The Clinical Features of Otitis Media with Antineutrophil Cytoplasmic Antibody-Associated Vasculitis and the Role of Routine Blood Tests in Its Diagnosis.

Background: To study the clinical features of otitis media with anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (OMAAV) and its differences with other forms of ANCA-associated vasculitis (non-OMAAV) and to explore whether routine blood tests could be beneficial to diagnosing OMAAV.

Methods: A retrospective study was conducted on 18 patients with OMAAV, 15 patients with non-OMAAV, and 23 patients with otitis media with effusion (OME). Basic and clinical information, laboratory data, and treatment outcomes were collected. The differences in the clinical characteristics between OMAAV and non-OMAAV patients were explored. Furthermore, the red cell distribution width (RDW), mean platelet volume (MPV), platelet-to-lymphocyte ratio (PLR), and neutrophil-to-lymphocyte ratio (NLR) were compared between OME and OMAAV patients. The optimal cutoff values for the routine blood indicators were estimated via receiver operating characteristic (ROC) curve analysis.

Results: All eighteen OMAAV patients (100%) were initially misdiagnosed. Compared with non-OMAAV patients, involvement of nose, throat, and facial nerve was more common in OMAAV patients, whereas kidney damage was less common. However, neither of these differences was statistically significant. Relapse and disease-related death rates did not differ between the OMAAV and non-OMAAV groups. OMAAV patients presented with a lower MPV but a higher PLR and NLR than OME patients (P < 0.05).

Conclusion: OMAAV is often misdiagnosed as OME in elderly patients, but unlike OME, OMAAV is characterized by mixed hearing loss over its course. Low-cost routine blood tests may help otolaryngologists distinguish OMAAV from OME in the early stage. An abnormal middle ear condition with mixed hearing loss and a PLR ≥ 203.3 or NLR ≥ 4.7 may suggest a potential OMAAV diagnosis.