Duodenal tuberculosis

　　First, Etiology

　　Due to the short stay time of food in the duodenum and the action of gastric acid, tubercle bacilli are generally not easy to grow and reproduce in the duodenum. However, when the patient's resistance is low and they are exposed to a large amount of tubercle bacilli, as reported abroad, 10% to 50% of patients with active pulmonary tuberculosis may develop infection. The cause is considered to be related to the following factors:

　　1. The tubercle bacillus circulates through the blood or lymphatic system to the submucosa or muscular layer of the duodenal wall, forming a tuberculosis focus, and then develops to invade the mucosa and serosa layer.

　　2. The tuberculosis focus of adjacent tissue or organ directly invades and penetrates the duodenal wall.

　　3. Sputum containing tubercle bacilli is inhaled or swallowed, and the tubercle bacilli remain in the duodenum, invade the mucosa and submucosa to cause infection. In addition, due to the rich blood supply of the duodenum, it also creates conditions for the infection of tubercle bacilli.

　　4. The biliary tract system may also be another route of infection, such as the tubercle bacilli of hepatic tuberculosis can reach the duodenum through the extrahepatic bile duct to cause infection.

　　The main sites of duodenal tuberculosis are mainly in the horizontal part of the duodenum, followed by the descending part. Tuberculosis in the duodenal ampulla often invades the stomach.

　　Second, Pathogenesis

　　Duodenal tuberculosis, like other gastrointestinal tuberculosis, often occurs first in the submucosal tissue, and invasion of the mucosa forms ulcers of varying sizes and depths. A few are polypoid or large nodular masses. Microscopically, the lesion is caseous necrosis and typical tuberculosis granuloma. Pathologically, it can mainly be divided into 3 types:

　　1. Inflammatory hyperplastic type:The duodenal mucosa presents with polypoid hyperplasia and shallow ulcers, with fibrous tissue hyperplasia and scar contraction around it. Due to the fusion of enlarged lymph nodes near the lesion, it often leads to incomplete obstruction, even complete obstruction, of the duodenum.

　　2. Ulcerative type:Lesions usually occur first in the submucosal layer, and then invade the mucosal surface, forming ulcers after erosion. Generally, the muscular layer is not involved, and there are often enlarged lymph nodes around the lesion.

　　3. Ulcerative hyperplastic type:Large ulcers with fibrous tissue hyperplasia and scar formation.

　　During the chronic progression of intestinal tuberculosis, various complications may occur.

　　1. Intestinal obstruction:It is the most common complication of the disease, mainly occurring in hyperplastic intestinal tuberculosis. Ulcerative intestinal tuberculosis, due to adhesions of the peritoneum adjacent to the intestinal ulcer, may cause traction, constriction, and compression of the intestinal loops, or due to scar contraction after healing of the intestinal ulcer, may narrow the intestinal lumen and cause obstruction. The obstruction is often chronic and progressive, often partial, with varying degrees of severity, and prolonged duration, which can seriously affect the nutritional status of patients. A few may develop into complete intestinal obstruction.

　　2. Intestinal perforation:The incidence rate is second only to intestinal obstruction, mainly due to subacute or chronic perforation, which can form abscesses in the abdominal cavity and lead to intestinal fistulas after rupture. Acute perforation is less common, often occurring in the highly dilated segments of the intestine near the obstruction, or seen in obstructive intestinal obstruction caused by multiple intestinal stenoses.

　　3. Other:There may be peritonitis, intestinal adhesions, intussusception, and contractile diverticula, etc.

　　Duodenal tuberculosis lacks specific clinical manifestations, and the disease is more common in young and middle-aged adults, with a peak incidence between 20 to 40 years old, especially in female patients. The disease is mainly transmitted through the oral route, with an insidious onset, slow progression, long course, and early symptoms are not obvious. The clinical manifestations are as follows:

　　1. Symptoms of duodenal obstruction:The most common symptom of duodenal tuberculosis is abdominal pain and vomiting, often presenting with a feeling of fullness or discomfort in the upper abdomen after eating, nausea, vomiting, and a decrease in upper abdominal pain or fullness after vomiting. Gupta et al. reported on 30 cases of duodenal tuberculosis, of which 22 presented with gastric duodenal obstruction; Cao Tao et al. reported on 16 cases, of which 13 presented with gastric duodenal obstruction.

　　2. Dyspeptic symptoms:Manifested as discomfort in the upper abdomen, abdominal distension, nausea, and the ineffectiveness of antacid treatment.

　　3. Symptoms of tuberculosis intoxication:Some patients may have low fever, night sweats, fatigue, anorexia, and weight loss.

　　4. Other symptoms:A few patients may present with upper gastrointestinal bleeding as the initial manifestation, and some patients may develop internal fistulas between adjacent tissues or organs such as the renal pelvis and bile ducts.

　　5. Signs and symptoms of duodenal tuberculosis:The main symptoms include upper abdominal tenderness, mass in the upper right abdomen, positive tympany, and superficial lymphadenopathy.

　　Preventive measures are the fundamental approach to preventing and treating tuberculosis. Emphasis should be placed on the detection of extraintestinal tuberculosis, especially the early diagnosis of pulmonary tuberculosis and active antituberculosis treatment, to quickly turn sputum bacteria negative and avoid intestinal infection caused by swallowing sputum containing bacteria. It is essential to emphasize health education related to tuberculosis. Patients should be educated not to swallow sputum, maintain smooth defecation, strengthen health supervision, advocate the use of communal chopsticks for meals, and pasteurize milk.

