Moving from H.I.N.T.S. to H.I.N.T.S. PLUS in the Management of Acute Vestibular Syndrome

Dear Editor

Acute vestibular syndrome (AVS) is defined by a rapid onset and persistent vertigo or dizziness (lasting more than 24 hours) accompanied by nausea/vomiting, nystagmus, and head motion intolerance.^1-4

Acute vestibular syndrome is responsible for almost 20% of dizzy patients presenting to the emergency department. ⁵ There are 2 main causes of AVS. Vestibular neuritis, which is the most common, and vertebrobasilar stroke, which can be life-threatening.^1,2,5 In the latter, the diagnosis can be challenging because more than 50% of patients presenting with vertigo do not exhibit associated focal or general neurologic signs. ¹

H.I.N.T.S. (Head-Impulse-Test – Nystagmus – Test-of-skew) is a three-step bedside oculomotor exam used to differentiate peripheral from central causes in AVS. ¹ This test can identify a stroke with a sensitivity of 96.5% and a specificity of 84.4%. ⁵ More importantly, H.I.N.T.S. has also shown a superior level of sensitivity compared to diffusion-weighted cerebral magnetic resonance imaging (MRI) in the first 48 to 72 hours of symptoms onset. ¹

However, we recently managed in our vertigo clinic a patient with a left labyrinthine infarction confirmed on MRI. He had an AVS with sudden moderate left sensorineural hearing loss, right horizonto-rotatory nystagmus, abnormal left head impulse test, and negative test of skew, suggesting a peripheral etiology. He also presented a left latero-deviation at Fukuda maneuver and had no other neurological sign.

Labyrinthine infarction is a rare cause of AVS induced by an infarction in the territory of the AICA whose internal auditory artery generally comes.^6,7 In this situation, the H.I.N.T.S. can misdirect the diagnosis toward a peripheral vestibular disorder. ⁸ Indeed, the Head-Impulse-Test would be pathologic although the disorder comes from a central origin.

In 2013, H.I.N.T.S PLUS hearing loss due to cochlear or brainstem ischemia was introduced as a new sign that could increase diagnostic accuracy of AVS. ⁵

As suggested by some authors, we recommend using the H.I.N.T.S PLUS instead of the H.I.N.T.S. in the management of AVS in order not to miss a labyrinthine infarction.