Cardia dystrophy: also known as cardia spasm and megaesophagus, is a disease caused by neuromuscular dysfunction of the esophagus, which is mainly characterized by a lack of peristalsis in the esophagus, high pressure in the lower esophageal sphincter (LES), and a weakened flaccid response to swallowing movements. Clinical manifestations include dysphagia, food regurgitation and lower retrosternal discomfort or pain. It is a rare disease (estimated to be only about 1 per 100,000 people) that can occur at any age, but is most common in the 20- to 39-year-old age group. It is rare in children, occurs in both sexes about equally, and is more common in Europe and North America. Pathogenesis The etiology of the disease is unknown to date. It is generally recognized as a neurogenic disease. Lesions are seen in the esophageal wall with a decrease or even complete absence of ganglion cells in the vagus nerve and its dorsal nucleus and in the intermuscular plexus of the esophageal wall, but the decrease in the LES is less severe than in the esophageal body leading to it. The LES reflexively relaxes at the onset of a normal swallowing maneuver, and its pressure decreases to facilitate the entry of food into the gastric lumen. When there is vagal dysfunction or damage to the intramuscular plexus of the esophageal wall, the LES pressure can rise to about 6.67 kPa (50 mmHg). After the swallowing action, the pressure does not fall, and the LES cannot relax, so that the food cannot enter the stomach smoothly; coupled with the propulsive peristalsis of the esophagus can not, can not push the food forward. As a result, a large amount of food and water is stagnated in the esophagus until it weighs more than the LES pressure, and then it has to enter the stomach. Due to the retention of food, the esophagus is initially dilated in the form of a shuttle, and then gradually elongated and curved. The degree of esophageal dilatation is much more prominent than that caused by esophageal cancer or other esophageal diseases, and its volume can be up to 1L or more. In addition, the wall of the esophagus may have discrete hypertrophy, inflammation, diverticulum, ulceration or carcinoma, resulting in corresponding clinical symptoms. Clinical manifestations 1. Dysphagia: Painless dysphagia is the most common and earliest symptom of the disease, accounting for 80%～95% of the cases. The onset of the disease is usually slow, but it can also be more urgent, and it can be mild at the beginning, and only have a feeling of fullness after meals. Dysphagia is often intermittent, often triggered by mood swings, anger, anxiety, shock or eating irritating foods such as cold and spicy food. At the beginning of the disease, dysphagia is sporadic, sometimes mild, sometimes severe, and then becomes persistent at a later stage. In a few patients, swallowing liquids is more difficult than solid food, and this sign has been used to distinguish dysphagia from other organic esophageal strictures. However, most patients have more difficulty swallowing solids than liquids, or swallowing both solid and liquid food with equal difficulty. Pain: about 40% to 90%, the nature of the pain varies, can be boring pain, burning pain, pins and needles, cutting pain or cone pain. The pain site is mostly in the back of the sternum and the middle-upper abdomen; it can also be in the back of the chest, the right side of the chest, the right sternal border and the left quarter of the ribs. The pain episodes sometimes resemble angina pectoris and may even be relieved by sublingual nitroglycerin tablets. The mechanism of pain can be due to strong contraction of esophageal smooth muscle, or food retention esophagitis. With the gradual aggravation of dysphagia and the further dilatation of the esophagus above the obstruction, the pain can be gradually reduced. 3, food reflux: the incidence of up to 90%, with the aggravation of dysphagia, esophageal further expansion, a considerable amount of content can be retained in the esophagus to several hours or days, and reflux out of the change in body position. The refluxed contents from the esophagus do not have the characteristics of gastric vomitus because they have not entered the gastric cavity, but they may be mixed with large amounts of mucus and saliva. When complicated by esophagitis and esophageal ulcer, the refluxed material may contain blood. Weight loss: Weight loss is associated with dysphagia affecting food intake. For dysphagia, although the patients mostly adopt the methods of choosing food, eating slowly, rushing down the food with more soup during or after eating, or stretching out the chest and back, taking deep breaths or exchanging breaths after eating in order to assist the swallowing action, so as to make the food enter into the stomach and ensure the nutritional intake. The long duration of the disease can still have weight loss, malnutrition and vitamin deficiency and other manifestations, while the malignant disease is rare. Bleeding and anemia: Patients may have anemia and occasionally bleeding caused by esophagitis. 