P014: Does a positive Dix-Hallpike rule out a central cause of vertigo?

Abstract

Introduction: Dizziness is a common presentation in emergency departments (ED), accounting for 2-3% of all visits. The majority are due to benign causes the most common of which is benign paroxysmal positional vertigo (BPPV). The Dix-Hallpike maneuver is used to diagnose BPPV with an affected posterior semicircular canal. A positive Dix-Hallpike exam should lead physicians to exclude central causes for a patient's symptoms and confirm no need for further imaging. The purpose of our study was to verify the accuracy of the Dix-Hallpike maneuver for ruling out a central cause of dizziness. Methods: We performed a medical records review of adult patients with dizziness/vertigo presenting to a tertiary care ED (September 2014 and March 2018). We included those with a suspicion for BPPV and underwent a Dix-Hallpike maneuver. We excluded patients who presented with dizziness for longer than two weeks, syncope, systolic hypotension <90 or a GCS <15. Individual patient data were linked with the Institute of Clinical Evaluation Science (ICES) database. Our outcome was a central cause defined as: ischemic stroke (IS), brain tumour, intra cerebral haemorrhage (ICH), or multiple sclerosis (MS) diagnosed on either neurology assessment, computed tomography, magnetic resonance imaging, or diagnostic codes related to central causes found within ICES. Results: 3109 patients were identified of these 469 patients underwent a Dix-Hallpike manoeuvre. Central causes of dizziness accounted for 1.1% of all diagnoses. Probability of a central cause for dizziness in those with a positive Dix-Hallpike was 1.3%(3/229). Only 85(18.1%) patients were appropriate for the Dix-Hallpike(intermittent, position-evoked vertigo without any neurological deficits). In appropriate patients the prevalence of central cause of dizziness was 3%(1/31). This patient had > 3 risk factors for stroke (age > 65, hypertension, diabetes, ischemic heart disease). A positive Dix-Hallpike in appropriate patients with <3 risk factors for stroke was 100% (95%CI 88.8% -100%) sensitive in ruling out a central cause for dizziness. Conclusion: The Dix-Hallpike manoeuvre is performed on a large number of inappropriate patients. When performed on appropriate patients with <3 risk factors for stroke a positive Dix-Hallpike can rule out a central cause of vertigo. Educating physicians as to the appropriate patient population could reduce unnecessary imaging and improve diagnostic accuracy.