Anatomy, Physiology, and Pathology

Anatomy, Physiology, and Pathology
The esophagus is a flattened, muscular tubular organ running from front to back, and it is the narrowest part of the digestive tract, measuring about 25 cm in length. Morphologically, the most important feature of the esophagus is its three physiological constrictions. The first constriction is at the beginning of the esophagus, corresponding to the lower edge of the sixth cervical vertebra, about 15 cm from the incisors; the second constriction is where the esophagus crosses behind the left main bronchus, roughly between the fourth and fifth thoracic vertebrae, about 25 cm from the incisors; the third constriction is where the esophagus passes through the esophageal hiatus in the diaphragm, around the tenth thoracic vertebra, about 40 cm from the incisors. These three constrictions are common sites for foreign bodies to get stuck and for esophageal cancer to develop.
Esophagitis (RE) refers to inflammation of the esophageal mucosa and functional impairment caused by gastroesophageal reflux, in which gastric contents flow back into the esophagus, irritating the mucosa with gastric acid, pepsin, bile salts, pancreatic enzymes, and other substances. Currently, this condition is classified as gastroesophageal reflux disease. Gastroesophageal reflux disease (GERD) refers to symptoms such as heartburn and reflux caused by gastroesophageal reflux, including reflux esophagitis (RE) and non-erosive reflux disease (NERD), the latter also known as endoscopically negative reflux disease.
The lesions of reflux esophagitis mainly occur in the lower esophagus, sometimes extending to the middle esophagus. Macroscopically, the inflamed mucosa appears diffusely or patchily congested and edematous; in severe cases, erosion or ulcers may be visible, and occasionally the mucosa takes on a fine granular texture, sometimes with fibrotic patches. If the esophageal mucosa repeatedly forms ulcers, it may eventually lead to scarred stenosis. Histopathologically, the basal cell layer of the squamous epithelium proliferates, and the papillae extend toward the epithelial surface. Because the papillae contain blood vessels and acid-sensitive nerve endings, when the papillae approach the mucosal surface, the refluxed gastric acid stimulates these nerve endings, causing the patient to experience heartburn.
II. Diagnosis and Treatment
( --- ) Clinical Diagnosis 1. Clinical Symptoms
( 1 ) Burning discomfort or pain behind the sternum, which can be triggered or aggravated by lying down or bending over, and relieved by standing upright or taking antacids.
( 2 ) In the early stages, intermittent dysphagia or pain behind the sternum during swallowing may occur; in later stages, persistent dysphagia may develop.
( 3 ) Some patients may develop chronic pharyngitis, laryngitis, or aspiration bronchitis and pneumonia due to irritation from refluxed materials.
2. Laboratory Tests
( 1 ) Esophageal Acid Infusion Test
0.1 equivalent of hydrochloric acid is infused through a nasogastric tube at a rate of 10–12 ml per minute. If heartburn or burning sensation occurs within 15 minutes, it suggests the presence of esophagitis.
( 2 ) Lower Esophageal pH Measurement
A specially designed microelectrode is inserted 5 cm above the lower esophageal sphincter, and the pH of the lower esophagus is measured in different body positions. If the pH is less than 4, it indicates gastroesophageal reflux. Recently, continuous 24-hour monitoring of esophageal pH has become increasingly popular, which is highly valuable for diagnosis, but loses diagnostic value for those with excessively low gastric acid secretion or alkaline reflux.
( 3 ) Esophageal Intraluminal Pressure Measurement
Normal intraluminal pressure of the esophagus is 1.6–2.7 kPa. If the pressure is ≤1.3 kPa, or if the intraluminal pressure relative to the gastric pressure drops to ≤1 after abdominal compression or leg elevation (normal is >1), it suggests gastroesophageal reflux.
( 4 ) Radioisotope Scan of the Stomach and Esophagus
Can reveal gastroesophageal reflux and estimate its severity.
( 5 ) Esophagoscopy and Biopsy
Esophagoscopy can show mucosal congestion, edema, erosion, superficial ulcers, and other findings, which are of great diagnostic value. Pathological biopsy can reveal basal cell proliferation, papillary extension to the epithelium, vascular hyperplasia, and nonspecific inflammatory changes.
( 6 ) Barium Swallow X-ray
Can show weakened esophageal peristalsis, uncoordinated movement, or spasms; in severe cases, the mucosal folds become disordered, and increased abdominal pressure can exacerbate reflux.
3. Differential Diagnosis
( 1 ) Achalasia of the Esophageal Cardia
Both achalasia of the esophageal cardia and reflux esophagitis can present with pain behind the sternum, dysphagia, and food reflux; however, in achalasia, the refluxed material does not come into contact with gastric acid and therefore is not acidic. On X-ray, the upper esophagus is dilated, while the lower esophageal lumen tapers gradually into a cone-shaped, bird-beak-like or funnel-like form with smooth edges; the intraluminal static pressure does not decrease but tends to increase. In contrast, reflux esophagitis does not exhibit these features on X-ray, instead showing disordered mucosal folds and a decrease in intraluminal static pressure.
( 2 ) Esophageal Cancer
Both conditions can present with discomfort, pain, difficulty swallowing, or dysphagia behind the sternum. The most important method of differentiation is endoscopic examination, directly observing mucosal changes and performing pathological biopsy for confirmation.
( 3 ) Coronary Heart Disease
Patients with reflux esophagitis primarily presenting with pain behind the sternum need to be differentiated from coronary heart disease, which is often accompanied by palpitations and shortness of breath, and may show positive findings on electrocardiogram.
( 4 ) Drug-Induced Esophagitis
Frequent use of certain medications, such as aspirin and nonsteroidal anti-inflammatory drugs, can cause drug-induced esophagitis if taken before bedtime or without drinking enough water. Patients may also experience heartburn, pain during swallowing, and difficulty swallowing, but drug-induced esophagitis patients usually have a history of frequent medication use, with lesions often located in the middle esophagus at the level of the aortic arch, frequently presenting as solitary ulcers, and sometimes as clusters of oval-shaped ulcers.
( II ) Western Medical Treatment

