Subdiaphragmatic abscess

　　The infradiaphragmatic peritoneal lymphatic network is rich, so infections are prone to spread to the infradiaphragmatic area. Infradiaphragmatic abscesses can develop secondary to infections in any part of the body. Abdominal infections are often secondary to complications of peritonitis such as organ perforation and inflammation. It is common in acute appendicitis perforation, gastric and duodenal ulcer perforation, and acute inflammation of the liver and gallbladder, which often lead to right infradiaphragmatic infections. Extra-peritoneal infradiaphragmatic abscesses usually come from the rupture of liver abscesses. According to statistics, about 25-30% of infradiaphragmatic infections will develop into abscesses, and the rest can usually be resolved spontaneously, which is due to the strong resistance of the peritoneum in the upper abdomen.
　　The causative pathogens of abscesses are mainly from the gastrointestinal tract, among which Escherichia coli and anaerobic bacteria account for about 40%, streptococcal infections account for 40%, and staphylococcal infections account for about 20%. However, most are mixed infections.

　　The late complications of an abscess under the diaphragm are as follows:

　　1. Chest infection: Subphrenic infection can cause reactive pleural effusion, or spread to the pleural cavity through the lymphatic pathway, causing pleurisy; it can also penetrate into the pleural cavity, causing empyema. The patient's main symptoms are acute chest inflammation and effusion, often with high fever, chest pain, chest tightness, tachypnea, cough, loss of appetite, malaise, and fatigue. Physical examination may show tachypnea, the affected side of the chest wall is slightly full, respiratory movement is weakened, vocal cord vibration is weakened, percussion shows dullness, respiratory sound is weakened or disappears, and the trachea and mediastinum are shifted to the opposite side. The signs of localized empyema are often not obvious or there may be local signs at the lesion site, and chest puncture can also be performed for examination.

　　2. Gastrointestinal bleeding and fistula: As the abscess can erode the gastrointestinal tract wall, it can cause recurrent gastrointestinal bleeding, intestinal fistula, or gastric fistula. The patient may present with dizziness, palpitations, nausea, thirst, dim vision, or fainting; the skin appears pale and moist due to vasoconstriction and insufficient blood perfusion; pressing on the nail bed reveals pallor, and it does not recover over time. There is poor venous filling, and superficial veins often collapse. The patient feels fatigue and weakness, and can further develop mental depression, restlessness, or even obtundation and confusion.

　　3. Anemia, characterized by dizziness, tinnitus, headache, insomnia, dreaming, memory loss, lack of concentration, pale skin and mucous membranes, etc.

　　4. Sepsis, even septic shock, which may endanger life.

　　⒈ After peritonitis or abdominal surgery, the condition had temporarily improved, but a remittent fever appeared several days later, accompanied by chills, sweating, rapid pulse, and other symptoms of infection and poisoning.

　　⒉ Persistent dull pain in the upper abdomen on the affected side, accompanied by radiation pain to the shoulder and hiccups.

　　⒊ Local tenderness and percussion pain, edema of the intercostal skin in the corresponding area.

　　The pus accumulation in the subphrenic space, under the diaphragm, the transverse colon, and the omentum, is commonly referred to as an abscess under the diaphragm. An abscess under the diaphragm can occur in one or more spaces. It often occurs as a complication of peritoneal conditions such as organ perforation, inflammation, and peritonitis. An abscess under the diaphragm can originate from an acute purulent infection or from pathogenic bacteria transferred through blood flow or lymphatic vessels from a distant primary infection source. It is often due to the necrosis and dissolution of inflamed tissue under the action of toxins or enzymes produced by bacteria, forming a pus cavity. The pus consists of exudate, necrotic tissue, pus cells, and bacteria. It is the formation of a reticular framework of fibrin in the pus that confines the lesion to a local area, along with congestion, edema, and leukocyte infiltration around the pus cavity. Prompt treatment is necessary for an abscess under the diaphragm, as the treatment outcome is good. Patients who have improved after treatment for acute peritonitis or inflammatory diseases of abdominal viscera, or those who develop fever and abdominal pain several days after abdominal surgery, should be considered for this condition and further examination should be conducted. The abscess under the diaphragm is commonly seen as a complication of acute appendicitis perforation, gastric and duodenal ulcer perforation, and acute inflammation of the liver and gallbladder, but the initial stage of the lesion or a small abscess is often difficult to confirm, requiring repeated examinations and careful observation to detect it. In cases of larger abscesses, early surgical treatment should be considered.

　　Even if the treatment is effective, an abscess under the diaphragm still has an approximately 5% mortality rate to this day, so prevention should be noted.

　　1. White blood cell count and differential count: The total white blood cell count and neutrophils are significantly increased, with nuclear left shift.

　　2. Bacteriological culture

　　(1) Blood culture: Blood culture should be performed for patients with severe systemic toxic symptoms, and a few may be positive.

　　(2) Pus culture: When diagnostic puncture is performed and the aspirated fluid is pus, bacterial culture and drug sensitivity test should be performed to guide the use of antibiotics in clinical practice.

