To understand better the pathogenesis of inner ear (IE) damage caused by otitis media (OM), the round window membrane(RWM) structure was investigated in a rat model for pneumococcal otitis media (POM). The RWM of 25 rats were evaluated light and electron microscopically on 1 day, 3 days, 6 days, 10 days, and 20 days after the unilateral inoculation of type 3 pneumococcus suspension into their middle ear cavities. The thickness of the RWM increased in various stages of the pneumococcus-evoked otitis media, compared with that of the normal. The thickening was most pronounced on day 1, being about 4 to 5 times greater than that of the normal RWM. All layers of the RWM were affected by the pneumococcal infection, but the major changes were confined to the subepithelial space close to the basement membrane (BM). Together with alterations to the BM, the most distinct pathological features were characterized by an increase and hypertrophy of fibroblasts in association with abundant collagen fibers. Elastic fibers observed close to the inner mesothelial layer under a high power magnification also increased during the experiment. These results will be relevant to a better understanding of the histologic implication of RWM in stages of acute otitis media involving pneumococcus-evoked otitis media.
Animals ; Disease Models, Animal ; Disease Progression ; Ear, Middle/pathology/*ultrastructure ; Male ; Otitis Media/*pathology ; Pneumococcal Infections/*pathology ; Rats ; Rats, Sprague-Dawley ; Streptococcus pneumoniae ; Time Factors

BACKGROUNDThe prevalence of sudden sensorineural hearing loss in children (CSSNHL) is consistently increasing. However, the pathology and prognosis of CSSNHL are still poorly understood. This retrospective study evaluated clinical characteristics and possible associated factors of CSSNHL.

METHODSOne hundred and thirty-six CSSNHL patients treated in Department of Otolaryngology-Head and Neck Surgery and Institute of Otolaryngology at Chinese PLA General Hospital between July 2008 and August 2015 were included in this study. These patients were analyzed for clinical characteristics, audiological characteristics, laboratory examinations, and prognostic factors.

RESULTSAmong the 136 patients (151 ears), 121 patients (121 ears, 80.1%) were diagnosed with unilaterally CSSNHL, and 15 patients (30 ears, 19.9%) with bilateral CSSNHL. The complete recovery rate of CSSNHL was 9.3%, and the overall recovery rate was 37.7%. We found that initial degree of hearing loss, onset of treatment, tinnitus, the ascending type audiogram, gender, side of hearing loss, the recorded auditory brainstem response (ABR), and distortion product otoacoustic emissions (DPOAEs) had prognostic significance. Age, ear fullness, and vertigo had no significant correlation with recovery. Furthermore, the relevant blood tests showed 30.8% of the children had abnormal white blood cell (WBC) counts, 22.1% had elevated homocysteine levels, 65.8% had high alkaline phosphatase (ALP), 33.8% had high IgE antibody levels, and 86.1% had positive cytomegalovirus (CMV) IgG antibodies.

CONCLUSIONSCSSNHL commonly occurs unilaterally and results in severe hearing loss. Initial severe hearing loss and bilateral hearing loss are negative prognostic factors for hearing recovery, while positive prognostic factors include tinnitus, gender, the ascending type audiogram, early treatment, identifiable ABR waves, and DPOAEs. Age, vertigo, and ear fullness are not correlated with the recovery. Some serologic indicators, including the level of WBC, platelet, homocysteine, ALP, positive CMV IgG antibody, fibrinogen, and some immunologic indicators, are closely related to CSSNHL.

Adolescent ; Child ; Child, Preschool ; Evoked Potentials, Auditory, Brain Stem ; Female ; Hearing Loss, Sensorineural ; blood ; etiology ; physiopathology ; Humans ; Male ; Otoacoustic Emissions, Spontaneous ; Retrospective Studies