Hearing loss from childhood bacterial meningitis is believed to develop early and have little tendency for recovery. We performed serial hearing evaluations in a large number of children with bacterial meningitis in Luanda, Angola to clarify if, and how often, the result changed.
Children with confirmed bacterial meningitis and hearing evaluations on admission, day 7 of treatment and the follow-up visit formed the study group. Hearing was tested by auditory brainstem response audiometry using stimuli of 40 dB, 60 dB and 80 dB. Threshold changes are described between the composite levels of 40/60 dB and 80/>80 dB.
In all, 235 ears were tested. While the ≤60 dB and ≥80 dB levels were maintained through all 3 examinations in 54% and 5% of ears, respectively, changes occurred in 41%. Deterioration from the ≤60 dB level to ≥80 dB was found in 10% of the ears transiently and in 7% permanently. Improvement from the ≥80 dB level to ≤60 dB occurred in 22% of the ears. Half of the ears with ≥80 dB impairment at the follow-up visit arrived with this finding; the others lost hearing later. Maintaining the ≤60 dB level throughout was associated with milder disease (P = 0.003), fewer convulsions (P < 0.0001) and older age (P = 0.009).
Almost half of the ears showed threshold changes after admission during recovery from bacterial meningitis, most frequently improvement of initially severely impaired hearing, but some normal ears or with moderate impairment became severely impaired.