1. What is pharyngeal reflux? Pharyngeal reflux is defined as a chronic symptom or mucosal damage caused by abnormal regurgitation of gastric contents into the upper respiratory tract. In addition to pepsin and gastric acid, stomach contents include bile acids as well as pancreatic enzymes, which can damage tissues that cannot tolerate these substances. Pharyngeal reflux can cause posterior laryngeal inflammation, contact laryngeal ulcers, subglottic stenosis, laryngospasm, vocal difficulties, pharyngitis, asthma, pneumonia, nocturnal dyspnea, and many other symptoms. Recently, laryngeal reflux is also suspected to be a major factor causing laryngeal cancer in patients without a history of tobacco or alcohol exposure, although the exact relationship between reflux and cancer is still unclear. 2. What are the pathogenesis and pathophysiological features? Gastroesophageal reflux disease (GERD) is defined as a chronic symptom or mucosal damage caused by abnormal regurgitation of gastric contents into the esophagus. Typical GERD symptoms include heartburn, regurgitation, dysphagia, cough and atypical chest pain. The occurrence of pharyngeal reflux and GERD are inextricably linked. GERD is a lesion of the lower esophageal sphincter and occurs mainly at night in the supine position. In contrast, pharyngeal reflux is mainly seen in the upper sphincter of the gastroesophagus and often occurs in the upright position during the day, especially during strong physical activity, and is less likely to be associated with esophageal dysmotility. Patients with pharyngeal reflux often present with complaints of throat symptoms without heartburn or regurgitation. The larynx is more susceptible to chemical erosion by gastric acid or pepsin than the esophagus because of its thinner epithelium and lack of the multiple layers of esophageal barriers to gastric acid (e.g., lower esophageal sphincter, active acid contouring motility of the esophagus, acid resistance of esophageal mucosal tissue, and upper gastroesophageal sphincter). For the esophagus, 50 refluxes per day are normal, while for the pharynx, 4 refluxes per day are considered abnormal. Experiments have shown that exposure of the larynx to acid 3 times a week can cause pathological damage. 3. What are the clinical manifestations of pharyngeal reflux? The clinical symptoms of pharyngeal reflux are complex and varied, including intermittent vocal difficulties, chronic throat clearing, excessive laryngeal mucus, cough, postnasal drip sensation (PND), dysphagia, taste disturbance, halitosis and pharyngeal bulb sensation. Signs seen endoscopically that are most closely related to pharyngeal reflux include: erythema of the arytenoid cartilage, erythema and edema of the vocal cords, posterior commissure hypertrophy, and arytenoid edema. In addition, cobblestone changes in the posterior larynx, arytenoid interchondral bulge, congestion, granuloma, contact ulcers, subglottic stenosis, postglottic stenosis, and vocal fold lesions are also of diagnostic value for pharyngeal reflux. 4. How to diagnose pharyngeal reflux? Due to the diversity and non-specificity of pharyngeal reflux symptoms and signs, it is now internationally believed that a more accurate diagnosis of pharyngeal reflux can be made by combining several aspects of symptoms, laryngoscopy, p H monitoring and empirical nature of mercury inhibitor (PPI) treatment. 5.How to treat pharyngeal reflux? Pharyngeal reflux is a disease that involves multiple manifestations in otorhinolaryngology, respiratory medicine and gastroenterology, so the treatment of pharyngeal reflux is controversial and effective treatment options have not yet been standardized. At this stage, the recommended treatment plan includes the following: for milder cases of reflux, conservative treatment is first used, including a soft diet and lifestyle changes, i.e., weight loss, cessation of smoking and alcohol, limiting the intake of fatty foods, citrus fruits, carbonated beverages, red wine, and caffeine, and avoiding intra-abdominal pressure-increasing movements such as wearing tight clothing and bending over. Fasting and abstaining from food and drink 3h before bedtime, and elevating the head of the bed to avoid reflux of gastric contents can be effective for patients with mild reflux. Antacids and H2 receptor antagonists are added for patients for whom conservative treatment is ineffective. Sodium alginate can form a barrier at the top of the stomach to stop the reflux of gastric contents into the esophagus, which can significantly reduce the number of refluxes, the height of refluxes and the percentage time of esophageal acid p H < 4,0. For more severe reflux, a combination of conservative treatment plus proton mercury inhibitors is recommended. Patients with proven high volume fluid reflux with lower esophageal sphincter insufficiency who have failed pharmacologic therapy are best treated surgically. Common procedures include laparoscopic complete fundoplication and partial fundoplication.