RESUMEN
Introduction: Sudden sensorineural hearing loss (SSNHL) is an otological emergency that requires prompt recognition and intervention to prevent devastating impacts on people's lives. During the COVID-19 pandemic, sensory deprivations have been reported in patients positive for SARS-CoV-2 virus, including deleterious effects on the auditory pathway. This study aims to describe the audiological profile of individuals with SSNHL during the COVID-19 pandemic and to correlate hearing recovery in subgroups of individuals with or without COVID-19. Methods: Prospective cohort including patients diagnosed with SSNHL evaluated in a tertiary care center between March 2020 and September 2022. Hearing loss was confirmed with pure-tone and speech audiometry, with Speech Recognition Threshold (SRT) and word recognition score (WRS). Audiometric testing was performed at the moment of diagnosis, then 7, 30 and 120 days after diagnosis. The average degree of hearing loss was assessed by calculating the 4-frequency pure tone average (4fPTA). The investigation of COVID-19 included RT-PCR technique for the SARS-CoV-2 virus and collection of information regarding disease severity. A statistical analysis was performed using an analysis of covariance (ANCOVA) model to compare the 4fPTA between the four groups (with and without a history of COVID-19, unilateral and bilateral cases) at the end of the follow-up period. Results: Fifty-two patients with SSNHL were assessed, 40 (76.9%) with unilateral and 12 (23.1%) with bilateral hearing loss, totaling 64 ears included. Of those, 15 (28.8%) patients tested positive for SARS-CoV-2 and were symptomatic for COVID-19. Of all unilateral cases, 22.5% were seropositive and showed symptoms of COVID-19, a number that increased to 50% for bilateral cases. Comparing the COVID-19 positive groups, individuals with unilateral SSNHL went from 40 dB as their average 4fPTA at onset to 20 dB as their average 4fPTA after 120 days, whereas those with bilateral SSNHL went from an initial average of 60 dB to a final average of 66 dB. Although the 4fPTA value of individuals with unilateral SSNHL improved in 7 days, the mean values showed no significant difference between positive and negative groups. There was a higher incidence of bilateral simultaneous SSNHL in patients who had not been vaccinated against COVID-19 and who presented with symptoms of severe COVID-19. Conclusion: Infection with SARS-CoV-2 resulted in more severe SSNHL, in bilateral SSNHL, and in poorer recovery from SSNHL in bilateral cases. Bilateral SSNHL was seen more frequently in patients who had not received vaccination against COVID-19.
RESUMEN
Introduction: Sudden sensorineural hearing loss (SSNHL) is a common emergency symptom in otolaryngology that requires immediate diagnosis and treatment. SSNHL has a multifactorial etiology, and its pathophysiologic mechanisms may be associated with inflammatory and metabolic changes that may affect the cochlear microenvironment or its nervous component, thus triggering the process or hindering hearing recovery. Therefore, the aim of this study was to assess metabolic and inflammatory changes to identify systemic parameters that could serve as prognostic factors for hearing recovery in patients with SSNHL. Materials and methods: Thirty patients with a sudden hearing loss of at least 30 dB in three contiguous frequencies were enrolled in this study. Patients were followed up for 4 months and peripheral blood samples were collected at 7 days (V1), 30 days (V2) and 120 days (V3). Interleukins (IL)-1F7, IL-2, IL-4, IL-5, IL-6, IL-10, interferon γ (IFN-γ), tumor necrosis factor α (TNF-α) and adiponectin were quantified in serum. In addition, lipid and glycemic profiles as well as concentration of creatinine, uric acid, fructosamine, peroxide, total proteins and albumin were analyzed. Patients underwent weekly ear-specific hearing tests with standard pure tone thresholds for frequencies of 250-8,000 Hz, speech recognition threshold and word recognition score. Results: Patients with SSNHL were divided into a group of patients who did not achieve hearing recovery (n = 14) and another group who achieved complete and significant recovery (n = 16). Most serologic parameters showed no significant changes or values indicating clinical changes. However, IFN-γ levels decreased by 36.3% between V1 and V2. The cytokine TNF-α showed a statistically significant decrease from V1 to V3 (from 22.91 to 10.34 pg./mL). Adiponectin showed a decrease from 553.7 ng/mL in V1 to 454.4 ng/mL in V3. Discussion: Our results show that serologic cytokine levels change in the acute phase of manifestation of SSNHL and establish a parallel between systemic changes and improvements in hearing, especially TNF-α, which showed differences in hearing recovery. The use of IFN-γ, TNF-α and adiponectin may elucidate the clinical improvement in these patients.