Gastric tuberculosis

　　Gastric tuberculosis is mainly caused by swallowed tuberculosis bacteria, and the bacteria侵入the gastric wall through the blood, etc. The specific causes and mechanisms are described as follows.

　　I. Causes of Gastric Tuberculosis

　　Primary gastric tuberculosis is very rare, mostly secondary to pulmonary, peritoneal, skeletal, and intestinal tuberculosis. The incidence of gastric tuberculosis is much lower than that of intestinal tuberculosis, and the reason may be:

　　1. The gastric mucosa is relatively intact.

　　2. There are fewer lymphoid follicles in the gastric wall.

　　3. The stomach empties quickly, and the time the swallowed tuberculosis bacteria remain in the stomach is short.

　　Gastric tuberculosis often coexists with other gastric diseases, such as gastric ulcer and gastric cancer. The possible pathways for tuberculosis bacteria to enter the stomach may include:

　　1. The swallowed tuberculosis bacteria directly invade the gastric mucosa.

　　2. Tuberculosis bacteria侵入 the gastric wall through the blood.

　　3. Tuberculosis bacteria侵入 the gastric wall through the lymphatic system.

　　4. Direct extension from lymphatic tuberculosis near the stomach or peritoneal tuberculosis to the stomach.

　　Second, the pathogenesis of gastric tuberculosis

　　1. Onset site:Gastric tuberculosis mostly occurs in the small curvature side of the pylorus and pre-pyloric area, with a few occurring in the gastric body or greater curvature.

　　2. Pathological type:

　　(1) Ulcerative type:This type is the most common, accounting for about 80%. Ulcers can be solitary or multiple, most are shallow and small with irregular edges, and grayish nodules can be seen at the base. There are also larger ulcers that can reach the muscular layer and serosa, forming penetrating ulcers or fistulas, but acute perforation is rare. A few patients may have ulcers that invade larger blood vessels, causing massive hemorrhage. The formation of ulcer scars can lead to pyloric obstruction.

　　(2) Mass type:Formed by inflammatory hypertrophy or proliferative lesions, which can also form masses or large nodules due to adhesion between the stomach and surrounding organs. Pyloric lesions are prone to obstruction.

　　(3) Miliary nodule type:It is part of systemic miliary tuberculosis, and scattered miliary nodules can be seen in all layers of the gastric wall.

　　(4) Inflammatory proliferative (diffuse infiltrative) type:The lesions often involve all layers of the gastric wall, so the gastric wall thickens, and the mucosa shows polypoid hyperplasia.

　　3. Tissue morphology:The lymph nodes near the pathological lesions often show enlargement and caseous necrosis. Pathological tissue examination may show typical caseous granulomas, usually located in the mucosa and submucosa, rarely involving the muscular layer. Acid-fast staining of tissue sections can detect acid-fast bacilli.

　　Gastric tuberculosis can cause bleeding, vomiting coffee-like substances, and may be accompanied by anorexia and weight loss. Gastric tuberculosis is prone to invade the gastric wall tissue in the pylorus and pre-pyloric area, and when the tuberculous granuloma proliferates to form a mass or large nodule, it can easily cause pyloric obstruction, so the vomit may contain leftover food and acid liquid and mucus, but not bile. Due to malnutrition and gastric bleeding, anemia signs may often be present.

　　Gastric tuberculosis is very rare, and the main focus is on preventing the occurrence of tuberculosis. The specific preventive and control measures are described as follows.

　　1. Avoid the decline of gastric function and the conditions leading to diseases.

　　2. Avoid eating cold, spicy, and刺激性 foods, avoid overeating and drinking, avoid smoking and drinking, in order to avoid stimulating and destroying the function of the gastric mucosa.

　　3. Avoid staying up late, do moderate exercise, and strengthen physical fitness.

　　4. Pay attention to vaccination to avoid infection with tuberculosis bacteria.

     Gastric tuberculosis can be detected through serological, fecal occult blood, and gastric juice analysis to detect the pathogen, and endoscopy is the main examination method. The specific method is described as follows.

　　1. Hematological examination:There is often mild anemia, blood sedimentation can increase, and tuberculosis antibodies can be detected in serum.