1. Pharmacological Treatment
   ( 1 ) Acid-Suppressing Therapy
   Potent proton pump inhibitors (PPIs) can produce significant and lasting acid-suppressing effects, quickly relieving symptoms and achieving high healing rates for RE. Commonly used drugs and dosages are similar to those for peptic ulcers; it should be emphasized that the dosage must be sufficient, often twice the therapeutic dose for peptic ulcers, with a treatment course of at least 8–12 weeks. Conventional H2 receptor antagonists effectively suppress gastric acid secretion on an empty stomach and at night, alleviating symptoms for some RE patients, but their healing rate for severe RE is poor, so they are only used for mild to moderate RE cases.
   ( 2 ) Prokinetic Agents
   These drugs do have some effect, but their efficacy is poor when used alone.
   ( 3 ) Other
   Antacids can neutralize gastric acid; commonly used preparations include alkaline salts containing aluminum, magnesium, bismuth, and their compound formulations, which can relieve symptoms but have almost no effect on healing RE.
   ( 4 ) Maintenance Therapy
   PPIs can almost cure all cases of RE, but the relapse rate reaches 80% six months after stopping medication, so maintenance therapy is essential. The effectiveness of PPI maintenance therapy is superior to that of H2 receptor antagonists and prokinetic agents, and there is no unified standard for the dosage of maintenance medications; generally, the usual dose of PPI is used.

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2. Surgical Treatment
   Surgical treatment is required for critically ill patients whose internal medical treatment has failed or who have esophageal scar stenosis.

3. Professor Pei Zhengxue's Thinking Method
   Traditional Chinese Medicine classifies this disease under categories such as "noisy," "acid regurgitation," "chest oppression," and "vomiting." The primary affected organ is the stomach, which is closely related to the five zang organs. The stomach resides in the middle jiao, belongs to the earth element, and governs the smooth flow and downward movement of qi. It has a superficial-internal relationship with the spleen and a mother-child relationship with the heart and lungs. Zhang Jingyue once proposed, "Those who are good at treating the spleen and stomach can also regulate the five zang organs, and conversely, regulating the five zang organs can also treat the spleen and stomach." This demonstrates that the stomach and the five zang organs are not only closely related physiologically but also influence each other pathologically. Professor Pei Zhengxue believes that this disease is mostly characterized by excess patterns, which often manifest as liver qi stagnation, upward rebellion of stomach qi, phlegm-heat accumulation, and food stagnation. Therefore, when making a diagnosis, it is essential to distinguish between deficiency and excess, cold and heat. Treatment should focus on soothing the liver and regulating qi, harmonizing the stomach and descending rebellious qi, clearing heat and transforming phlegm, and eliminating food stagnation and promoting bowel movements. The commonly used basic formula is Si Ni San, which is a classic prescription for soothing the liver and resolving depression, as well as harmonizing the liver and spleen. In this formula, Chai Hu soothes the liver and resolves depression, lifting clear yang to dispel stagnant heat, serving as the chief herb; Bai Shao nourishes the blood and collects yin, working in conjunction with Chai Hu to allow stagnant heat to dissipate without harming yin, serving as the assistant herb; Zhuo Shi promotes qi circulation and disperses stagnation, enhancing the effect of smoothing qi flow; and Zhi Gan Cao moderates urgency and harmonizes the center while also balancing the other herbs as the guiding herb. On this basis, according to different syndrome differentiation types, formulas such as Xuan Fu Dai Zhe Tang, Dan Zhi Xiao Yao San, Huang Lian Wen Dan Tang, Ban Xia Hou Pu Tang, Yue Ju Wan, Xiang Sha Liu Jun Zi Tang, Si Jun Zi Tang, and Pei's Stomach-Nourishing Decoction are added or subtracted as needed.

