Secondary purulent peritonitis

　　Common causes of secondary peritonitis include acute inflammation of abdominal organs, such as acute appendicitis, acute cholecystitis, purulent inflammation of female reproductive organs or postpartum infection, strangulated intestinal obstruction, intestinal mesenteric thrombosis leading to intestinal necrosis, and chemical peritonitis secondary to acute hemorrhagic necrotic pancreatitis, among which acute appendicitis is the most common, accounting for about 40%. The common causes are as follows:

　　1. Acute perforation
　　Acute perforation of hollow organs occurs on the basis of pre-existing lesions, such as gastric and duodenal ulcers, appendicitis, cholecystitis, typhoid fever, hemorrhagic necrotic enteritis, amebic colitis, ulcerative colitis, Meckel diverticulum, and necrotic perforation of gastrointestinal tumors.

　　2. Organ rupture
　　Blunt or penetrating abdominal trauma can cause rupture of the gastrointestinal tract, bile duct, and bladder. The leakage of gastric juice, bile, or urine is a chemical irritation to the peritoneum, which can lead to secondary infection later; the leakage of feces contaminates the peritoneal cavity, leading to severe purulent peritonitis.

　　3. Surgical contamination
　　It is often caused by improper operation, leading to the spread of the original abdominal infection focus, or injury to the intestines, bile duct, pancreatic duct, or ureter, with extrusion of contents, or the occurrence of intestinal fistula, anastomotic fistula, biliary-pancreatic fistula, and accidental injury to the extrahepatic bile duct during cholecystectomy.

　　The complications of secondary purulent peritonitis can be divided according to the timing of their occurrence. The specific complications are as follows;
　　1. Early complications Hypokalemia, shock, disseminated intravascular coagulation (DIC), intestinal obstruction, acute renal failure, adult respiratory distress syndrome, respiratory failure, sepsis.
　　2. Late complications Formation of intra-abdominal abscesses (pelvic, subdiaphragmatic space, mesenteric interstices, etc.).

　　The clinical manifestations of secondary purulent peritonitis are complex, and common symptoms include the following aspects.

　　1. Abdominal pain and distension:It is the most important and common symptom. It can present as severe localized or diffuse abdominal pain, the location of which is related to the etiology and course of the primary disease, the nature of inflammation (localized or diffuse), and the patient's reactivity. Abdominal pain usually occurs suddenly, persists, and intensifies with deep breathing, coughing, or changing body position. Patients often prefer to assume a flexed position and refuse to move.

　　2. Nausea and vomiting:It is the earliest and most common symptom. Due to the stimulation of the peritoneum, reflex nausea and vomiting occur, and the vomit is mostly gastric contents, with varying durations. When paralytic ileus occurs, the vomit often contains yellow-green bile, even brownish fecal matter, and is accompanied by an unpleasant odor.

　　3. Body temperature and pulse:In the early stage of acute peritonitis, patients often have symptoms of collapse, with body temperature that can be normal or slightly low, which then gradually increases. The increase in body temperature is often parallel to the increase in respiration and pulse, and may be accompanied by chills, which is often a sign of sepsis. In elderly and weak patients, body temperature may not increase, and the pulse may accelerate. If the pulse is fast, the body temperature may反而 decrease, which is one of the signs of deterioration of the condition.

　　4. Others:During the onset of acute peritonitis, symptoms such as anorexia and constipation may also occur. As the condition progresses, symptoms of dehydration such as excessive sweating, dry mouth, sunken eye sockets, dry skin, and decreased urine output may appear. Shallow and rapid breathing often suggests stimulation of the diaphragm, restricting its movement, and may be accompanied by hiccups and shoulder pain. In addition, other clinical manifestations related to the etiology may also occur during the onset of acute peritonitis.

　　The vast majority of purulent peritonitis is secondary. If the primary disease focus causing peritonitis can be treated correctly in a timely manner, the incidence of secondary purulent peritonitis can be reduced to the minimum. For example, the focus can be removed at the early stage of acute appendicitis or acute cholecystitis. Early relief of intestinal obstruction and timely repair of gastrointestinal perforations can greatly reduce the chance of peritonitis. When performing gastrointestinal surgery, it is necessary to avoid the leakage of its contents and prevent leakage at the suture site of the gastrointestinal tract to minimize or prevent the occurrence of postoperative peritonitis.

　　The diagnosis of secondary purulent peritonitis relies not only on clinical manifestations and signs but also on laboratory tests and auxiliary examinations, which are indispensable. The main examination methods used in clinical practice are as follows:

　　1. White blood cells
　　The total count and neutrophils are significantly increased, and in severe infections, neutrophils contain toxic granules and nuclear left shift; urine is often concentrated, resulting in increased specific gravity, and sometimes urinary ketones are positive. Abnormal conditions may also result in protein and casts in the urine.

　　2, Peritoneal puncture or cul-de-sac puncture
　　It is still widely recognized as one of the most valuable diagnostic methods for peritonitis, as it can understand the appearance and smell of ascites, and perform cell counting. Smears and bacterial cultures, and if necessary, the measurement of amylase content, are of great help to the diagnosis.

　　3, Abdominal X-ray examination
　　Examine for free air, focusing on the subdiaphragmatic lucency area, or observe the shape of the intestinal loops and the liquid level. If free subdiaphragmatic air or extragastrintestinal gas accumulation is found, it often suggests gastrointestinal perforation.

