Emergency assessment of vertigo using CT optic nerve sheath diameter: A novel approach to etiology differentiation and prognosis

Abstract

Background: Differentiating central from peripheral vertigo in the emergency department (ED) remains a major diagnostic challenge, as early clinical findings frequently overlap. Computed tomography (CT) is widely used for initial imaging but has limited sensitivity for posterior fossa lesions. Measurement of the optic nerve sheath diameter (ONSD) on CT has emerged as a promising surrogate marker of intracranial pressure (ICP), yet its utility in vertigo patients has not been fully elucidated.

Methods: We retrospectively analyzed 294 adult patients who presented to a tertiary ED with acute vertigo between January 2022 and December 2023. Patients were classified as central (n=119) or peripheral (n=175) vertigo based on clinical and radiological findings. ONSD was measured bilaterally at 3 mm behind the globe on axial CT images. Comparisons between groups and subgroups were performed using independent samples t-test, one-way ANOVA with Bonferroni post-hoc test, and Chi-square analysis. Associations with hospitalization and mortality were also assessed.

Results: Mean ONSD values were significantly higher in central vertigo (5.13 ± 0.68 mm) than in peripheral vertigo (4.81 ± 0.41 mm, p<0.001). Among central subgroups, patients with infarction (5.18 ± 0.63 mm) and hemorrhage (5.22 ± 0.82 mm) exhibited increased diameters, whereas those with cerebellar masses demonstrated lower ONSD (4.62 ± 0.65 mm), closer to peripheral values. Right-sided lesions produced the largest diameters (5.27 ± 0.64 mm), followed by left-sided (5.00 ± 0.72 mm) and no lesion (4.81 ± 0.42 mm) groups (p<0.001). Hospitalized patients had higher ONSD (5.12 ± 0.67 mm) compared to discharged patients (4.80 ± 0.41 mm, p<0.001). Mortality cases (n=5) displayed markedly elevated values (6.24 ± 1.04 mm) versus survivors (4.92 ± 0.52 mm, p<0.001).

Conclusions: CT-derived ONSD is a valuable adjunct for differentiating central from peripheral vertigo and may predict hospitalization and mortality. Importantly, cerebellar masses exhibited distinct ONSD behavior compared to acute vascular lesions, underscoring the need to consider pathophysiological heterogeneity in interpretation. Integration of ONSD into ED protocols may enhance risk stratification and clinical decision-making.