　　For patients with simple duodenal tuberculosis who have a good general condition, laboratory tests usually show no abnormalities. With a long course, there may be an increased erythrocyte sedimentation rate and decreased hemoglobin, which are the main positive findings of laboratory tests. There may also be positive tuberculin skin test, positive tuberculosis antibody, and positive occult blood in the stool in cases of hemorrhage.

　　1. X-ray manifestations

　　For patients suspected of having duodenal tuberculosis, an upper gastrointestinal barium meal examination is required. In patients with proliferative duodenal tuberculosis, common X-ray manifestations are varying degrees of luminal narrowing, mostly caused by extraluminal lymph node enlargement, which can cause a 'knife-cut' sign at the obstruction site or enlargement of the duodenal loop, presenting similar symptoms to superior mesenteric artery syndrome. The proximal intestinal lumen is dilated, and a few patients present with luminal narrowing, mucosal folds showing polypoid changes, and ulcerative patients may have ball or postball ulcers. Ulcers are usually small and not easily visible, but are often accompanied by thickening of the duodenal mucosal folds, luminal spasm, and narrowing.

　　2. Abdominal ultrasound and CT scan

　　For patients with severe conditions, especially those with lymph node enlargement near the duodenal cavity, an abdominal mass can be found in the upper abdomen.

　　3. Endoscopic examination

　　1. Gastroscopy:Narrowing of the lumen can be seen, endoscopy is difficult, the mucosa in the narrowed area is congested and edematous, some patients may have erosion and ulceration, the proximal intestinal lumen is dilated. Due to the location of tuberculosis granulomas mostly in the submucosal layer, coupled with lumen narrowing, endoscopic biopsy is relatively difficult, and the biopsy results are mostly non-specific inflammatory manifestations. Therefore, in addition to clearly defining the obstruction site, endoscopic examination has little diagnostic significance.

　　2. Laparoscopic examination:Direct observation of the lesion site can be made, and biopsy can be performed for suspicious lesions, avoiding laparotomy, thus having certain value for diagnosis.

　　In addition to conventional treatment, patients with duodenal tuberculosis need to rest in bed and pay attention to the following aspects in diet: a diet high in calories, protein, and vitamins should be provided to correct malnutrition.

　　1. Treatment

　　Treatment objectives:Relieve symptoms, relieve obstruction, improve systemic symptoms, and prevent the occurrence of complications.

　　1. Principles of medical treatment:For early duodenal tuberculosis patients without complications, medical treatment should be administered, which requires early, combined, moderate, regular, and full-course medication.

　　(1) General treatment: Patients need to rest in bed, and a diet high in calories, protein, and vitamins should be provided to correct malnutrition; anticholinergic drugs such as atropine, anisodamine (654-2), and belladonna can be used for abdominal pain; for patients with diarrhea and insufficient intake, fluid and potassium supplementation can be administered to prevent electrolyte imbalance; for those with incomplete duodenal obstruction, gastrojejunal decompression can be performed to relieve symptoms.

　　(2) Anti-tuberculosis treatment: Short-course therapy is often used, generally using isoniazid and rifampicin in combination, with a course of 6 to 9 months; if serious extra-intestinal tuberculosis is concurrent, such as miliary pulmonary tuberculosis and tuberculous meningitis, etc., a combination of three drugs is often required, and one of the following drugs can be added, such as streptomycin, ethambutol, or pyrazinamide. If duodenal tuberculosis is secondary, and the patient has received anti-tuberculosis drug treatment for pulmonary tuberculosis or tuberculosis in other parts in the past, and the tubercle bacillus has developed certain drug resistance to the first-line drugs, second-line drugs should be considered at this time. The medication should be administered in sufficient doses, which is one of the keys to the success or failure of drug treatment. The duration of medication is generally 1 to 1.5 years.

　　2. Surgical Treatment

　　(1) Indications for surgery: For patients who have been treated with internal medicine and have complications, such as complete intestinal obstruction, acute massive hemorrhage in the intestines, acute or chronic intestinal perforation, duodenal fistula, surgical exploration should be performed in principle, one to clarify the diagnosis, and two to treat.

　　(2) Surgical methods: The design of the surgical plan is mainly determined by the condition of the complications. Duodenal ampulla tuberculosis can be treated with partial gastrectomy and resection of the lesion site, followed by gastrojejunal anastomosis, or with pyloroplasty and vagotomy. For lesions that cannot be resected, gastrojejunal anastomosis and other shunt operations can be used. Obstruction above the duodenal papilla below the descending part can be treated with gastrojejunal anastomosis or partial gastrectomy. Obstruction below the duodenal papilla should be treated with duodenal jejunum Roux-en-Y anastomosis above the obstruction site. For patients with internal fistulas, surgical options can be selected according to the condition. Such as nephrectomy, partial resection of the transverse colon, and resection of internal fistulas, etc.

　　(3) Postoperative anti-tuberculosis treatment: Regardless of the type of surgery, routine anti-tuberculosis treatment is required for 6 to 12 months after surgery.

　　2. Prognosis

　　Before the appearance of anti-tuberculosis drugs, the prognosis of intestinal tuberculosis was poor, and the mortality rate was high. After the wide application of anti-tuberculosis drugs in clinical practice, the prognosis of intestinal tuberculosis was greatly improved, especially for mucosal tuberculosis, including intestinal tuberculosis, the efficacy was particularly significant. The prognosis of this disease depends on early diagnosis and timely treatment. When the lesion is still in the exudative stage, it can be completely cured after treatment, with a good prognosis. Rational selection of anti-tuberculosis drugs, ensuring sufficient dose and sufficient course of treatment, is the key to determining the prognosis.