Hearing loss during bacterial meningitis.

To determine the natural history and pathogenesis of hearing loss in children with acute bacterial meningitis. Multicentre prospective study. 21 hospitals in the south and west of England and South Wales. 124 children between the ages of 4 weeks and 16 years with newly diagnosed bacterial meningitis. Children underwent repeated audiological assessment with the first tests being performed within six hours of diagnosis. By using a combination of otoacoustic emissions, auditory brainstem responses, and tympanometry the differences between cochlear, neural, and conductive defects were distinguished. Ninety two children (74%) had meningococcal and 18 (15%) had pneumococcal meningitis. All cases of hearing loss were apparent at the time of the first assessment. Three children (2.4%, 95% confidence interval (CI) 0.5 to 6.9%) had permanent sensorineural hearing loss. Thirteen children (10.5%) had reversible hearing loss of whom nine had an impairment that resolved within 48 hours of diagnosis. It is believed that this "fleeting' hearing loss has not been reported previously. The cochlea was identified as the site of the lesion in both the permanent sensorineural and reversible impairments. Hearing loss was more common in children who had been ill for more than 24 hours (relative risk 2.72; 95% CI 0.93 to 7.98). Sensorineural hearing loss developed during the earliest stages of meningitis. Permanent deafness was rare but 10% of the patients had a rapidly reversible cochlear dysfunction. This may have progressed to permanent deafness if the patients had not been treated promptly.