Sensory hearing loss in children with Mumps infection

Mumps infection is endemic in Iran and mumps parotiditis is a common disease in Iranian children. There has been a dramatic decrease in the worldwide incidence of mumps since the introduction and use in 1968 of the very effective and inexpensive mumps vaccine. In Iran probably due to a higher percentage of unvaccinated young persons <15yr, the incidence rate of mumps infection and its sequel are higher in comparison to corresponding data from developed countries prior to comprehensive vaccination programs. The aim of the study was to investigate the effects of the mumps virus on cochlear function and to determine the frequency of related Sensory Neural Hearing Loss (SNHL) in children. This descriptive case-series study was conducted in 94children, aged less than 14 years, hospitalized between 1999 and 2001, in the pediatric ward of the Hazrat Rasool Hospital in Tehran. All patients with documented mumps infection (specific mumps-IgM antibody) were evaluated twice for audiometeric function on the basis of diagnostic parameters for sensory neural hearing loss; the first evaluation was done on admission and the second three weeks later. 54 patients (age range 1-14y, mean age 4.83±3.93, male: female ratio30:24) were studied in two years. The highest incidence of mumps was seen in winter (37%) and spring (28%) and the lowest in summer (13%). Specific IgM antibody for mumps virus was detected in 74 children. Comprehensive audiologic evaluation was done in 54 patients at admission and again 3 weeks later. SNHL was detected in 7.2% of patients; the 4.4% incidence of SNHL in this study was higher than in other studies in developed countries prior to comprehensive vaccination programs. Implementation of comprehensive vaccination programs in young Iranians could dramatically reduce the burden and costs imposed by the infection and its sequelae.