[Progressive sensorineural hearing loss: immunologic etiology]

Abstract

An auto-immune progressive sensorineural hearing loss (PSNHL) can occur as one of the clinical features of systemic immune-mediated disorders, such as Cogan's syndrome, Behçet's disease, Wegener's granulomatosis, mixed cryoglobulinaemia, systemic sclerosis, systemic lupus erythematosus, giant cell arteritis, panarteritis nodosa, relapsing polychondritis, unclassified systemic vasculitides, etc, or as a distinct clinical entity, the so-called auto-immune inner ear disease. The clinical evolution of the hearing loss during the course of the systemic disease is extremely variable (slowly progressive versus rapidly progressive), while the auto-immune inner ear disease is usually characterized by a rapidly developing (weeks or months) progressive hearing loss. In both cases a timely clinical assessment and treatment can positively affect the prognosis of the hypoacusia. To date, no laboratory test will give a sure diagnosis of autoimmune hearing loss and only a good response to corticosteroid and/or cytostatic treatment can indirectly confirm this diagnosis. The laboratory tests that are usually performed can be divided into aspecific and specific tests, the latter evaluating the immune-mediated response to the specific inner ear antigen. Evaluation of the aspecific parameters sometimes shows high values of erythrocyte sedimentation rate and C-reactive protein, but often no alteration of the inflammation parameters is observed. However, the specific tests seem to achieve higher sensibility and sensitivity but to date they are not available in clinical practice. In this study we examined a group of 13 patients affected with bilateral idiopathic PSNHL who underwent Western Blot, which is a specific test for the inner ear antigen. A positive result was found in 53.8% of the cases; in particular, all 3 patients who had an improvement of hearing loss with corticosteroid treatment, and therefore were probably suffering from auto-immune progressive hearing loss, had a positive result to the Western Blot test.