Vascular Etiology in Idiopathic Labyrinthitis: Implication of NLR and PLR and White Matter Changes

초록

Vascular mechanisms have been implicated in idiopathic acute unilateral audiovestibulopathy (iAUAV, also known as labyrinthitis), especially in older patients. We investigated the platelet-to-lymphocyte ratio (PLR), neutrophil-to-lymphocyte ratio (NLR), and white matter changes in patients with iAUAV/labyrinthitis to determine the potential vascular etiology in this disorder. We retrospectively analyzed complete blood count (CBC) data from patients aged over 50 years and diagnosed with iAUAV/labyrinthitis at a tertiary hospital in South Korea between March 2018 and June 2025. CBC data, Fazekas scores for white matter changes, video head-impulse tests (vHIT), and bithermal caloric test results were compared with those of patients with acute unilateral peripheral vestibulopathy (AUVP, i.e., vestibular neuritis [AUVP/VN]) and age- and sex-matched healthy controls. A total of 74 patients with iAUAV/labyrinthitis (mean age&#xb1; standard deviation [SD] = 68&#xb1; 9 years; 34 male), 84 with AUVP/VN (65&#xb1; 9 years; 46 male), and 58 healthy controls (68&#xb1; 10 years; 26 male) were included. Both NLR (p<0.001) and PLR (p=0.003) were higher in the iAUAV/labyrinthitis group than in the AUVP/VN or control groups. Patients with iAUAV/labyrinthitis had higher Fazekas scores than those with AUAV/VN (p=0.002). Compared to AUVP/VN, iAUAV/labyrinthitis was associated with a higher PLR (p=0.038), higher Fazekas score (p=0.011), increased VOR gain for the horizontal canal (p<0.001), and decreased VOR gain for the posterior canal (p=0.005). Elevated PLR and prominent white matter changes suggest a microvascular etiology of iAUAV/labyrinthitis in older adults. These serologic and imaging markers may complement standard neurotologic assessments in diagnosing iAUAV/labyrinthitis.

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