August 2023

Clinical Question

Another addition to the vertigo assessment armamentarium – how accurate is it?

Title of Paper

Effectiveness and reliability of the four-step STANDING algorithm performed by interns and senior emergency physicians for predicting central causes of vertigo.

Journal and Year

Academic Emergency Medicine. 2023.

Lead Author

Camille Gerlier

Background

• Vertigo – it remains one of those “easy but hard” presentations that most people hate picking up in the triage pile. Regular listeners will have heard me rant on this before (April 2021) and my registrars and residents have to hear me rant about it often.
• The STANDING algorithm was validated in 2017 to have Sn 95%, Sp 87% and NPV 99% for central vertigo.
• It assesses:
  • Discrimination between SponTAneous and positional nystagmus
  • Nystagmus Direction
  • Head Impulse test
  • Evaluation of equilibrium (staNdinG)

(I have to take a moment here to say that as tenuous means of squeezing a word out of a study does – this really takes the biscuit.)

Anyway, the algorithm is here:

Basically, you do a good clinical assessment algorithm for vertigo. If you get signs of possible central, you stop there. If you get signs of peripheral then you test the patient’s ability to stand and walk – and if they can’t then you still get concerned for central

Study Design

• Single-centre, prospective assessment of effectiveness of the STANDING algorithm.
• Tertiary hospital ED in France.

Patients Studied

• Adults
• Presenting with Acute Vestibular Syndrome (AVS) or Episodic Vestibular Syndrome (EVS)
• Had to have one of:
  • Spontaneous or triggered vertigo (false send of motion, spinning or non-spinning)
  • Vestibulovisual symptoms (blur, false sent of motion or oscillopsia)
  • Postural symptoms (loss of balance, unsteadiness)
• Excluded:
  • “Dizziness” because that can mean any number of things
  • Patients with localising neuro signs

What they did

• Trained their interns with refresher in vestibular anatomy, the HINTS exam, the STANDING algorithm, Dix-Hallpike, Supine Roll test, Fukuda test, Epley and Semont Manoeuvres
• All interns observed an assessment and had one supervised assessment of patient with vertigo

Studies application of STANDING:

Step One: Look for nystagmus (with or without Frenzel goggles)

• No spontaneous → Dix-Hallpike/Supine Roll to look for BPPV

Step Two: If spontaneous nystagmus → assessed for direction

• Gaze-evoked, vertical or multidirectional → “worrisome”

Step Three: If spontaneous nystagmus → HIT

• Normal → “worrisome”

Step Four: Positional Nystagmus or positive HIT → assess standing position and gait

• Mild to severe imbalance, directional impulse on walking or inability to stand related to lethargy → all “worrisome”

“Worrisome”: Predictive of central cause

“Benign”: Predictive of peripheral cause

“Inconclusive”: No spontaneous nystagmus, no positional nystagmus, gait was normal

Reference Standard

• MRI-DWI to assess for central cause unless:
  1. BPPV dx by senior EP and validated by otologist through positional tests plus videonystagmgoraphy and video HIT
  2. Contraindication to MRI → CTA

Outcomes

• Primary: dx accuracy of the STANDING algorithm
• Secondary:
  • Comparison of accuracy between interns and EPs
  • Agreement of between interns and EPs
  • Opinions of interns on use and interpretation and the beginning and end of their internship

Summary of Results

• 312 patients – 267 had MRI-DWI, 203 had otologist examination
  • Central 59 patients
  • Peripheral 253

No MRI (n 45):

• 32 had confirmed BPPV

• 10 had contraindication → CTA

• 3 unequivocal for central on CT/CTA

• Some interesting notes from Table One:

  • Peripheral group more likely to present with ‘vertigo’ (69 vs 44%), N&V (70 vs 20%)
  • Central group more likely to present with ‘unsteadiness’ (38 vs 80%) or imbalance (29 vs 66%)

• None of them, not even the proven central group had skew deviation – though in saying that, they weren’t actually including TS as part of the STANDing so maybe that’s why.

