Perspectives on the Pathophysiology and Treatment of Sudden Idiopathic Sensorineural Hearing Loss

Background: Sudden, idiopathic sensorineural hearing loss is an acute dysfunction of the inner ear whose cause cannot be determined with the currently available methods of clinical diagnosis.Methods: This continuous medical education article is based on a selective review of the literature and on the revised S2 guidelines for acute sensorineural hearing loss of the Association of the Scientific Medical Societies in Germany (AWMF), which were issued on 28 January 2009.Results: Recent surveys in Germany suggest that the incidence of sudden, idiopathic sensorineural hearing loss may be as high as 300 per 100 000 persons per year.To distinguish this entity from acute hearing loss of other causes, special tests are necessary, including ear microscopy, pure-tone audiometry, and acoustic evoked response audiometry.No clinical trial of the highest evidence level has yet been published to document the efficacy of any type of treatment for sudden, idiopathic sensorineural hearing loss.Nonetheless, there is evidence from trials with lower levels of evidence, post-hoc analyses, and assessments of secondary endpoints of clinical trials indicating that plasma-expander therapy, the systemic and local (intratympanic) administration of cortisone, and the reduction of acutely elevated plasma fibrinogen levels may be beneficial. Conclusion:Further clinical trials are needed to validate these preliminary results.Until clear data are available, the predicted benefit and risk of any proposed treatment for sudden, idiopathic sensorineural hearing loss should be discussed in detail with the patient before the treatment is begun.