What is your diagnostic approach to the acutely vertiginous patient?
The bottom-line question is: Is the cause peripheral or central in etiology?
In this great 2011 systematic review article in CMAJ on Acute Vestibular Syndrome (AVS), the authors review how (un)predictive elements of the history and physical exam are. By definition of AVS, symptoms must be continuous for at least 24 hours and have no focal neurologic deficits.
Frighteningly, the authors report many of the signs and symptoms (type of dizziness, hearing loss, patterns of nystagmus, Hallpike-Dix) are not as predictive as we classically are taught!
The take home point is to learn and incorporate the 3-part HINTS exam into your diagnostic approach (see bottom box on card). It is reported to be as good as a diffusion-weighted MRI for diagnosing a posterior stroke. The steps are:
- Do the horizontal head impulse test. (Normal = central cause)
- Check for directionally-alternating nystagmus movement on left and right gaze.
- Do the alternate cover test.
Adapted from 1
Go to the ALiEM Cards site for more resources.
There is a helpful 10-minute video showing normal and abnormal HINT findings:
- Head impulse testing
- Nystagmus testing
- Testing of skew
VIDEO LINK: http://emcrit.org/misc/posterior-stroke-video/
Thanks to Dr. Brian Resler (UCSF-SFGH EM resident) for giving me the heads up about this at Followup Conference!