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    Patent Pending

    HINTS for Stroke in Acute Vestibular Syndrome

    Identifies potential stroke in patients with acute vestibular syndrome (AVS).
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    INSTRUCTIONS

    Proper administration of the test itself is critical to using this calculator. See a video from the authors here.

    When to Use
    Pearls/Pitfalls
    Why Use

    Only use in patients with continuous vertigo. Do not use in patients with episodic vertigo (e.g. benign paroxysmal positional vertigo) or whose dizziness has resolved by the time of assessment.

    • Requires some specialized experience to perform, and sensitivity is reduced in non-neuro-ophthalmologists (Kerber 2015). Ruling out stroke in patients with a moderate or high pre-test probability may not be possible by non-specialists.

    • Acute (<24-48 hours) MRI has lower sensitivity for posterior fossa ischemia than HINTS, assuming scoring by a specialist (Kattah 2009). In non-expert hands, consideration of the patient’s overall vascular risk (e.g. ABCD² Score) improves the sensitivity of the assessment. Delayed or repeat MRI (>48 hours) may be useful in ambiguous cases.

    • Ischemia in the territory of the anterior inferior cerebellar artery can mimic a peripheral etiology and should be kept in the differential when the HINTS localizes to the periphery but the patient has vascular risk factors, experiences sudden onset of symptoms, and/or has associated ipsilateral hearing loss.

    • AVS is a common presentation to EDs, outpatient clinics, and inpatient services. Differentiation between central and peripheral etiologies is important in narrowing the differential diagnosis and facilitate emergent therapies.

    • Acute MRI (<24-48 hours) may initially be falsely negative due to lower resolution in the posterior fossa in this time window, and so a “normal” MRI in this population cannot be relied upon to provide complete reassurance.

    Abnormal
    Normal/untestable
    Direction-fixed horizontal nystagmus
    Direction-changing horizontal/untestable nystagmus
    Absent skew deviation
    Present/untestable skew deviation

    Result:

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    Next Steps
    Evidence
    Creator Insights

    Advice

    • A “benign” HINTS examination, in the absence of other neurological deficits, suggests a peripheral localization, and investigation and management can be directed at this possibility.

    • A “dangerous” HINTs examination strongly supports a central lesion, and appropriate workup is required.

    • An important exception is that acute ischemia of the anterior inferior cerebellar artery territory can produce a “benign” HINTS examination. This possibility should be considered in patients with vascular risk factors, sudden-onset symptoms, or concurrent ipsilateral hearing loss.

    Management

    • Consider neurologist, neuro-ophthalmologist, or neuro-otologist consultation in the disposition of AVS patients, as even if the HINTS examination is “benign,” many peripheral lesions are amenable to time-sensitive therapy (eg. vestibular neuronitis).

    • Vestibular suppressants, such as prochlorperazine, can impede recovery and compensation of a peripheral vestibular lesion, and thus should be very rarely and sparingly used (if at all).

    • Patients with a “dangerous” HINTS examination are generally admitted for neuroimaging and appropriate directed therapies (e.g. stroke).

    Critical Actions

    HINTS does not replace a detailed history and general neurological examination, and care must be taken not to ignore other non-vestibular diagnoses (e.g. the vertiginous aura of superior temporal lobe seizures).

    About the Creator
    Dr. David E. Newman-Toker
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