Acute Vestibular Syndrome (AVS) 12/5/2017

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1 Sharon Hartman Polensek, MD, PhD Dept of Neurology, Emory University Atlanta VA Medical Center DIAGNOSTIC GROUPS FOR PATIENTS PRESENTING WITH DIZZINESS TO EMERGENCY DEPARTMENTS Infectious 2.9% Genitourinary 5.1% Digestive Psychiatric 7.0% 7.2% Injury/Poisoning Metabolic 10.6% 11.0% Cerebrovascular 4.0% Neurologic (all) Respiratory 11.2% 11.5% Cardiovascular 21.1% Otologic/Vestibular 32.9% 0.0% 5.0% 10.0% 15.0% 20.0% 25.0% 30.0% 35.0% From Newman-Toker et al, 2008, Mayo Clin Proc Acute Vestibular Syndrome (AVS) Onset of dizziness or vertigo that develops over seconds or hours Associated with nausea, gait instability and head motion intolerance Nystagmus on exam Persists for > 24 hours 1

2 Initial Approach to Patient Important historical features Description of dizziness: Vertigo, lightheadedness, or other Time of onset, duration of spell, provoking factors, e.g., movement If vertigo lasts several minutes in the elderly or in a patient with vascular risk factors, have low threshold for obtaining CTA, MRA or conventional angiogram (Kim and Lee, 2013). Assess whether vestibulopathy likely is peripheral or central on the basis of history and exam findings Spontaneous Nystagmus Associated with Peripheral Vestibulopathy More intense when the patient looks in the direction of the quick-phase than in the slow-phase direction Jerk nystagmus that beats away from the side of the lesion Follows Alexander s Law 2

3 Nystagmus due to a peripheral vestibular lesion typically is suppressed by visual fixation. Frenzel lenses Infrared goggle system Direct ophthalmoscopy while covering other eye Effect of Visual Fixation on Nystagmus due to Peripheral Vestibulopathy Click to add text From Abnormal Vestibular Ocular Reflex (VOR) Associated with Peripheral Vestibulopathy Can test for this with Head Impulse Test Also known as head thrust test Tests the ear that the head is being moved toward Can be performed by either moving head from the midline to lateral position or by moving head from the lateral position to midline Schubert M C et al.,

4 Head Impulse Test Head Impulse Test (HIT) If abnormal, test is considered positive When patient s head is pitched forward 30 degrees and head is moved unpredictably (Schubert et al., 2004) Sensitivity for identifying bilateral vestibular weakness = 84% Specificity = 82% 10% of posterior circulation strokes have positive HIT, usually pontocerebellar/labyrinthine & inferior cerebellar Covert saccades may be missed Video HIT more sensitive test in identifying vestibular weakness in patients with isolated covert saccades Management of Vestibular Neuritis (Strupp et al., NEJM 2004) Methylprednisolone significantly improves the recovery of peripheral vestibular function, whereas valacyclovir does not. 4

5 Signs of Central Vestibular Dysfunction Vertical nystagmus in primary position Severe postural instability with falling Other neurological signs (e.g., long tract signs, abnormal cranial nerve exam) Gaze-evoked nystagmus Assessment of Gaze-holding Ask patient to maintain horizontal and vertical positions of gaze (30 degrees off center) Minimal drift = normal Horizontal gaze-evoked nystagmus lesions within cerebellar flocculus or vestibular nucleus Brun s nystagmus - (cerebellopontine angle lesion) asymmetric large-amplitude gaze-evoked nystagmus evoked when gazing to the side of the lesion physiological nystagmus usually disappears after target is brought back into view of both eyes 5

6 From Skew Deviation Vertical misalignment of eyes that cannot be explained by an EOM palsy Can be distinguished from EOM palsy in that degree of misalignment changes little with different directions of gaze Due to lesion somewhere in VOR reflex pathway Test of Skew -- _embedded&v=-j170k7vada Bedside Exam Protocol for AVS -- HINTS = Head Impulse, Nystagmus, Test of Skew Head Impulse Test, and Search for: Direction-changing nystagmus in eccentric gaze, or Skew deviation (vertical ocular misalignment) HINTS more sensitive for stroke than early MRI in acute vestibular syndrome Kattah et al.,

