Bacterial dysentery

　　1. Etiology
　　(1) Pathogen: Shigella bacteria belong to the genus Shigella of the family Enterobacteriaceae, which are Gram-negative bacilli. According to different antigenic structures, they are divided into four groups: Shigella dysentery bacillus, Flexner dysentery bacillus, Bory dysentery bacillus, and Sonne dysentery bacillus. Each type of Shigella releases endotoxins after death and lysis. The endotoxins released by various types of Shigella are the main pathogenic factors.
　　(2) Source of infection: Patients and carriers.
　　(3) Transmission route: Gastrointestinal transmission.
　　(4) Susceptible population: The general population is susceptible, and immunity can be obtained after the disease, but the duration is short and recurrent infection is easy.
　　(5) Epidemic characteristics: Bacterial dysentery occurs throughout the year, but it is more common in summer and autumn.
　　2. Pathogenesis When Shigella bacteria enter the stomach, they are easily killed by stomach acid. The bacteria that are not killed reach the intestines, invade the mucosal epithelial cells of the colon, and then enter the lamina propria through the basement membrane to continue proliferation, lysis, release endotoxins, and exotoxins, causing local inflammatory reactions and systemic toxemia. Toxic dysentery is an abnormal and strong reaction of the body to a large amount of pathogenic bacterial toxins, manifested as acute microcirculatory disorders and紊乱 of cell metabolic function.
　　3. Pathology Acute bacterial dysentery lesions can affect the entire colon, especially the sigmoid colon and rectum, presenting as a diffuse fibrin exudative inflammation. The intestinal lesions of toxic dysentery are mild, with the prominent pathological changes being cerebral and brainstem edema, and degeneration of nerve cells. Chronic bacterial dysentery shows intestinal mucosal edema and thickening of the intestinal wall, with the formation of scars and polyps.

　　1, The typical symptoms of post-dysentery syndrome first appear as conjunctivitis, which is usually short-lived, often bilateral, and can affect both the bulbar and palpebral conjunctiva. In severe cases, it can affect the entire conjunctiva, accompanied by conjunctival edema, periorbital swelling, and occasionally keratitis and iridocyclitis.

　　2, Arthritis is a major symptom of post-dysentery syndrome, which can occur in any joint, but it is most common in ankle and knee joints, characterized by joint redness, swelling, and pain, often occurring symmetrically, similar to rheumatoid arthritis and ankylosing spondylitis. Severe cases may show effusion in the joint cavity and limited limb movement.

　　3. Urethritis, urgency, frequency, dysuria, may have mucoid secretions, severe cases may have hematuria, pyuria, dysuria, may have mucoid secretions, severe cases may have hematuria, pyuria, accompanied by cystitis, prostatitis, but urine bacterial culture shows no bacterial growth, all of which are typical symptoms of dysentery syndrome.

　　Complications of dysentery can also be accompanied by systemic symptoms of poisoning, showing fever, body temperature up to 39°C, infants and young children may have high fever convulsions, usually without chills, accompanied by anorexia, nausea and vomiting, diarrhea, restlessness, headache, dizziness, etc., which can last for 2 to 3 weeks, severe cases may develop pleurisy, endocarditis.

　　1. Acute shigellosis Acute diarrhea with chills, fever, abdominal pain, urgent need to defecate, and mucous purulent bloody stool; marked tenderness in the whole abdomen and left lower abdomen.
　　2. Acute toxic type shigellosis(Commonly seen in children aged 2 to 7) Sudden onset, sudden high fever, recurrent convulsions, drowsiness, coma, rapid development of circulatory and respiratory failure. Clinically, it is mainly manifested by severe systemic toxic symptoms, shock, and (or) toxic encephalopathy, while intestinal symptoms are mild or absent.
　　3. Chronic shigellosis There are persistent abdominal pain, diarrhea, urgent need to defecate, and mucous purulent bloody stool with dysentery symptoms, and the course of the disease exceeds 2 months.

　　Bacterial dysentery, also known as shigellosis, is an intestinal infectious disease caused by Shigella. The majority of victims are children, followed by adolescents, which has a significant impact on the health of primary and middle school students. Shigellosis is also directly related to the quality of school health environment, health education, and knowledge level. Therefore, the prevention of bacterial dysentery plays an important role in school health work.

