DIAGNOSIS OF ACUTE VESTIBULAR NEURITIS

Abstract

Acute vestibular neuritis (AVN), also known as acute unilateral vestibulopathy, is one of the main causes of acute vestibular syndrome (AVS). It is characterized by sudden and unilateral loss of peripheral vestibular function, usually attributed to viral inflammation of the vestibular nerve, without hearing impairment or central neurological deficits. Clinically, it manifests as intense and continuous vertigo of abrupt onset, associated with nausea, vomiting, and postural instability, with a tendency to fall to the affected side. The diagnosis is essentially clinical, based on history and a systematic bedside otoneurological examination. The main diagnostic challenge lies in the clinical overlap with posterior circulation stroke. For differentiation, the HINTS (Head Impulse, Nystagmus, Test of Skew) protocol is fundamental, based on the presence of peripheral nystagmus (horizontal-torsional and unidirectional), altered head impulse test, and absence of vertical deviation (skew). Objective tools, such as the video head impulse test (vHIT), have stood out for quantifying the vestibulo-ocular reflex (VOR) and detecting corrective saccades (which reduces examiner dependence and improves risk stratification), and their combination with HINTS can increase diagnostic accuracy. Complementary tests, such as caloric tests, can be used in atypical cases, and integration with history, neurological examination, and, when necessary, neuroimaging, is crucial for clinical management. This study consists of a narrative literature review, aiming to analyze and synthesize the most recent scientific evidence, from the last five years, related to the diagnosis of acute vestibular neuritis, highlighting diagnostic criteria, performance of clinical and instrumental tests, and their implications for care flows.