SGEM#310: I Heard A Rumour – ER Docs are Not Great at the HINTS Exam

Date: November 30th, 2020 Reference: Ohle R et al. Can Emergency Physicians Accurately Rule Out a Central Cause of Vertigo Using the HINTS Examination? A Systematic Review and Meta-analysis. AEM 2020 Guest Skeptic: Dr. Mary McLean is an Assistant Program Director at St. John’s Riverside Hospital Emergency Medicine Residency in Yonkers, New York. She is the New York ACEP liaison for the Research and Education Committee and is a past ALL NYC EM Resident Education Fellow.  Case: A 50-year-old female presents to your community emergency department in the middle of the night with new-onset constant but mild vertigo and nausea. She has nystagmus but no other physical exam findings. You try meclizine, ondansetron, valium, and fluids, and nothing helps. Her head CT is negative (taken 3 hours after symptom onset). You’re about to call in your MRI tech from home, but then you remember reading that the HINTS exam is more sensitive than early MRI for diagnosis of posterior stroke. You wonder, “Why can’t I just rule out stroke with the HINTS exam? How hard can it be?” You perform the HINTS exam and the results are reassuring, but the patient’s symptoms persist…  Background: Up to 25% of patients presenting to the ED with acute vestibular syndrome (AVS) have a central cause of their vertigo - commonly posterior stroke. Posterior circulation strokes account for approximately up to 25% of all ischemic strokes [1]. MRI diffuse-weighted imagine (DWI) is only 77% sensitive for detecting posterior stroke when performed within 24h of symptom onset [2,3]. As an alternative diagnostic method, the HINTS exam was first established in 2009 to better differentiate central from peripheral causes of AVS [4]. But what is the HINTS exam? It’s a combination of three structured bedside assessments: the head impulse test of vestibulo-ocular reflex function, nystagmus characterization in various gaze positions, and the test of skew for ocular alignment. When used by neurologists and neuro-ophthalmologists with extensive training in these exam components, it has been found to be nearly 100% sensitive and over 90% specific for central causes of AVS [5-8]. Over the past decade, some emergency physicians have adopted this examination into their own bedside clinical assessment and documentation. We’ve used it to make decisions for our patients, particularly when MRI is not readily available. We’ve even used it to help decide whether or not to get a head CT. But we’ve done this without the extensive training undergone by neurologists and neuro-ophthalmologists, and without any evidence that the HINTS exam is diagnostically accurate in the hands of emergency physicians. Clinical Question: Can emergency physicians accurately rule out a central cause of vertigo using the HINTS examination? Reference: Ohle R et al. Can Emergency Physicians Accurately Rule Out a Central Cause of Vertigo Using the HINTS Examination? A Systematic Review and Meta-analysis. AEM 2020 Population: Adult patients presenting to an ED with AVS Exclusions: Non-peer-reviewed studies, unpublished data, retrospective studies, vertigo which stopped before or during workup, incomplete HINTS exam, or studies with data overlapping with another study used Intervention: HINTS examination by emergency physician, neurologist, or neuro-ophthalmologist Comparison: CT and/or MRI Outcome: Diagnosis of HINTS examination for central cause for AVS (i.e., posterior stroke) Authors’ Conclusions: “The HINTS examination, when used in isolation by emergency physicians, has not been shown to be sufficiently accurate to rule out a stroke in those presenting with AVS.” Quality Checklist for Systematic Review Diagnostic Studies:  The diagnostic question is clinically relevant with an established criterion standard. Unsure The search for studies was detailed and exhaustive. Yes The methodological quality of primary studies were assessed for common form...