4. TCM Syndrome Differentiation and Formulas

5. Liver-Stomach Disharmony Syndrome
   Symptoms: Due to emotional distress, there is fullness and distension in the epigastric region, accompanied by pain that radiates to both flanks and the chest, along with chest tightness and blockage, frequent belching, acid regurgitation and hiccups, loss of appetite, unsatisfactory bowel movements, a thin white tongue coating, and a wiry pulse. Treatment principle: Soothe the liver and regulate qi, harmonize the stomach and descend rebellious qi.
   Formula: Si Ni San combined with Xuan Fu Dai Zhe Tang, with modifications: Chai Hu 10g, Zhuo Shi 10g, Bai Shao 15g, Ban Xia 10g, Chen Pi 6g, Fu Ling 15g, Sheng Jiang 6g, Dai Zhe Shi 15g, Zi Su Geng 15g, Yu Jin 10g, and Zhi Gan Cao 6g. In this formula, Chai Hu soothes the liver and resolves depression, while also promoting qi circulation and relieving stagnation; Bai Shao nourishes the liver and collects yin; Ban Xia, Sheng Jiang, and Dai Zhe Shi transform phlegm and disperse stagnation, harmonizing the stomach and descending rebellious qi; Zi Su Geng and Chen Pi broaden the middle burner and regulate qi, further harmonizing the stomach and descending rebellious qi, collectively achieving the effects of soothing the liver and regulating qi, as well as harmonizing the stomach and descending rebellious qi.

6. Liver-Stomach Heat Accumulation Syndrome
   Symptoms: Burning sensation or burning-like pain behind the sternum or below the xiphoid process, fullness in the stomach, worsening pain behind the sternum after eating, acid regurgitation and belching, hiccups, irritability and quick temper, bitter taste and dry throat, dry stools, a yellow and greasy tongue coating, and a wiry, rapid pulse. Treatment principle: Soothe the liver and release heat, clear the gallbladder and harmonize the stomach.
   Formula: Dan Zhi Xiao Yao San combined with Huang Lian Wen Dan Tang, with modifications: Chai Hu 10g, Dan Pi 10g, Zhi Zi 10g, Huang Lian 6g, Zhi Shi 10g, Bai Shao 15g, Ban Xia 10g, Chen Pi 6g, Fu Ling 10g, Sheng Jiang 6g, Zhu Ru 10g, Zi Su Geng 10g, and Gan Cao 6g. In this formula, Chai Hu soothes the liver and resolves depression, Zhuo Shi promotes qi circulation and relieves stagnation, Bai Shao nourishes the liver and collects yin, Ban Xia, Sheng Jiang, and Dai Zhe Shi transform phlegm and disperse stagnation, harmonizing the stomach and descending rebellious qi; Dan Pi, Shan Zhi Zi, Huang Lian, and Zhu Ru clear and release heat from the liver and gallbladder; Zi Su Geng, Chen Pi, and others broaden the middle burner and regulate qi, further harmonizing the stomach and descending rebellious qi, collectively achieving the effects of soothing the liver and releasing heat, as well as harmonizing the stomach and descending rebellious qi.

7. Phlegm-Qi Obstruction Syndrome
   Symptoms: A feeling of obstruction and discomfort in the throat, fullness and oppression in the chest and diaphragm, sometimes even pain, belching and hiccups, vomiting phlegm or regurgitating food immediately after eating, dry mouth and throat, difficult bowel movements, a thin or greasy tongue coating, and a wiry, slippery pulse. Treatment principle: Regulate qi and transform phlegm, broaden the chest and clear the diaphragm.
   Formula: Ban Xia Hou Pu Tang combined with Yue Ju Wan, with modifications: Ban Xia 10g, Hou Pu 10g, Zi Su Geng 10g, Sheng Jiang 6g, Fu Ling 10g, Chuan Xiong 6g, Xiang Fu 10g, Shan Zhi Zi 10g, Cang Zhu 10g, Shen Qu 10g, Dan Shen 10g, Sha Ren 6g, Yu Jin 10g, Guai Wei 15g, and Sheng Gan Cao 6g. In this formula, Ban Xia and Sheng Jiang transform phlegm and disperse stagnation, harmonizing the stomach and descending rebellious qi; Hou Pu, Zi Su Geng, and Guai Wei promote qi circulation and disperse stagnation, broadening the chest and clearing the diaphragm; Dan Shen, Chuan Xiong, and Yu Jin activate qi and invigorate blood, dissolving stasis and relieving pain; Cang Zhu, Sha Ren, and Shen Qu dry dampness and strengthen the spleen, eliminating food stagnation and promoting bowel movements.

8. Spleen-Stomach Deficiency Syndrome
   Symptoms: Dull, persistent pain in the epigastric region, a constant feeling of water in the mouth, a sensation of blockage in the chest and diaphragm when eating, lack of appetite, fatigue and weakness, thin stools, a thin white tongue coating, and a weak, fine pulse. Treatment principle: Tonify qi and strengthen the spleen, harmonize the stomach and descend rebellious qi.