　　After adolescent dysentery, symptoms such as fever, abdominal pain, diarrhea, urgent need to defecate, and purulent blood stool may occur. Among them, some people have long-term treatment without improvement, turning chronic, often with abdominal pain and bloody stool, leading to malnutrition and decreased physical fitness. Some people show poisoning symptoms from the beginning, often dying due to rapid onset of shock and respiratory failure for various reasons.

　　Once diagnosed with bacterial dysentery, bed rest should be observed. For those with mild illness, they can eat liquid and semi-liquid foods, but they should not eat cold, greasy, gritty, and stimulating foods; after the condition improves, gradually resume normal diet. If there is a high fever, severe vomiting, dehydration, or obvious systemic symptoms of poisoning, hospitalization for treatment and observation should be arranged, and intravenous fluid therapy and symptomatic treatment should be given.

　　Shigella can be eliminated by sulfonamides and various antibiotics (such as chloramphenicol, streptomycin, and ampicillin, etc.). However, in recent years, there has been an increasing number of Shigella strains that are resistant to these drugs, leading to a decrease in treatment effectiveness. Therefore, doctors choose newer generations of antibiotics and sulfonamides, such as pipemidic acid, flumequine, gentamicin, and so on, for treatment; in addition, drugs such as shigetring, coptis chinensis, and enhanced sulfonamides are also very effective. These drugs are usually selected by doctors according to the local bacterial drug sensitivity at that time, and should be treated thoroughly and in sufficient quantity to prevent chronicization, so it is generally not recommended to take them arbitrarily.

　　For chronic dysentery, in addition to adhering to antibacterial treatment, immunotherapy can generally be used by using the method of subcutaneous injection of multivalent dysentery bacterin, which has a good therapeutic effect. In daily life, patients with chronic dysentery should have a regular life, pay attention to physical exercise to enhance physical fitness; diet should be both nutritious and easy to digest, with less residue to reduce the stimulation of the gastrointestinal tract; for adolescents with a long history of chronic dysentery, it is also advisable to take vitamin C, folic acid, lactobacillus, and Bacillus subtilis tablets in moderation to avoid the suppression of beneficial Escherichia coli in the intestines due to long-term use of antibiotics, which can exacerbate intestinal dysfunction.

　　For toxic dysentery, as long as it is diagnosed early and treated comprehensively in the hospital, most patients can still be cured.

　　According to the characteristics of the school population, mainly comprehensive preventive measures are taken to cut off the transmission route.

　　Firstly, it is necessary to vigorously carry out the patriotic health campaign, improve environmental hygiene, carry out harmless treatment of feces, prevent water source pollution, and eliminate flies.

　　To control the source of infection, it is necessary to make early detection, early diagnosis, and early treatment of acute patients.

　　1. Blood count In acute dysentery, the total white blood cell count and neutrophils increase slightly to moderately, reaching (10-20)×10^9/L. Chronic patients may have anemia.
　　2. Routine fecal examination The appearance of feces is mostly mucous blood, and microscopic examination shows a large number of white blood cells or clumps of pus cells, with a small amount of red blood cells and macrophages.
　　3. Bacterial culture Isolation of Shigella from feces can confirm the diagnosis.
　　4. Immunological examination Immunological methods for detecting bacteria or antigens have the advantages of early detection and rapidity, which can be helpful for early diagnosis of bacteria.

　　To prevent the spread of dysentery, in addition to paying attention to environmental hygiene and personal hygiene, and developing the habit of washing hands before meals and after defecation, there are also the following taboos in diet:

　　①Avoid concentrated meat broths and animal internal organs. They contain a large amount of nitrogenous extracts, such as purine bases and amino acids. Nitrogenous extracts have a stimulating effect on the secretion of gastric juice, and the stronger the juice, the stronger the effect, which increases the burden on the digestive tract. Moreover, in patients with bacterial dysentery, there are intestinal lesions, symptoms such as nausea and vomiting, and poor digestion and absorption.

　　②Avoid coarse fiber and bloating foods. Examples include vegetables like rapeseed, celery, and chives, which have coarse fibers and are difficult to digest, leading to local congestion and edema, and inflammation that is difficult to heal. Milk and sugar, as well as soy products, are also prone to increase intestinal peristalsis, causing bloating.

　　③Avoid刺激性 foods. Examples include fried, baked, salted, and smoked large pieces of fish and meat, which can directly stimulate the intestinal wall, exacerbating intestinal wall damage; these foods are also difficult to digest, causing bloating, fever, and prolonged stay, which can increase the burden on the digestive tract.