　　4, B-ultrasound examination
　　An intraperitoneal abscess is displayed as a hypoechoic area on the B-ultrasound, and it can also be punctured and aspirated under the guidance of B-ultrasound localization. During acute peritonitis, due to intestinal distension, it affects the ultrasound display, so the diagnostic value of B-ultrasound for intraperitoneal intestinal abscesses is not great.

　　5, Digital rectal examination or pelvic examination
　　Digital rectal examination or pelvic examination can find that the rectum, uterus, or bladder depression is significantly tender, and sometimes there can be a feeling of bulging, hardness, or fluctuation, indicating inflammation or abscess accumulation.

　　6, Laparoscopic examination
　　For patients with atypical clinical symptoms and unclear diagnosis of peritonitis, laparoscopic examination can be used to assist in diagnosis, and laparoscopic examination should not be used for patients with emergency surgical exploration indications.

　　Absolute NPO (NPO stands for 'nothing by mouth') is required after surgery for secondary purulent peritonitis. The timing of eating and the choice of food depend on the type of surgery. Generally, eating can be resumed after the intestinal peristalsis (or flatus) recovers and with the consent of the physician. It is recommended to start with some plain water, and if there is no choking or other discomfort, one can start with some liquid and light food, and then adopt a small and frequent meals approach to obtain nutrition. 

　　The treatment of secondary purulent peritonitis includes non-surgical treatment and surgical treatment. Non-surgical treatment should be carried out under strict observation and preparation for surgery; the surgical method for acute peritonitis is based on the principles of treatment and basic steps. The specific treatment methods are as follows:

　　One, Non-surgical treatment
　　1, NPO (NPO stands for 'nothing by mouth'): It can reduce gastrointestinal contents and secretions, thereby reducing the amount of intestinal contents entering the peritoneal cavity, which helps control infection.
　　2, Gastrointestinal decompression: It can reduce gastrointestinal distension, improve blood supply to the gastrointestinal wall, reduce the amount of gastrointestinal fluid leaking into the peritoneal cavity through gastrointestinal perforations, and is conducive to promoting the recovery of gastrointestinal motility.
　　3, Fluid replacement: Acute diffuse peritonitis patients may have a large amount of fluid in the peritoneal cavity, around the peritoneum, in the viscera, and in the gastrointestinal tract, which can reach more than 4000ml within 24 hours. Clinically, the need for fluid in patients is often underestimated, and it is necessary to correct dehydration and acid-base imbalance through intravenous fluid and blood transfusions; for severe or advanced patients, more plasma and whole blood should be administered to supplement hypoproteinemia and anemia caused by the large amount of plasma exudation in the peritoneal cavity. The standard for adequate fluid replacement in the treatment of acute peritonitis is that the patient's peripheral circulation improves, urine output increases (more than 30ml per hour), heart rate decreases, and mental state tends to stabilize.
　　4. Treatment with antimicrobial drugs: The selection of antibiotics cannot be separated from the estimation of the pathogenic bacteria. In suspected cases of abdominal infection, an immediate abdominal puncture or lavage should be performed, and the abdominal fluid should be taken for Gram staining examination to preliminarily determine the presence and type of pathogenic bacteria. What is more important is to culture the abdominal fluid for aerobic and anaerobic bacteria and determine their sensitivity to antibiotics.
　　5. Combined use of antibiotics: It can achieve synergistic effects and can control peritonitis faster and more effectively. The combined use of aminoglycoside antibiotics with penicillin or cephalosporins for intra-abdominal infection is also widely used. The course of antibiotic treatment for peritonitis patients should be longer, generally stopping medication 1-2 weeks after the body temperature drops, clinical symptoms improve, and local focus of disease is controlled.

　　Second, surgical treatment
　　1. Clearing the focus of disease and controlling the source of contamination: Simple suture repair is used for those who do not need to remove the focus of disease to control infection and clear the source of contamination, such as iatrogenic perforation during colonoscopy and early traumatic gastrointestinal perforation or certain duodenal perforations, small intestinal typhoid perforations, which can be treated with simple suture repair without resection of the diseased part; For infected foci such as purulent appendicitis, gallbladder perforation, and intestinal segment necrosis, surgical resection is the most basic principle of treatment.
　　2. Reducing abdominal contamination: Abdominal debridement: The purpose of the operation is to clear the contaminated substances conducive to bacterial growth, thereby reducing residual infection and preventing abscess formation; Intraoperative abdominal lavage: Experimental research and clinical observations have proved that lavaging the abdomen with normal saline during surgery can improve the prognosis of peritonitis.
　　3. Treatment of residual infection and prevention of intra-abdominal abscess formation: Postoperative abdominal lavage: The role of postoperative abdominal lavage is to continue to clear residual infection, further reduce the total number of bacteria in the abdomen, and prevent the absorption of toxins. There are many methods, the most common method is to place an inflow pipe under each side of the diaphragm, and place an outflow pipe on both sides of the pelvis, the flushing fluid mostly uses normal saline, lactic acid Ringer's solution, and dialysate, etc.; Abdominal drainage surgery: It is necessary to keep the drainage tube unobstructed and prevent the risk of reverse infection and intestinal fistula or massive hemorrhage caused by long-term compression.