Some HINTS on vertigo

A 76yo man presents to ED with 2 days of continual vertigo.  He feels unsteady and generally unwell, but denies any weakness, fever or headache. The vertigo was present upon waking 2 days ago and has not remitted since. It is more noticeable when he gets up to mobilise.

Is this peripheral or central?

The differentiation of peripheral and central causes of vertigo is based on history and examination findings including onset, duration, aggravating and relieving factors, nystagmus, gait and the wonderful Dix-Hallpike manoeuvre.

The comparison table tends to read something like this:

Peripheral Central
Onset Sudden Sudden or slow
Severity Intense spinning Ill defined, less intense
Pattern Paroxysmal, intermittent Constant
Aggravated by position/movement Yes Variable
Nausea/diaphoresis Frequent Variable
Nystagmus Horizontal Vertical or multidirectional
Fatigue of symptoms/signs Yes No
Hearing loss/tinnitus May occur Does not occur
Abnormal tympanic membrane May occur Does not occur
CNS symptoms/signs Absent Usually present

Rosen's provide this diagnostic algorithm (Figure 19-2):


RosenVertigoAlgorithm

Enter the HINTS examination

The HINTS examination is proposed as a method to elicit enough information to differentiate peripheral and central causes of constant vertigo (eg vestibular neuronitis vs cerebellar stroke) in a 3-test examination:

  • Head Impulse testing
  • Nystagmus
  • Test of Skew

The HINTS study was published in 2009, describing 101 patients assessed by neurologists after referral for acute vestibular syndrome (vertigo, nystagmus, nausea/vomiting, head-motion intolerance, unsteady gait) in the presence of ≥1 stroke risk factor. These 3 examinations were found to have a sensitivity of 100% and specificity of 96% for a central lesion using diffusion-weighted imaging MRI at up to 48 hours as the gold standard. In fact, this combination of examination findings was more sensitive than MRI at presentation, which was falsely negative in 8 patients with an ischaemic stroke (and detected on MRI up to 3 days later).

Obviously, this study was set in a group of high-risk patients with a high incidence of central causes. The clinical examination was done by neurologists, and there was no blinding of results.

So how do I do it?

In the data supplement of the HINTS study, you'll find videos of each examination technique used, or you can see all of them in one video by one of the authors, David Newman-Toker.

The nice people at EMJ club have collated videos on youtube demonstrating the normal and abnormal findings in central and peripheral vertigo.

Is there other evidence?

There is no evidence for use of HINTS in the undifferentiated ED setting.

An upcoming systematic review in the Annals of Emergency Medicine looking at the accuracy of HINTS identified only 3 studies on HINTS and 1 more that included all of the examination tests.

One recent study compared HINTS to traditional evaluation for stroke risk with ABCD2, showing HINTS to be more sensitive for detecting a central cause than both ABCD2 score and early MRI: Newman-Toker et al, HINTS outperforms ABCD2 to screen for stroke in acute continuous vertigo and dizziness. Acad Emerg Med. 2013 Oct;20(10):986-96

This study drew some criticism for using the ABCD2 score, which was derived to predict stroke risk after TIA, and for patient selection (190 patients with acute, persistent vertigo with nystagmus plus nausea/vomiting, head motion intolerance, and new gait unsteadiness—findings that are sufficient to, and for all these patients, did, justify hospitalisation from the ED). The proportion with posterior fossa stroke (59.5%) or other central causes (5.8%) was very high, whereas the proportion of unselected dizziness patients with stroke or TIA is 3.2%.

The authors of the HINTS trial have also published a systematic review of bedside diagnostic tests. No surprises that they support the use of HINTS: Tarnutzer et al, Does my dizzy patient have a stroke? A systematic review of bedside diagnosis in acute vestibular syndrome CMAJ. Jun 14, 2011; 183(9): E571–E592 also available summarised into a PV card

So should we be using HINTS?

Despite the lack of evidence for its use in the undifferentiated ED population, there is probably still a role in helping us better examine vertiginous patients and diagnose central causes in combination with our usual stellar history-taking and neurological examining. The examination itself should only take minutes, and provides valuable information (assuming we know how to do and interpret it) that we won't pick up in a standard ED screening neuro exam.

Maybe someone would like to look into HINTS in ED further (the HINTED trial)? A 4.10 project, perhaps?

Please add in your comments below with your opinion.

 

Further Reading:

Excellent review on peripheral vs central vertigo with explanations of the examination techniques and findings: Nelson & Viire The Clinical Differentiation of Cerebellar Infarction from Common Vertigo Syndromes West J Emerg Med. 2009;10(4):273-277

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