　　3. Red blood cell and hemoglobin monitoring: In the elderly, persistent fever can cause a slight decrease in hemoglobin.

　　4. X-ray examination: Chest and abdominal fluoroscopy and radiography: The diaphragm on the affected side is elevated, and respiratory movement is weakened or absent; the costodiaphragmatic angle on the affected side is blurred or there is obvious pleural effusion; there is a gas-liquid interface under the diaphragm. Barium meal examination: On the left side, an abscess under the diaphragm can be seen where the stomach is compressed and displaced.

　　5. B-ultrasound shows a liquid level on the affected side under the diaphragm, which is helpful for the diagnosis and accurate positioning of the abscess. Diagnostic puncture can be performed under B-ultrasound guidance. The pus fluid is aspirated for bacterial culture and drug sensitivity test.

　　6. CT scan can determine the location, size, and relationship of the abscess with surrounding organs, with a correct diagnosis rate of 90% for abdominal abscesses, especially suitable for those who are overweight, have intestinal bloating, or have abdominal drainage tubes, and are not suitable for ultrasound examination.

　　The dietary principles for patients with an abscess under the diaphragm: low-fat, high-nutrition, high-vitamin, and easy-to-digest diet.

　　The best food for nourishing the liver is grains, such as glutinous rice, black rice, sorghum, and millet; followed by dates, longan, walnuts, chestnuts; and also meat and fish such as beef, pork stomach, crucian carp, etc., which also have a health-preserving effect on the liver.

　　1. Soybeans and soy products contain a wealth of protein, calcium, iron, phosphorus, vitamin B, moderate amounts of fat, and a small amount of carbohydrates, which are very beneficial for liver repair.

　　2. Seafood such as whitebait, yellow croaker, silver carp, and shellfish such as oysters and crabs can enhance the immune function, repair damaged tissue cells, and not be invaded by viruses. However, proper selection and cooking are necessary; otherwise, food poisoning may occur. Steaming should be heated above 100 degrees for more than half an hour. If allergic to seafood, it should be avoided, and more mushrooms, tremella, kelp, and nori can be eaten.

　　3. Watermelon has the functions of clearing heat and detoxifying, relieving irritability and thirst, and diuretic and hypotensive effects. It is rich in a large amount of sugar, vitamins, and protease. Protease can convert insoluble protein into soluble protein.

　　An abscess under the diaphragm originates from infection. If the inflammation is actively treated to gradually dissipate, it can prevent the formation of an abscess. Therefore, semi-recumbent position, gastrointestinal decompression, the selection of appropriate antibiotics, and the strengthening of supportive therapy are all treatments to prevent the formation of an abscess. Once an abscess forms, it must be drained surgically as soon as possible to prevent the abscess from penetrating the diaphragm to form pleurisy, or breaking into the abdominal cavity to cause secondary peritonitis, or piercing nearby blood vessels to cause massive hemorrhage, etc. The position of the abscess must be determined before surgery to select the incision and approach for drainage. The surgery should avoid contamination of the pleural and abdominal cavities, and provide blood transfusion and other supportive treatments to ensure that the patient can smoothly go through the surgery and recover early.

　　Non-surgical treatment for patients with subphrenic abscesses:

　　Principles of treatment for subphrenic abscesses: 1. Early application of high-dose antibiotics to control infection, strengthen supportive therapy, correct water and electrolyte imbalances, and correct acid-base balance. The choice of antibiotics is based on the bacterial culture of the pus and the results of drug sensitivity tests. Before the results of the culture are obtained, broad-spectrum antibiotics should be chosen. Subphrenic infections are mainly caused by Gram-negative bacilli, and commonly used antibiotics include gentamicin, ampicillin, and cephalosporins. In treatment, attention should be paid to the combined use of antibiotics against anaerobic bacteria (metronidazole); 2. After the abscess forms, it is generally necessary to surgically incise and drain the pus or puncture and place a catheter for drainage, which cannot be replaced by any medication. The following surgical procedures should be selected according to the size and location of the abscess: percutaneous puncture and catheter drainage; subxiphoid operation for drainage; drainage through the posterior腰部; drainage through the lateral chest.

　　Antibiotic treatment for subphrenic abscesses: should begin before drainage.

　　(1) Principles of medication: Early treatment can be based on empirical medication, and adjustments can be made after the results of bacterial culture and drug sensitivity tests are obtained; combined use of antibiotics against anaerobic and aerobic bacteria; intravenous administration until the patient's body temperature and peripheral blood white blood cell count return to normal.

　　(2) Common antibiotics: Aminoglycosides are highly effective against the most common enterobacteria in abscesses; aztreonam, imipenem (imipenem), α-carboxythiophenylpenicillin, clavulanic acid, and fluoroquinolones, or second and third-generation cephalosporins, can cover Gram-negative bacilli; metronidazole and clindamycin (chlorocephalosporin) are commonly used against anaerobic bacteria, with similar efficacy, but the former is cheaper and more widely used in China; imipenem (imipenem), α-carboxythiophenylpenicillin, and others have both aerobic and anaerobic antibacterial effects and can sometimes be used alone. For a few with evidence of enterococci, ampicillin is usually added conventionally.