Is Your Head Spinning? The Sudbury Vertigo Risk Score

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Ohle R, Savage DW, Roy D, et al. Development of a Clinical Risk Score to Risk Stratify for a Serious Cause of Vertigo in Patients Presenting to the Emergency Department. Ann Emerg Med 2024

Aims

The authors cite a wide variation in practice, particularly in obtaining neuro-imaging in patients presenting with vertigo. Many patients are imaged and subjected to a longer length of stay, and on the other side of the coin, some patients with serious pathology fall through the cracks. They set out to create a risk score to apply to patients who present to the ED with vertigo which would identify the patients at risk for serious pathology (which they defined as stroke, TIA, vertebral artery dissection, or brain tumor).

Methods and Results

This study was carried out at 3 university-affiliated, urban teaching hospitals in Canada over the course of approximately 3 years. Patient’s over the age of 18 presenting with a chief complaint of vertigo, dizziness, or imbalance were eligible to be enrolled. For eligible patients, the attending or resident physician seeing the patient completed a form that included elements from the patient’s past medical history, characteristics of their current presentation, and physical exam findings. The form included information that, based on literature review and expert opinion, was thought to be either positively or negatively associated with one of the serious outcomes.

Enrolled patients were then followed up following their initial Emergency Department visit. Investigators performed chart review for subsequent ED visits or visits at Neurology or Stroke clinics, radiology reports, and autopsy reports. They also performed follow-ups via telephone calls at 7, 30, and 90 days following the initial presentation and used a validated questionnaire to screen for stroke.

Using logistic regression models, investigators identified 7 variables independently associated (either positively or negatively) with a serious outcome. These variables were then assigned points by dividing by the variable with the smallest beta-coefficient and rounding to the closest whole number, yielding the Sudbury Vertigo Risk Score. Investigators then analyzed the percent of patients found to have a serious outcome for each possible score on the Sudbury Vertigo Risk Score. They found that in their study population, 0% of the patients with a serious outcome would have scored < 4, giving the Sudbury Vertigo Risk Score a sensitivity of 100% when using this cutoff. The authors propose that if the SVRS is validated, it can be used to identify patients that are low-risk and can be safely discharged without imaging, as well as those that are high risk and would benefit from further work-up.

Limitations

The most obvious limitation, which is outlined by the authors multiple times within the paper, is that this risk score has not been externally validated. This would obviously need to occur before it is appropriate for use in clinical practice.

Another limitation that is discussed is how “stroke” and “TIA” were determined in the study. Many of these patients didn’t have imaging performed at all, let alone an MRI. If you remember as we discussed in the Methods section, a lot of the data regarding patient outcomes was extrapolated from phone calls following their initial ED presentations. T o accomplish this they used the World Health Organization (WHO) definitions.

  • Stroke: Rapidly developed clinical symptom(s) of focal (or occasionally global) disturbance of cerebral function lasting more than 24 hours or until death with no apparent nonvascular cause.

  • TIA: Sudden, focal neurologic deficit lasting for less than 24 hours, presumed to be of vascular origin, and confined to an area of the brain or eye perfused by a specific artery.

The authors of the study do cite this as a limitation. They suggest that they may have actually over-estimated the prevalence of stroke and TIA because this definition may include patients with stroke mimics. Use of these broad definitions rather than gold standard diagnostics has other potential issues. Without MRI data, it is quite possible that small strokes were missed.

Integration into practice

Vertigo continues to be an anxiety-inducing chief complaint. Unlike the physical-exam based tools that we currently possess (HINTS exam, STANDING algorithm) to help distinguish between central and peripheral causes of vertigo, the Sudbury Vertigo Risk Score adds something that we intuitively understand about stroke risk; that factors like age and medical comorbidities are strong contributors. Conversely, we probably don’t need a clinical decision tool to tell us that a patient with obvious neurologic deficits on a physical exam is at risk for a serious cause of their vertigo.

We are not ready to add this to our practice pattern yet. First and foremost, this tool would need to be externally validated before we use it to make clinical decisions. We would also like to see more robust investigation of potential serious causes of vertigo (MRI, etc.) to ensure that these patient’s don’t continue to fall through the cracks.

Authorship

Written by Colleen Arnold, MD, PGY-3 University of Cincinnati Department of Emergency Medicine

Peer Review, Audio Editing, Posting by Jeffery Hill, MD MEd, Associate Professor, University of Cincinnati Department of Emergency Medicine

Cite As: Arnold, C. Hill, J. Is Your Head Spinning? The Sudbury Vertigo Risk Score. TamingtheSRU. www.tamingthesru.com/blog/journal-club/vertigo-risk-score. 9/18/2024