Acute Vestibular Syndrome vs Stroke

Author: Michelle Lin, MD
Updated: 12/2/2011

Acute Vestibular Syndrome vs. Stroke

Acute Vestibular Syndrome (AVS) Symptoms

  • Acute dizziness with nausea/vomiting
  • Unsteady gait
  • Nystagmus
  • Intolerance to head motion
  • Lasts ≥24 hrs
  • No focal neurologic signs

Most Common Causes

  • Vestibular neuritis (labyrinthitis)
  • Vertebrobasilar CVA

Central Causes

  • Vertebrobasilar CVA (83%)
  • Multiple sclerosis (11%)
  • Other (6%)

Caution

  • Over 50% of patients with a vertebrobasilar CVA have no focal neurologic deficit.

Which Bedside Tests Help Differentiate Peripheral from Central Causes of AVS?

NOT helpful

  • Differentiating characteristic of dizziness (vertigo, presyncope, unsteadiness)
  • Onset of dizziness (sudden vs gradual)
  • Provocative head movement (e.g. Hallpike-Dix)
  • Proportionality of symptoms such as severity of dizziness, vomiting, gait impairment (e.g. severe gait impairment with mild dizziness does not mean central cause)
  • Hearing loss
  • Patterns and vectors of nystagmus
  • Noncontrast head CT has sensitivity of only 16% for acute ischemic CVA

Helpful

  • Multiple episodes of dizziness: Predictive of central cause (CVA)

  • Headache or neck pain: Predictive of central cause (CVA, vertebral artery dissection)

    • Positive LR = 3.2
    • Absence of pain not predictive

  • Any neurologic signs, especially truncal ataxia (unable to sit upright with arms crossed) and severe gait instability

    • Strongly predictive of central cause

  • Horizontal head impulse test (vestibular-ocular reflex)

    • If abnormal, suggests peripheral vestibular cause
    • If normal, predictive of central cause (positive LR 18.4, negative LR 0.16)

  • Gaze-evoked nystagmus (right-beating nystagmus on right gaze and left-beating nystagmus on left gaze)

    • Means dysfunction of gaze-holding structures in brainstem and cerebellum
    • If abnormal, predictive of central cause (specificity 92%, sensitivity 38%)

  • Vertical ocular misalignment on alternate cover test

    • If abnormal skew deviation, predictive of central cause (sensitivity 30%, specificity 98%)

  • Diffusion-weighted MRI

    • Good but not perfect (sensitivity 83% for ischemic CVA)

Composite HINTS Exam

HINTS = H*ead *Impulse test, N*ystagmus, *Test of Skew exam

Abnormal findings summarized using INFARCTs acronym:

  • I*mpulse *Normal
  • F*ast-phase *Alternating
  • R*efixation on *Cover Test
  • If any 1 of 3 abnormal, sensitivity 100% and specificity 96% for central cause after HINT training (Kattah et al. Stroke, 2009)

HINTS test seems as good as diffusion-weighted MRI to r/o CVA in AVS.

References

  • Kattah JC, Talkad AV, Wang DZ, Hsieh YH, Newman-Toker DE. HINTS to diagnose stroke in the acute vestibular syndrome: three-step bedside oculomotor examination more sensitive than early MRI diffusion-weighted imaging. Stroke. 2009 Nov;40(11):3504-10. [PubMed]
  • Tarnutzer AA et al. Does my dizzy patient have a stroke? A systematic review of bedside diagnosis in acute vestibular syndrome. CMAJ. 2011; 183(9): E571-592. [PubMed]