6, other symptoms: due to the increased tension of the lower esophageal sphincter, the patient seldom occurs eructation, which is an important feature of this disease. In late cases, the extremely dilated esophagus may compress the organs in the chest cavity and produce dry cough, shortness of breath, cyanosis and hoarseness. X-ray examination is most important for the diagnosis and differential diagnosis of this disease. Barium meal: Barium meal is often difficult to pass through the cardia and is trapped in the lower esophagus, showing a 1-3 cm long, symmetrical, funnel-shaped stenosis with mucosal lines, and the upper esophagus shows different degrees of dilatation, length, and curvature, with no peristaltic wave. The esophageal cardia may be relaxed by hot drinks, sublingual nitroglycerin tablets, or inhalation of isoamyl nitrite; and the cardia may be more difficult to relax by cold drinks. Retained food residue can show filling defect in barium meal contrast, so esophageal drainage and irrigation should be done before examination. Chest radiograph: In the early stage of the disease, there is no abnormality in the chest radiograph. With the expansion of the esophagus, the right upper edge of the mediastinum can be seen in the posterior-anterior chest radiograph. When the esophagus is highly dilated, extended and curved, the mediastinum can be seen to widen and exceed the right edge of the heart, which can sometimes be misdiagnosed as mediastinal tumor. When a large amount of food and gas is trapped in the esophagus, a fluid level is seen in the esophagus. Loss of gastric vesicles is seen in most cases. (II) Acetylmethacholine (mecholyl) test In normal people, after subcutaneous injection of acetylmethacholine 5-10mg, esophageal peristalsis increases pressure without significant increase. However, in patients with this disease, a strong contraction of the esophagus can be produced from 1 to 2 minutes after injection; the pressure in the esophagus increases abruptly, resulting in severe pain and vomiting, and the X-ray sign is more obvious (atropine should be prepared for this test in case of a violent reaction). Extreme dilatation of the esophagus does not respond to this drug, so that the test result is negative; gastric cancer involving the interbrachial plexus of the esophagus as well as some diffuse esophageal spasms, this test can also be positive. It can be seen that the test lacks specificity. （Endoscopy and cytology are of little help in the diagnosis of this disease, but can be used in the differential diagnosis between this disease and esophageal cardia cancer. Diagnosis Difficulty in swallowing, food reflux and retrosternal pain are the typical clinical manifestations of this disease. If the typical signs of this disease are found on barium swallow X-ray examination of the esophagus, the diagnosis can be made. Differential diagnosis 1, pseudolossophrenia patients have symptoms of dysphagia, X-ray examination of the body of the esophagus has dilated, the distal sphincter can not be relaxed, manometry and X-ray examination are no peristaltic wave. This condition occurs in diseases in which there are infiltrative lesions present in the submucosal layer of the esophageal junction and the intestinal muscular plexus. The most common cause is infiltration by gastric cancer, and similar signs can be found in other rare diseases such as lymphoma and amyloidosis, and hepatocellular carcinoma. The segment cannot be passed through instruments without pre-dilatation during endoscopy because of the rigidity of the infiltrating lesion. In most cases, biopsy can confirm the diagnosis, and sometimes it is necessary to explore to confirm the diagnosis. 2. Non-peristaltic anomalous scleroderma can result in a non-peristaltic segment of the distal esophagus and cause diagnostic difficulties. Esophageal involvement often precedes cutaneous manifestations. Esophageal manometry reveals that the proximal esophagus is often uninvolved, while the peristaltic wave in the body of the esophagus is minimal, and the distal sphincter is often weak, but with normal relaxation. Peristaltic dysfunction can also be seen in associated peripheral neuropathies such as diabetes mellitus and multiple sclerosis. 3.Dysphagia after vagotomy can occur after vagotomy via thoracic or abdominal route. Transient dysphagia can occur in about 75% of patients after highly selective vagotomy. In most cases, the symptoms gradually resolve by 6 weeks postoperatively, and failure of the distal esophageal sphincter to relax and occasional peristalsis may be seen on x-ray and manometry, but dilation and surgical treatment are rarely required. It can be differentiated on the basis of medical history. 4. Esophageal motility disorders in the elderly are due to degenerative changes in the organs that manifest in the esophagus. Most older adults are found to have poor esophageal motility on manometry, with primary and secondary peristalsis, and frequent non-peristaltic contractions after swallowing or spontaneously. Lower esophageal sphincter relaxation is reduced or absent, but intraesophageal resting pressure does not increase. 5. Chagas’ disease can have megaesophagus, a locally prevalent South American trypanosome-parasitic disease with concomitant involvement of systemic organs. Its clinical manifestations are not easily differentiated from achalasia. Because of the degeneration of the intestinal muscular plexus secondary to parasitic infection, the physiology, pharmacology, and response to treatment are similar to those of primary achalasia.In addition to esophageal lesions, Chagas’ disease is associated with other visceral changes. Before diagnosis, it must be determined that the patient has lived in South America or South Africa, and a past history of trypanosomiasis infection can be determined by fluorescent immunization and complement binding tests. 