　　2. Fecal occult blood test:It can show a positive reaction.

　　3. PPD skin test:It often shows a positive or strong positive reaction.

　　4. Gastric juice analysis:It often decreases, and some patients have no lack of gastric acid.

　　5. Endoscopic biopsy:Thin section acid-fast staining is positive, with caseous granuloma.

　　6. Barium meal X-ray examination:Gastric tuberculosis does not have specific X-ray signs and can manifest as shadowing, filling defects, narrowing and deformation of the gastric antrum, and often involves duodenal involvement and pyloric obstruction. The gastric mucosa is rough, the gastric wall is still soft, but there are also cases of rigid gastric wall, and a few even present as leather-like stomach. These signs are difficult to distinguish from gastric ulcer, gastric cancer, gastric malignant lymphoma, and gastric Crohn's disease, etc.

　　7. Endoscopy:The main method for diagnosing gastric tuberculosis. It is still difficult to differentiate gastric tuberculosis from gastric ulcer or gastric cancer under endoscopy. However, if the following conditions are found in histological examination, it is helpful for the diagnosis of tuberculosis:

     10. Caseous granuloma.

     9. Thin section acid-fast staining or culture of biopsy material shows the presence of Mycobacterium tuberculosis.

     8. Polymerase chain reaction (PCR) detection shows that the DNA of Mycobacterium tuberculosis is positive. If the lesion is located in the muscular layer and has not destroyed the mucosa, it is easy to misdiagnose it as a smooth muscle tumor during endoscopy. For submucosal lesions, if the tissue taken during biopsy is too shallow, it may also show negative results.

　　Tuberculosis patients with gastritis should increase the intake of foods rich in protein, vitamins, and calcium. The specific diet is described as follows.

　　1. Increase the intake of foods rich in high-quality protein:The repair of tuberculosis lesions requires a large amount of protein. Providing an adequate amount of high-quality protein helps the formation of immune globulins in the body and corrects anemia symptoms. It is advisable to eat more lean meat, fish, shrimp, eggs, and soy products. Ensure that 80 to 100 grams of protein are consumed daily, and high-quality protein should account for more than 50%.

　　2. Increase the intake of foods rich in calcium:Calcification during the recovery of tuberculosis requires a large amount of calcium. Milk and dairy products contain a rich amount of casein and a significant amount of calcium, which is beneficial for the calcification of tuberculosis foci. Therefore, encouraging tuberculosis patients to drink more milk is the best choice for calcium supplementation, and drinking 250 to 500 grams of milk daily can meet the body's calcium needs. Foods high in calcium include bone soup, shellfish, and soy products, etc.

　　3. Appropriately increase the intake of vitamins:Vitamin C helps the body recover health, vitamin B1 and vitamin B6 can reduce the adverse reactions of antituberculosis drugs, vitamin A can enhance the resistance of epithelial cells, and vitamin D can help absorb calcium. Fresh vegetables, fruits, fish and shrimp, animal internal organs, and eggs are rich in vitamins.

　　4. Regularly consume iron-rich foods:Foods rich in iron have a blood-building effect, such as animal liver, lean meat, egg yolks, green leafy vegetables, edible mushrooms, etc. Pork ribs contain direct blood-building ingredients, and the medullary cavity of pork ribs accumulates a large amount of blood-building components. Drinking pork bone soup is also beneficial to tuberculosis patients.

　　Antituberculosis drug treatment should be the first choice for gastric tuberculosis, and surgical treatment can be considered when complications occur or diagnosis is difficult.

　　1. Antituberculosis Drug Treatment:Antituberculosis drugs are effective for the majority of gastric tuberculosis patients. The commonly used treatment plan is isoniazid 300mg and rifampicin 600mg, once a day, orally, for a total of 9 months. It can also be taken once a day for the first 2 months, and then 2 to 3 times a week for the next 7 months. Pyrazinamide, streptomycin, or ethambutol can be added for resistant patients. For mild patients, isoniazid plus ethambutol can be used for 18 to 24 months, with streptomycin added for the first 2 months. Pay attention to monitoring the side effects of the drugs during the medication process. After antituberculosis treatment, ulcerative lesions can heal completely, and pyloric obstruction can also be relieved.

　　2. Surgical Treatment:Surgical indications include pyloric obstruction, acute perforation, localized perforation with abscess or fistula, and massive hemorrhage. Currently, it is advocated that the surgical method should be as conservative and simple as possible. If a gastric resection is required, the Billroth II procedure can be performed, as tuberculosis can invade the duodenum and the Billroth I procedure is not suitable. When it is difficult to judge the nature of the lesion visually during surgery, frozen section examination should be performed to avoid misdiagnosis as malignant tumor and extensive resection, or considering the tumor as advanced and giving up surgery. Antituberculosis drugs should be used before and after surgery to prevent the spread of the lesion.

　　Timely diagnosis and treatment of stomach tuberculosis are effective, and antituberculosis treatment results in a good prognosis.