title: Hearing loss in congenital hypothalamic hypothyroidism: a wide therapeutic window.
abstract: In this study, which aims to investigate for the first time auditoty sensitivity in congenital central hypothyroidism (CH), we concluded that: (1) permanent sensorineural hearing loss may be observed not only in congenital primary disorders of thyroid function, as reported hitherto; (2) it may also be found in patients with congenital CH, at least when substitutive treatment is started many years after thyroid failure presentation; (3) the concept of a 'critical therapeutic window' in preventing hearing impairment also holds true for children with congenital CH; (4) the therapeutic window in CH is wider than in primary hypothyroidism; (5) this is probably due to the less severe thyroid impairment in the cases with a central origin of hypothyroidism. These conclusions were suggested by the following data obtained in a cohort of 10 patients with congenital CH who were euthyroid at the time of audiological evaluation thanks to long-standing substitutive therapy: (a) four out of 10 patients exhibited a bilateral sensorineural hearing loss; (b) hearing impaired patients were the oldest of the entire series at diagnosis of hypothyroidism and none of them was aged less than 7 years at the time of the start of replacement therapy; (c) a strong positive relationship was found between age at therapy start and hearing loss.
mesh_terms: D000293:Adolescent; D000328:Adult; D001309:Auditory Threshold; D002648:Child; D002675:Child, Preschool; D003409:Congenital Hypothyroidism; D005260:Female; D006319:Hearing Loss, Sensorineural / Q000209:etiology* / Q000503:physiopathology / Q000517:prevention & control*; D006801:Humans; D007018:Hypopituitarism / Q000150:complications / Q000188:drug therapy / Q000503:physiopathology; D007037:Hypothyroidism / Q000150:complications* / Q000188:drug therapy* / Q000503:physiopathology; D007223:Infant; D008297:Male; D012189:Retrospective Studies; D013963:Thyroid Hormones / Q000172:deficiency / Q000627:therapeutic use*
chemical_list: D013963:Thyroid Hormones