Reflux esophagitis is divided into four grades: ABCD, with grade A being the least severe and grade D being the most severe. Grade D indicates that the esophageal mucosa shows damage and fusion, involving at least 75% of the esophageal circumference. The symptoms of reflux esophagitis mainly include reflux and a burning sensation in the stomach, and some patients may also experience heartburn, nausea, vomiting, and other symptoms. Reflux esophagitis can occur during nighttime sleep in some patients and is caused by the chemical irritation of sensory nerve endings beneath the esophageal epithelium due to acidic or alkaline reflux material.