Hints for Stroke?

Original research article: Krishnan, Kailash, Kerolos Bassilious, Erik Eriksen, Philip M Bath, Nikola Sprigg, Sigrun Kierulf Brækken, Hege Ihle-Hansen, Morten Andreas Horn, and Else Charlotte Sandset. “Posterior Circulation Stroke Diagnosis Using HINTS in Patients Presenting with Acute Vestibular Syndrome: A Systematic Review.” European Stroke Journal, (April 2019). doi:10.1177/2396987319843701. https://doi.org/10.1177/2396987319843701

HINTS for stroke?

Comment by Linxin Li

Acute vestibular syndrome (AVS) is common and is often considered benign, but it is estimated that up to one in four patients presenting with AVS could be suffering from posterior circulation strokes.¹ Given that brain scans, even MRI brain, can have low sensitivity in the posterior fossa, bedside predictors remain essential to differentiate central vs. peripheral vestibulopathies.

In this issue of ESJ, Krishnan and colleagues reported a systematic review looking at the sensitivity and specificity of a quick bedside test in identifying posterior circulation stroke in patients presenting with AVS – the Head Impulse-Nystagmus-Test of Skew (HINTS) test.²

HINTS was first described in 2009 and is a 3-step oculomotor examination. A positive HINTS test includes the presence of any of the three signs: a normal horizontal head impulse test, direction-changing nystagmus in eccentric gaze and eye skew deviation.¹

In this systematic review, 6 studies involving 644 patients were included (mean age 58 years). All patients were evaluated in emergency departments and MRI brain with diffusion-weighted imaging was used in all studies as the gold diagnostic standard. The pooled sensitivity and specificity using HINTS to identify any stroke was 95.5% and 71.2% respectively. The overall positive predictive value was 59.9% and negative predictive value was 97.2%. Of interest, among those with an imaging proven infarct, the most common site was the cerebellum followed by the pons.

Whilst the authors confirms that HINTS appears to be a reliable and effective bedside test in differentiating acute posterior circulation stroke from peripheral vestibular causes in patients presenting with AVS, several questions remain. Firstly, the feasibility of performing the full HINTS in acutely unwell patients, especially in patients at older ages, is unclear and whether a simplified version of HINTS could be adopted in sick patients is yet to be determined. For example, skew was shown to predict brainstem involvement in AVS even when an abnormal horizontal head impulse test falsely suggested a peripheral cause.¹ Secondly, the reproducibility of HINTS between specialists versus non-specialists needs to be further validated. Lastly, although HINTS can be useful in managing patients presenting with persistent AVS, comprehensive clinical judgement remains crucial in the hyper-acute phase.

The full paper can be found at: https://doi.org/10.1177/2396987319843701

 Reference

1. Kattah JC, Talkad AV, Wang DZ, et al. HINTS to diagnose stroke in the AVS: three-step bedside oculomotor examination more sensitive than early MRI diffusion-weighted imaging. Stroke 2009; 40: 3504-10.
2. Krishnan K, Bassilious K, Eriksen E, et al. Posterior circulation stroke diagnosis using HINTS in patients presenting with acute vestibular syndrome: a systematic review. European Stroke Journal 2019. DOI: 10.1177/2396987319843701