The utility of middle ear fluid biomarkers in spontaneous cerebrospinal fluid otorrhoea

Background: Cerebrospinal fluid (CSF) otorrhoea presents a challenging clinical scenario necessitating precise biochemical analysis for accurate and timely diagnosis and management. While several studies have investigated the aetiology and management of CSF otorrhoea, few have undertaken a comprehensive biochemical analysis and clarified its clinical implications. We seek to elucidate the significance of biomarkers in this condition in this study. Methods: We performed a retrospective review of medical records and analysis of middle ear fluid samples obtained from patients with spontaneous CSF otorrhoea over a 3-year period in Western Australia. Beta trace protein (BTP) was measured and used to confirm the diagnosis. Additional three biomarkers—bilirubin, glucose, and other proteins—were measured. Statistical analyses were conducted to assess the relationship between biomarker levels and clinical features. Results: Twenty-four patients (13 male, 11 female) were included in this study. The mean BTP concentration was 9.14 mg/L (range, 0.20–25.50 mg/L). The mean bilirubin level was 18.9 µmol/L (range, 10–32 µmol/L), and the mean glucose level was 2.8 mmol/L (range, 1.40–4.30 mmol/L). The mean total protein level was 126.29 g/L (range, 96–147 g/L). We found a statistically significant correlation between glucose levels in middle ear fluid and outcome severity (P=0.03), with a Pearson correlation coefficient of r=0.62, indicating a moderate positive association. Additionally, there was a moderate negative correlation between bilirubin levels and outcome severity (r=−0.32), although the relationship was not statistically significant (P=0.11). Conclusions: The findings underscore the diagnostic potential of biomarkers in spontaneous CSF otorrhoea, their value in predicting severity, and their utility in guiding clinical decisions. Further research is necessary to explore these relationships in greater depth and to confirm the utility of these biomarkers in clinical practice.