7 Vertigo and Stroke 2.5% of emergency department presentations are for vertigo (Kerber et al., 2008) ~ 20% of ischemic events occur in the posterior circulation Most common symptom of vertebrobasilar disease is dizziness (Savitz and Caplan, 2005). Less than 1% of isolated vertigo is due to a stroke (Kerber et al., 2006) Inferior cerebellar and small brainstem infarctions are increasingly recognized as a cause of isolated vertigo (Chang and Wu, 2010) Acute combined auditory and vestibular loss may herald impending anterior inferior cerebellar artery (AICA) stroke. Vertebrobasilar Disease <1% of patients with VBI had only a single presenting symptom or sign (Caplan et al., 2004) Vertigo frequently accompanied by hypotonia of arm, nystagmus, cranial nerve deficits, gait difficulty Vertebral artery stenosis may have brief TIAs w/dizziness, difficulty focusing, and imbalance in situations that reduce blood pressure or blood flow Cardinal symptom in vertebral artery dissection is pain (posterior neck, occiput, shoulders) Positional Testing Evaluate for central positional nystagmus Evaluate for benign paroxysmal positional vertigo (BPPV) Evaluate for dizzy symptoms associated with normal eye movements 7

8 Testing for Positional Nystagmus Useful in Diagnosis of Acute Vestibular Migraine Hartman and Tusa, Percent Spontaneous Headshaking Positional Stimuli Which Provoked Nystagmus Vestibular Migraine May Mimic Stroke From Nystagmus typically sustained May be horizontal, vertical or torsional May change in direction during exam Migraine Dizziness duration minutes to days +/- headache Sxs worsen with movement May be accompanied by motion sensitivity and anxiety (frequent triad) Head impulse test typically negative 8

9 Benign Paroxysmal Positional Vertigo (BPPV) One of the most common causes of dizziness 17% of dizzy patients had BPPV (Nedzelski et al., 1988) 10 25% of head trauma patients develop BPPV (Proctor et al., 1956; Barber, 1964; Davies & Luxon, 1995) Diagnosed with Dix-Hallpike or side-lying maneuver Treated with canalith repositioning maneuver (CRM) From Patient symptoms - BPPV Brief vertigo on the order of seconds associated with head movement Asymptomatic if head is stationary Triggers are rolling over, looking up, raising up from a supine position, leaning forward (dentist, shower, beauty parlor) Multiple episodes per day Can sometimes tell which side to avoid Mild imbalance Dix-Hallpike Test for posterior canal BPPV Nystagmus - Upbeating and torsional Nystagmus beats toward affected ear (which is down) for less than 60 secs; usually less than 30 secs Latency, incr. in amplitude then decrease May reverse upon returning to seating position fatigability From 9

10 Alternative to Dix-Hallpike Test for Posterior Canal BPPV Side-lying is a valid alternative test to the Dix-Hallpike maneuver, which could be useful when range-ofmotion limitations or other problems preclude use of the Dix-Hallpike maneuver (Cohen, 2004). Characteristic Nystagmus for Posterior BPPV From Horizontal BPPV Nystagmus Can be confused with central positional nystagmus, suggestive of central lesion Note crescendo-decrescendo tempo of nystagmus Nystagmus self-limited; not sustained like typical central positional nystagmus From 10

11 Summary Evaluate for central signs HINTS, vertical nystagmus, nystagmus not blocked by visual fixation Evaluate for vestibular nerve weakness Head impulse test is positive Spontaneous nystagmus follows Alexander s Law Blocked or diminished by visual fixation Check for BPPV and treat with CRM if possible Consider referral Robot cerebellar 11

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