Audiological evaluation in children with cumulative low-level of lead exposure
Avaliação audiológica em crianças com baixo nível de exposição cumulativa ao chumbo
Kátia de Freitas Alvarenga; Daniela de Oliveira Manoel; Fernanda Zucki; Lilian Cássia Bórnia Jacob-Corteletti; Andrea Cintra Lopes; Mariza Ribeiro Feniman
Abstract
Purpose: to verify the occurrence of sensorineural hearing loss in children with low level of cumulative lead exposure.
Methods: 156 lead-poisoned children, 94 males and 62 females, ranging in age from 18 months old to 14 years and 5 months old were subjected to analysis of longitudinal lead level in blood as well as pure tone audiometry and transient evoked otoacoustic emissions.
Results: the population studied had a mean estimated blood lead level of 12.2±5.7 µg/dL (range between 2.4 and 33 µg/dL); all children had a normal response in pure tone audiometry at 20 dBHL in the frequencies tested, 0.5, 1, 2 and 4 kHz, in both ears; the transient evoked otoacoustic emissions were presented for all frequencies bilaterally in 79 children surveyed.
Conclusion: there has been no hearing loss in children with a history of low cumulative lead exposure, as there was no injury of cochlear outer hair cells, even if subclinical.
Keywords
Resumo
Objetivo: verificar a ocorrência de perda auditiva sensorioneural em crianças com baixo nível de exposição cumulativa ao chumbo.
Métodos: 156 crianças intoxicadas por chumbo, 94 do sexo masculino e 62 do sexo feminino, na faixa etária entre 18 meses a 14 anos e 5 meses, foram submetidas a análise longitudinal do nível de plumbemia em sangue, bem como audiometria tonal liminar e emissões otoacústicas evocadas por estímulo transiente.
Resultados: a população pesquisada apresentou um valor médio de plumbemia estimada de 12,2±5,7 µg/dL (faixa entre 2,4-33 µg/dL); todas as crianças apresentaram resposta normal na audiometria tonal liminar em 20 dBNA nas frequências testadas, 0,5; 1; 2 e 4 kHz, para ambas as orelhas; as emissões otoacústicas evocadas por estímulo transiente estiveram presentes para todas as frequências bilateralmente, nas 79 crianças pesquisadas.
Conclusão: não foi constatada perda auditiva sensorioneural em crianças com histórico de baixo nível de exposição cumulativa por chumbo, assim como não foi encontrada lesão de células ciliadas externas na cóclea, mesmo que subclínicas.
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Referencias
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Submitted date:
18/10/2011
Accepted date:
05/02/2012
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