Differentiating ‘benign’ from ‘dangerous’ vertigo/dizziness

10 Dec

First off – “dizziness” as a symptom is a bit of a mess. We can’t blame the patients for that but we must be clear that we’re not entirely sure what it means when a patient tells us they’re dizzy.

Next, you may well be better spending your time reading this article than my brief, bastardized summary of it.

Tarnutzer AA, Berkowitz AL, Robinson KA, Hsieh Y-H, Newman-Toker DE. Does my dizzy patient have a stroke? A systematic review of bedside diagnosis in acute vestibular syndrome. CMAJ 2011 Jun.;183(9):E571–92. PMC3114934

I found it via the wonderful R&R in the fast lane project where the esteemed Dr Weingart had recommended it.

I shall try and be brief.

So what’s useful for differentiating a central, serious cause of vertigo (about 85% vascular and 10% demyelination) from a benign, peripheral one (mainly vestibular neuritis, meniere’s etc…)?

Suggesting Stroke:

  • multiple prodromes
  • recent trauma (ie think dissection)
  • any “hard” neurological signs like cranial nerve palsies etc…
  • a normal head impulse test strongly suggests stroke [Link goes to video]
Suggesting benign:
  • gradual onset as opposed to sudden
  • a negative HINTS test [Link goes to video]

In brief, nystagmus towards the side of the gaze suggests badness.

There are lots of others but I wanted to keep it brief.

The two videos linked to above are in the appendix of the article along with some others. They were both new to me. Dix-Hallpike was the only real test I used to use for this thing and the article doesn’t see it having much of a role in differentiating.  I think it’s gonna take me a bit of practice to get good at this stuff as I find nystgamus pretty difficult in general.

When I get a bit of time I’ll try and put something together on the neuroanatomy of all this as it might be useful to understand what’s going on.

UPDATE

Patrick Linehan has made some great points in the comment below so I’ve added them on in here so you all get to read them.

A few comments on that paper:

1) The authors (who work at a tertiary referral centre) had to MAKE UP a case with a good outcome to show utility of the HINTS test, which means they have never actually seen it be useful in emergency practice! (Note that the fact that they made up the case is not mentioned in their case report, but only in the caption of the MRI under the case report!)

2) The study that showed excellent sensitivity and specificity of the HINTS test was study of 121 referred patients (half referred from the ED and half from other hospitals) that had a 75% prevalence of stroke. This means that the ED physicians already had a strong suspicion that the patients had a stroke. If you think that the patient you see in the ED with dizziness has a 75% chance of stroke, are you going to skip referring them to a neurologist or working them up further based on this test?

3) The paper deals only with people who have acute vestibular syndrome (continuous dizziness for 24 hours) so the Dix-Hallpike is not useful in their population, as BPPV is not continuous.

8 Replies to “Differentiating ‘benign’ from ‘dangerous’ vertigo/dizziness

  1. A few comments on that paper:

    1) The authors (who work at a tertiary referral centre) had to MAKE UP a case with a good outcome to show utility of the HINTS test, which means they have never actually seen it be useful in emergency practice! (Note that the fact that they made up the case is not mentioned in their case report, but only in the caption of the MRI under the case report!)

    2) The study that showed excellent sensitivity and specificity of the HINTS test was study of 121 referred patients (half referred from the ED and half from other hospitals) that had a 75% prevalence of stroke. This means that the ED physicians already had a strong suspicion that the patients had a stroke. If you think that the patient you see in the ED with dizziness has a 75% chance of stroke, are you going to skip referring them to a neurologist or working them up further based on this test?

    3) The paper deals only with people who have acute vestibular syndrome (continuous dizziness for 24 hours) so the Dix-Hallpike is not useful in their population, as BPPV is not continuous.

    • Great points patrick,

      It does seem kind of a super specialty thing – like you’d almost need someone with a sub-specialty in neuro-otology to do these tests in any reliable form. Inter-observer variability would be interesting to look at.

      If you don’t mind I’ll add your comments to the bottom of the post.

      Andy

  2. Hi,
    Thanks you for PL’s good comments.
    Is there a way to repair the link to head impulse test so that it can be shown to juniors ?

  3. By the way, it is quite clear the case is made up without trying to conceal it: “an example of such an MRI is shown in Figure 2”

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