Idiopathic benign paroxysmal positional vertigo with persistent vertigo/dizziness sensation is associated with latent canal paresis, endolymphatic hydrops, and osteoporosis

Abstract Objective The aim of the present study was to examine the association of neuro-otological examination, blood test, and scoring questionnaire data with treatment-resistant intractability in idiopathic benign paroxysmal positional vertigo (BPPV) patients. Methods We experienced 1520 successive vertigo/dizziness patients at the Vertigo/Dizziness Center in Nara Medical University during May 2014 to April 2018. Six hundred and eleven patients were diagnosed as BPPV (611/1520; 40.2%) according to the diagnostic guideline of the International Classification of Vestibular Disorder in 2015. Among BPPV patients, there were 201 intractable patients (201/611; 32.9%), 66 of whom were idiopathic and enrolled to be hospitalized and receive neuro-otological examinations, including the caloric test (C-test), vestibular evoked cervical myogenic potentials (cVEMP), subjective visual vertical (SVV), glycerol test (G-test), electrocochleogram (ECoG), inner ear magnetic resonance imaging (ieMRI), blood tests including anti-diuretic hormone (ADH) and bone alkaline phosphatase (BAP), and self-rating questionnaires of depression score (SDS). Sixty-six patients were diagnosed as horizontal type cupula (hBPPVcu; n = 30), horizontal type canal (hBPPVca; n = 10), posterior type (n = 20), and probable and/or atypical BPPV (n = 6). Data are presented as ratios (+) of the number of idiopathic BPPV patients with examination and questionnaire data outside of the normal range. Results The ratio (+) data were as follows: C-test = 21.2% (14/66), cVEMP = 24.2% (16/66), SVV = 48.5% (32/66), G-test = 18.2% (12/66), ECoG = 18.2% (12/66), ieMRI = 12.1% (8/66), ADH = 9.1% (6/66), BAP = 13.6% (9/66), and SDS = 37.9% (25/66). Multivariate regression analysis revealed that the periods of persistent vertigo/dizziness were significantly longer in BPPV patients with hBPPVcu, C-test (+), endolymphatic hydrops (+), and BAP (+) compared with those with negative findings. Conclusion Although patients with idiopathic BPPV are usually treatable and curable within 1 month, the presence of hBPPVcu, canal paresis, endolymphatic hydrops, and elevated BAP may make the disease intractable, and thus require additional treatments.