Enterovirus, cytomegalovirus, and Epstein-Barr virus infection screening in idiopathic sudden sensorineural hearing loss

Sudden sensorineural hearing loss (SSNHL) is frequently classified as 'idiopathic' since the causative factor is not identified in most cases. In the present study we determined whether SSNHL is associated with common viral infections, namely enterovirus, cytomegalovirus (CMV) and Epstein-Barr virus (EBV). Between April 2004 and March 2005, we conducted a prospective cohort study on 48 unselected patients with unilateral idiopathic SSNHL. Plasma samples obtained at presentation were analyzed for the presence of enterovirus RNA by reverse-transcription polymerase chain reaction (RT-PCR). Recent occurrence of CMV and EBV infection was determined by serological tests. Among 23 men and 25 women aged 18-84 years (mean age 51.67 years), none presented with clinical symptoms of a viral infection compatible with preceding or concurrent viral infection. One patient (2.08%) had evidence of enterovirus infection by RT-PCR, 3 patients (6.25%) had EBV IgM, and none were positive for CMV IgM. The majority of SSNHL patients (91.67%) did not have evidence of any of the three common viral infections upon presentation. The present study failed to identify recent or concurrent systemic viral infections among SSNHL patients, except for a small proportion who demonstrated recent viral infection. Therefore the theory that viral infection is a factor in SSNHL pathogenesis is not supported by this study. Further studies in larger patient populations and different epidemiological settings are required in order to verify the true role of viral infections in SSNHL.