Introduction: Congenital hypothyroidism (CH) is the most common congenital endocrine disorder in childhood and is one of the most common preventable causes of mental retardation. Thyroid hormones (TH) are essential for normal development of auditory system. Deficiency of TH during fetal and early postnatal sensitive periods of ear development, results in various degree of congenital hearing impairments or even in deafness if TH substitution is not instituted within a critical time window. Hearing impairment in hypothyroidism can be conductive or sensorineural type. Thyroxine deficiency is responsible for the delay and abnormalities in the auditory brainstem response (ABR), so ABR is used in young children to estimate hearing level and monitor neural conduction.
Aim of the study: The aim of this work is to study the hearing function, frequency and type of hearing impairment among children with congenital hypothyroidism.
Patients and methods: The study was conducted on 41 Children with congenital hypothyroidism aged 3 years and more attending the endocrinology clinic in Alexandria University Childrens Hospital in Egypt. Thorough history and clinical examination were done with emphasis on age of diagnosis and start of treatment, and symptoms of hearing impairment. Thyroid functions were performed. Pure tone audiometer and acoustic impedance were done to evaluate the hearing and middle ear function. Results: It was found that 10 children (24.4%) had hearing impairment; four of them had bilateral conductive hearing impairment and three with sensorineural hearing loss. The mean age of children with hearing impairment was 7.8 years, they started treatment at the mean age of 5 months. Three out of these ten children still had slight high TSH levels. Most of the cases with hearing impairment had mild degrees by pure tone audiometer.
Conclusion: Early screening and treatment of hearing impairment in children with congenital hypothyroidism is important to prevent speech and language development problems.
27 - 29 Sep 2018
European Society for Paediatric Endocrinology