Significance of pharyngeal biochemical indexes in the diagnosis of laryngopharyngeal reflux disease

Abstract

Objective: To investigate the significance of the detection of pepsin in saliva and the pharyngeal pH monitoring in the diagnosis of laryngopharyngeal reflux disease(LPRD). Methods: A total of 176 patients (140 patients with simple pharyngitis and 36 patients with space-occupying lesions of larynx) who were suspected to have laryngopharyngeal reflux between February and December 2016 were retrospectively reviewed. All the patients were evaluated with reflux symptom index (RSI), reflux finding score (RFS) and 24-hour pharyngeal pH monitoring(Dx-pH). Saliva of patients was collected and the pepsin in the saliva was measured by enzyme-linked immunosorbent assay (ELISA). Results: The positive rate of RSI (RSI>13) and/or RFS (RFS>7) was 56.8% (100/176). The positive rate of pepsin in saliva was 40.9% (72/176) and pepsin in saliva collected at the time of onset of symptom was much higher than that at other time points (P<0.001). The positive rate of pepsin in saliva, Ryan score and the pH<6.0 laryngopharyngeal reflux in space-occupying lesions group [55.6%(20/36), 27.8% (10/36), 69.4%(25/36), respectively] were all higher than simple pharyngitis group [37.1% (52/140), 5.0% (7/140), 50% (70/140), respectively] (P=0.045, P<0.001, P=0.037, respectively). Conclusions: The detection of pepsin in saliva and the pharyngeal pH monitoring reflected different reflux agents, and there was great significance for the diagnosis of LPRD by using two methods together. We found that the weak acid state and consequent pepsin damage played an important role in the occurrence and development of space-occupying lesions of larynx.