6.Cancer of esophagus and cardia: cardia achalasia is a disease in which the LES cannot be relaxed, only the lower end of esophagus is tightly closed and not open, there is no obvious abnormality of cardia-esophageal mucosa, and the lower end of esophagus and cardia wall are well dilated passively, so that the endoscopic lens can be passed through the gastric lumen smoothly except for the slight resistance. Stenosis caused by esophageal cardia cancer is due to the infiltration of cancerous tissues into the wall of the tube, the mucosa is damaged, ulcers, lumps and other changes can be formed, and the lesions are mostly dominated by one side of the wall, the passive expansion of the stenosis is poor, and there is a greater resistance to the passage of the endoscope, and the stenosis is serious and often cannot be passed, and the strong insertion of the scope is easy to cause perforation. Treatment measures 1, internal medicine therapy, it is appropriate to eat small meals, chewing, avoiding too cold, too hot and stimulating diet. Psychotherapy and external agents can be given to those who are mentally nervous. Some patients use Valsalva maneuver to push food from esophagus into stomach and relieve retrosternal discomfort. Sublingual nitroglycerin relieves spasmodic esophageal pain, such as rapid esophageal emptying. Prostaglandin E can reduce the resting pressure of the LES in patients with this disease has a certain efficacy. 1978 Weiser et al. first found that the calcium channel blocker nifedipine (nifedipine) 10mg, 4 times a day, several weeks after the symptoms can be relieved, and esophageal dynamics measurements can also be confirmed that the product can reduce the resting pressure of the LES, the amplitude of esophageal contractions and transient contractions and frequency, and also improve the food from the esophagus to the stomach. It also improved food emptying in the esophagus. Subsequently, the calcium channel blockers isoptin and diltiazem have been found to have a similar effect on LES resting pressure, but the latter is less clinically effective. Extreme esophageal dilatation should be used every easy bedtime for esophageal drainage irrigation, and fasting, infusion, timely correction of water, electrolyte and acid-base metabolic disorders. 2.Esophageal dilatation therapy Apply balloon or probe strip dilatation to relax the connection between esophagus and stomach. Under fluoroscopy or gastroscopy, insert the air bag with guide wire as the guide through the mouth, so that the guide wire enters into the mouth of the stomach, and the air bag is fixed in the connection between the esophagus and the stomach, and inject gas or liquid, and stop injecting gas or liquid when chest pain occurs. It was left in place for 5 to 10 minutes and then removed. After 5 years of follow-up after one treatment, the effective rate was 60%～80%. The effective standard is due to the disappearance of the lower difficulty, can resume normal diet. However, the incidence of esophageal rupture in this treatment is 1%～6%, so it should be operated with caution. Surgery: There are many surgical methods. Heller’s lower esophageal myotomy is the most commonly used. If the esophagus is overexpanded, the esophagus has severe fibrous hyperplasia at the diaphragmatic hiatus, or the lower esophagus is severely reduced, it is advisable to perform cardia and lower esophagus resection and reconstruction. The symptomatic improvement rate after surgery is about 80%～85%, but complications such as esophageal mucosal rupture, hiatal hernia and gastroesophageal reflux may occur. Complications 1, respiratory complications occur in about 10% of patients, more obvious in children, because of reflux vomiting aspiration pneumonia, bronchodilatation, lung abscess and pulmonary fibrosis is the most common. Cancer is reported to be combined with esophageal cancer in 2%~7% of patients, especially in those who have been sick for more than 10 years, with obvious esophageal dilatation and serious retention. 3.Esophagitis due to food retention in the esophagus of achalasia, endoscopy can see esophagitis and its caused by mucosal ulcers, ulcers can be bleeding, a few spontaneous perforation, esophagotracheal fistula. Candida infection may be combined in those who are debilitated or have received antibiotic therapy or are granulocytopenic. White spots are seen on the inflamed mucosa in endoscopy. Specimen smears and biopsy can confirm the diagnosis. Treatment should be firstly dilatation to relieve esophageal retention, and those who cannot tolerate strong dilatation can use suction drainage to keep the esophagus emptying, and apply antibiotics at the same time. 4, other complications due to loss of relaxation of esophageal dilatation, so that the lumen of the increased tension, the occurrence of diaphragmatic dilatation diverticulum complications, can be dealt with at the same time with the loss of relaxation of the treatment. Joint complications similar to rheumatoid arthritis occur in a small number of patients and may resolve with treatment of achalasia. Prevention: Eat small, frequent, and chewy meals, and avoid excessively cold, hot, and irritating diets. Psychotherapy and externalizing agents may be given to those who are mentally nervous. Valsalva maneuver is used in some patients to encourage food to pass from the esophagus into the stomach and relieve retrosternal discomfort. Sublingual nitroglycerin can relieve esophageal spasmodic pain, such as rapid esophageal emptying.