most AVS patients will be suffering from vestibular neuritis (VN), but a small number, despite being screened for central features, will have a PCS. HINTS can be a valuable safety net to prevent missing a PCS that was not picked up by central feature screening. It's not hard to understand why these indications for bedside testing of vertigo are commonly misunderstood when some authors recommend using HINTS in patients without nystagmus. Edlow confusingly instructs his readers to use the head impulse test (HIT) in patients without nystagmus but not to rely on it. (Emerg Med Pract. 2019;21[12]:1; https://bit.ly/37rr30t.) Gerlier, et al., trained emergency physicians to apply HINTS to patients with “acute vertigo,” but did not add nystagmus to the inclusion criteria. (Acad Emerg Med. 2021 Jul 10. https://bit.ly/3xwlF6z.) HINTS missed only one ischemic stroke of 62 central causes of vertigo, but it miscategorized 24 of 90 BPPV patients as central. This likely would not have occurred if only patients with nystagmus had been included. Not the Wrong Doctors? Emergency physicians are the right doctors with the wrong training. AVS patients often present to the ED, so we are the ideal clinicians to properly apply HINTS to safely send home the majority of AVS patients who have vestibular neuritis. After screening negative for central features and demonstrating an abnormal HIT as well as unidirectional nystagmus and no vertical skew, a patient with VN can be safely discharged from the ED without diagnostic imaging. Because most patients with AVS will be having VN, seeing an abnormal HIT in VN prepares us for the rarer patient with an AVS who screened negative for central features but has a PCS with a normal HIT. How Much Training? I wholeheartedly agree with Dr. DeLaney that improper patient selection and undertraining is a major impediment to using HINTS correctly in assessing dizzy patients. What is the solution? Dr. DeLaney points out that six hours of training can make an emergency physician capable of using HINTS properly. I would argue that introducing the concept of HINTS as early as medical school and having appropriate didactic vertigo education and clinical practice over the course of an emergency medicine residency could easily incorporate HINTS into the wheelhouse of our graduating residents. If you know how to screen vertigo patients for central features, how to select the right patient for the HINTS exam, have been observed to perform the HINTS exam correctly by a vertigo champion, and you can describe and chart findings of the three components of the HINTS exam without referring to your notes, you can probably use the HINTS exam in clinical practice. This is not dissimilar to how we decide that learners are signed off on rapid sequence intubation and ultrasound to look for free fluid. I'm old enough to remember when it was thought that EPs could not perform ultrasound or RSI. Do We Get It Wrong? Any procedure, bedside examination technique, or decision rule that proved to be safe in a study can be misused or misinterpreted when applied by practitioners without the appropriate training. The misuse of a good test, however, should not be a reason to stop trying to use it properly. Despite that the gold standard test (YouTube. Dec. 2, 2019; https://bit.ly/3izLHC0) and cure (YouTube. Feb. 24, 2020; https://bit.ly/3lMFsfZ) for BPPV (the most common cause of vertigo seen in the ED) have been known for 70 and 30 years, respectively, a recent study by Neely, et al., showed that only 45 percent of those diagnosed with BPPV in an Australian ED were diagnosed using the Dix-Hallpike test, only 41 percent had treatment with the Epley maneuver, and 36 percent had an unnecessary CT head. (Emerg Med Australas. 2021 Jun 6; https://bit.ly/3CzQj2H.) We continue to blunder through BPPV, and PCS is missed in the ED 37 percent of the time. (Stroke. 2016;47[3]:668; https://bit.ly/3xujYXj.) Vestibular migraine, a common cause of vertigo, is almost never diagnosed by EPs. What to do then with vertigo education? Keeping the status quo will give us the same poor results that our patients have endured for decades and condemn our learners to being oblivious to proper bedside testing of vertigo. The fact that we are currently getting BPPV, PCS, and vestibular migraine so wrong speaks volumes about the inadequacy of vertigo education. We haven't stepped up to the plate with proper assessment and treatment of BPPV after 30 years, so what is the chance that we will get better at vertigo unless we rethink vertigo education? And that includes teaching ourselves how to use HINTS properly. Share this article on Twitter and Facebook. Access the links in EMN by reading this on our website, www.EM-News.com. Comments? Write to us at [email protected]. Dr. Johnsis an emergency physician at the University of Ottawa. Follow him on Twitter@peterjohns84, and visit his YouTube channel athttps://www.youtube.com/user/peterjohns84.

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