Primary outcome:

Dx accuracy of STANDING for dx central vertigo: No sig difference between groups

• Interns: Sn 85% | Sp 89%

  • • LR 4.63
  • • LR 0.09

• EPs: Sn 90% | Sp 91%

  • • LR 10.33
  • • LR 0.01

• Interns missed 9 central diagnoses (one “benign”, 8 “inconclusive”)

• EPs missed 6 (all “inconclusive”)

• Of the 3 that EPs caught:

  • 2 abnormal gaits classified as normal → ischaemic strokes
  • 1 Bidirection nystagmus as unilateral in patient with positive HIT (acute embolic stroke)

Authors Conclusion

After suitable learning, the [four] step bedside STANDING algorithm showed high effectiveness and reliability for predicting central causes of vestibular symptoms, in the hands of both emergency interns and senior emergency physicians. This study should further the adoption of vestibuloocular learning by emergency physicians of all experience levels.

Clinical Bottom Line

The numbers they are getting here as as good as you good possibly get in an ED – 4 hours of specific training, supervised practice and knowledge that there’s an ongoing study into your vestibular assessments. So be careful how you apply these numbers to your own practice.

I think this is another examination / adaption to our usual examination that is more useful from a specificity (rule in) than a sensitivity (rule out) perspective.

It does reaffirm that its important to walk our patients, and I really do think its a vital part of the vertigo/cerebellar/neuro/functional assessment.

Vertigo remains confusing and challenging and you need to really strive to get comfortable with all the examination options and their interpretation – and when in doubt phone a friend.

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Steve Black | Contributor | Health Service Journal

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Clinical Question

What do the ophthalmologists think about take home local anaesthetics for corneal abrasion?

Title of Paper

Topical Anaesthetics for Analgesia in Acute Corneal Abrasion: Eye Care Providers Survey

Journal and Year

Eye & Contact Lens. April 2023.

Lead Author

Catherine Anderson-Quinones

Background

• As we covered back in March 2021, take home tetracaine is probably safe, and its probably what we would all treat ourselves with if we had a corneal abrasion.
• We were always taught not to give it to patients for fear of eye-ball melting consequences (based of some studies of some poor rabbits a long time ago)
• Really the practical concern is that local anaesthetic is going to dampen corneal reflex and could lead to drier eyes not healing as well, or the patient may not notice worsening symptoms.
• So do our eye-dentist colleagues feel the same as we do or are we all just cowboys for even considering this?

Study Design

• A three question, 5 point, Likert survey was sent to ophthalmologists (most of whom had done a cornea fellowship) and optometrists worldwide

Outcomes

• They asked, assuming an uncomplicated <48h presentation of corneal abrasion its ok to give 5ml (around 100 drops) take home tetracaine:
  1. If only examined by ED
  2. If patient examined by them
  3. If the they had an abrasion themselves

Summary of Results

• 486 responses: 47% docs, 53% optometrists

• 92% were in the US. Majority of the remaining 8% were UK and Canada.

• Most respondents didn’t support 24h take home tetracaine at all:

  • Just ED examined: 98% said no
  • If they examined themselves: 97% said no
  • If they had an abrasion themselves: 89% said no

• Ophthalmologists with <10 years experience were less likely to support us in ED giving 24h take home tetracaine.

• Optometrists less likely that ophthalmologists if examined patient themselves

Authors Conclusion

Amongst their conclusions:

When asked about self-treatment for abrasion, 22.6% of respondents were more likely to use topical anaesthetics on themselves when they were the patient compared to when treating others, showing that the dogma regarding its use is not absolute.

Clinical Bottom Line

Even the paper that they reference in this study regarding all the possible nasty side effects of TA treatment concludes “Overall, topical anaesthetics post minimal risk when used in a clinically controlled setting” as a lot of the nasty examples given were a consequence of abuse of the anaesthetic agent for whatever reason. In addition they suggest that some previous animal based studies were performed using preservative-containing topic anaesthetics, where the preservatives may, in fact, have been the offending agent.

If it was me, I’d use them. So why shouldn’t that be good enough for my patients? (Assuming sensible patient, uncomplicated injury, no pre-existing eye problems, etc etc)

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