RESUMEN
OBJECTIVE: The purpose of this study was to evaluate the efficacy of intratympanic administration of dexamethasone (IT-DEX) treatment on sudden sensorineural hearing loss (SSNHL) patients with diabetes by comparing the results with intravenous administration of dexamethasone (IV-DEX) treatment. STUDY DESIGN: Comparative study. SETTING: University hospital and affiliated hospital. PATIENTS: Ten sequential SSNHL patients with diabetes receiving IT-DEX and 21 sequential SSNHL patients with diabetes receiving IV-DEX. Patients with low tone hearing loss were excluded. INTERVENTION: In the IT-DEX group, two methods were applied to deliver DEX (4 mg/ml): injection through a perforation made by laser-assisted myringotomy or through a tympanostomy tube. IT-DEX administration was performed on 8 sequential days. In the IV-DEX group, DEX was administrated intravenously starting from an amount of 8 mg/d followed by taped doses for 10 days. MAIN OUTCOME MEASURES: Preprocedure and postprocedure hearing levels and complications. RESULTS: In the IT-DEX group, the average hearing level before the treatment was 79 dB. Overall, all 10 patients showed improvement of more than 10 dB in the pure-tone audiogram, with a mean improvement of 41 dB. Seven patients (70%) demonstrated successful results, and four recovered completely. In the IV-DEX group, 14 (67%) of the 21 patients showed improvement of more than 10 dB with a mean improvement of 25 dB. Thirteen patients (62%) demonstrated successful results. Free blood sugar during and after the IT-DEX treatment remained below the pretreatment levels, whereas four patients in the IV-DEX group demonstrated worsening of the hyperglycemia. CONCLUSION: IT-DEX treatment is at least as effective as IV-DEX treatment for SSNHL patients with diabetes.
Asunto(s)
Dexametasona/administración & dosificación , Complicaciones de la Diabetes/tratamiento farmacológico , Glucocorticoides/administración & dosificación , Pérdida Auditiva Sensorineural/tratamiento farmacológico , Pérdida Auditiva Súbita/tratamiento farmacológico , Membrana Timpánica/cirugía , Adulto , Anciano , Anciano de 80 o más Años , Dexametasona/uso terapéutico , Femenino , Glucocorticoides/uso terapéutico , Humanos , Inyecciones Intravenosas , Terapia por Láser , Masculino , Persona de Mediana Edad , Ventilación del Oído Medio , Resultado del TratamientoRESUMEN
Gamma-aminobutyric acid (GABA) is thought to be the major inhibitory neurotransmitter in the central nervous system. Although it is distributed in the olivo-cochlear bundles, which constitute the mammalian cochlear efferent system, its function in the cochlea is still obscure. In this study, we investigated the localization of GABAa receptor subunits (alpha1-6, beta1-3, gamma) in the rat cochlea in order to determine the role of GABA in the cochlea. Most spiral ganglion cells were intensely immunolabeled with all the anti-GABAa receptor subunit antibodies. In the organ of Corti, punctate immunoreactivities were observed in inner hair cell regions corresponding to the distribution of GABA. These data suggest that GABAa receptor was present in afferent nerve terminals in inner hair cell regions, and that GABA regulated afferent nerve transmission contacting efferent nerve endings by means of the axo-dendritic synapse function.