Biomarkers Suggesting Favorable Prognostic Outcomes in Sudden Sensorineural Hearing Loss.

Jeon Gang Doo,Dokyoung Kim,Seung Geun Yeo,Yong Kim,Jeewon Ryu,Myung Chul Yoo,Sung Su Kim

doi:10.3390/ijms21197248

Abstract

Sudden sensorineural hearing loss (SSNHL) is a medical emergency, making detailed examination to determine possible causes and early treatment important. However, etiological examinations in SSNHL do not always reveal a cause, and several factors have been found to affect treatment outcomes. Various studies are being performed to determine the prognosis and effects of treatment in patients who experience sudden hearing loss, and to identify biomarkers associated with this condition. Embase, PubMed, and the Cochrane database were searched using the key words SSNHL, prognostic, and biomarker. This search identified 4 articles in Embase, 28 articles in PubMed, and 36 in the Cochrane database. Of these 68 articles, 3 were duplicates and 37 were unrelated to the research topic. After excluding these articles, the remaining 28 articles were reviewed. Factors associated with SSNHL were divided into six categories: metabolic, hemostatic, inflammatory, immunologic, oxidative, and other factors. The associations between these factors with the occurrence of SSNHL and with patient prognosis were analyzed. Low monocyte counts, low neutrophil/lymphocyte ratio (NLR) and monocyte/high-density lipoproteins (HDL) cholesterol ratio (MHR), and low concentrations of fibrinogen, platelet glycoprotein (GP) IIIa, and TNF-α were found to be associated with good prognosis. However, these factors alone could not completely determine the onset of and recovery from SSNHL, suggesting the need for future basic and clinical studies.

Highlights

Sudden sensorineural hearing loss (SSNHL) is defined as sensorineural hearing loss of more than 30 dB at more than three consecutive wavelengths occurring within 3 days
Neutrophil count in patients with SSNHL was found to correlate positively with hearing level at the initial visit (r = 0.64, p = 0.00001) and negatively with recovery rate after one week (r = −0.63, p = 0.00003) and final recovery rate (r = −0.63, p = 0.00002). These findings suggested that neutrophil counts exceeding the reference range could be a clinical indicator of SSNHL severity and prognosis and may be related to the pathogenesis of idiopathic sudden hearing loss (ISHL) [24]
tumor necrosis factor-α (TNF-α) levels in non-responders to treatment were higher after than before treatment. These findings suggested that IL-10 and IL-12 do not play important roles in SSNHL, whereas TNF-α is associated with the pathophysiology of ISSHL, suggesting that TNF-α receptor blockers may be effective in these patients [45]

Summary

Introduction

Sudden sensorineural hearing loss (SSNHL) is defined as sensorineural hearing loss of more than 30 dB at more than three consecutive wavelengths occurring within 3 days. Its annual reported prevalence rates are 5–20 per 100,000 in the United States and >10 per 100,000 in Korea [1]. SSNHL can occur at any age, but it is most prevalent in individuals aged in their 30 s to 50 s. SSNHL is idiopathic and occurs unilaterally, but 4–17% of patients have bilateral SSNHL [2,3]. This condition is likely multifactorial, as responses to treatment and prognosis vary. Detection and treatment greatly affect prognosis, making rapid diagnosis important [1,4,5]

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