Acute vestibular syndrome (AVS) is defined as the sudden onset of acute, ‘continuous’ vertigo (lasting longer than 24 hours), associated with nausea, vomiting and head motion intolerance, the term was initially introduced by Hotson and Baloh in 1998. Vestibular neuritis (VN), the most common cause of an AVS, It is also estimated that 10%-20% of dizzy patients visiting emergency departments (ED) have an AVS. The second most common cause of an AVS is an ischaemic stroke involving the cerebellum or the brainstem (probably 5%-10% of all patients with AVS). Vertigo and nystagmus ranked as the most common symptom/sign in patients with posterior circulation stroke.
Misdiagnosis of posterior fossa infarcts in emergency-care settings is frequent. A three-step bedside oculomotor exam (H.I.N.T.S.: Head-Impulse-Nystagmus-Test-of-Skew) appears more sensitive for stroke than early MRI in AVS.
This review illustrates the clinical hints of these tests and applying the diagnostic predictors in clinical practice.