Bedside Approach to Acute Vertigo with Spontaneous Horizontal Nystagmus: The Role of Simultaneous Ice-Water Test Stimulation and Its Correlation with the HINTS Protocol in Differentiating Peripheral and Central Etiologies

BACKGROUND: Acute vertigo is among the most frequent causes of access to the Emergency Department. In acute vestibular syndrome, differentiating peripheral from central causes remains challenging. The HINTS protocol provides high diagnostic accuracy but requires expertise and adequately informed physicians. The caloric ice-water test has recently been proposed as a bedside tool to aid this differential diagnosis. This study evaluates a novel approach: simultaneous bilateral ice-water irrigation in association with the HINTS protocol. METHODS: One hundred consecutive patients presenting with acute vertigo and spontaneous unidirectional nystagmus were enrolled across three Italian centers. All patients underwent clinical assessment including among other the HINTS protocol and the simultaneous bilateral ice-water irrigation. Changes in spontaneous nystagmus during the ice test were recorded. RESULTS: Eighty-six patients fulfilled HINTS criteria for acute unilateral peripheral vestibulopathy, all of whom demonstrated marked suppression/abolition of nystagmus during the simultaneous ice test. In contrast, nystagmus persisted in all 12 patients classified as having central vestibular pathology. CONCLUSIONS: Simultaneous bilateral ice-water irrigation is a simple and well-tolerated bedside test that demonstrates strong concordance with the HINTS protocol. While it cannot replace comprehensive clinical assessment, it represents a valuable complementary tool to distinguish peripheral from central causes of acute vertigo.