　　④Avoid contaminated foods. Unsterilized fruits and vegetables can carry bacteria and are prone to cause poisoning, which are pathogenic factors and can reduce the patient's resistance.

　　⑤Avoid cold and slippery intestinal foods. Examples include water chestnuts, soft-shelled turtles, unripe pears, peanuts, and other foods that are cold in nature and harm the spleen and stomach, causing diarrhea due to slippery intestines, so they should be avoided.

　　⑥ Avoid spicy and hot刺激性 food, leeks, mutton, chili, fresh chili powder, strong tea, alcohol, and various coffee drinks, as they are strong irritants that cause vasoconstriction, mucosal congestion, edema, and damage, so they should be avoided.

　　Isolation of the digestive tract. Pay attention to adequate rest and easy-to-digest diet.

　　1. Acute dysentery

　　(1) General treatment: Symptomatic treatment should be given when there is high fever, frequent diarrhea, and severe abdominal pain. Oral rehydration solution should be used for dehydration: 20g of glucose, 3.5g of sodium chloride, 2.5g of sodium bicarbonate, or 2.9g of trisodium citrate, 1.5g of potassium chloride, added to warm tap water to 1000ml. Intravenous rehydration should be given if dehydration is significant. Alkaline solution should be given if acidosis occurs.

　　(2) Antimicrobial therapy: Select drugs based on the specific situation of the patient at that time and place. Children should be cautious when using fluoroquinolone drugs.

　　① Norfloxacin, 0.4g per dose, twice daily; 15-20mg/kg/day for children, taken in two doses, 5-7 days as a course.

　　② Enoxacin, 0.4g per dose, twice daily; 15-20mg/kg/day for children, taken in two doses, 5-7 days as a course.

　　③复方新诺明：Each tablet contains 400mg of SMZ and 80mg of TMP, 2 tablets per dose, twice daily, double the first dose, and adjust the dose for children. 5-7 days as a course. Contraindicated for those with sulfonamide allergy, liver and kidney dysfunction. Pay attention to blood count during medication.

　　④ Methotrexate (TMP): Often used in combination with sulfonamide drugs, antibiotics, or traditional Chinese medicine. 0.1-0.15g per dose, twice daily; 5-8mg/kg/day for children, taken in two doses, 5-7 days as a course. Pay attention to blood count during medication.

　　⑤ Antibiotics: Select aminoglycoside antibiotics for intramuscular injection as appropriate, such as gentamicin sulfate 0.2-0.4g, twice daily;庆大霉素 80,000U, twice or three times daily; followed by ampicillin 4-8g/day, intravenous infusion; fosfomycin sodium 2-6g/day, intravenous infusion. Ciprofloxacin 0.2g, twice daily, intravenous infusion can also be used.

　　⑥ Short-term rapid therapy: Norfloxacin 0.6g or berberine 1g (or tetracycline 1.5, plus TMP 0.2g, once every 12 hours, 4 times as a course. Increase prednisone 10-20mg if feverish, and anisodamine (654-2) 10-20mg if abdominal pain.

　　2. Toxic dysentery

　　(1) Relief of vascular spasm: Vasodilator drugs should be administered early in the disease to relieve vascular spasm, such as anisodamine (654-2) or atropine. The dose of 654-2 is 40mg per dose, 1-2mg/kg for children, intravenously every 10-15 minutes. Increase the dose to 50-60mg per dose, 3-4mg/kg for children, if the condition is critical. Discontinue medication when the limbs become warm, the face slightly red, and respiration and circulation improve. Atropine can also be used, 0.03-0.05mg/kg per dose, with the same administration as 654-2.

　　(2) Hypothermia and anticonvulsant therapy: High fever is prone to cause convulsions, which can worsen cerebral hypoxia and edema. Hypothermia should be achieved by physical methods, and at the same time, 1000ml of 1% warm saline enema should be administered, and appropriate antipyretic agents should be used. For patients with extreme restlessness, 10mg of diazepam can be administered intramuscularly or intravenously; or 40-60mg/kg of chloral hydrate can be administered by enema; or 5mg/kg of phenobarbital sodium can be administered intramuscularly.

　　(3) Prevention and treatment of circulatory failure

　　①Expansion of blood volume, correction of acidosis, and maintenance of water and electrolyte balance: For patients without obvious water and electrolyte imbalance, supplementation according to physiological needs is required, with adults receiving 2500-3000ml per day, and children 80-100ml/kg per day, administered in divided doses intravenously. The first 2-3 batches use half-isotonic fluid, followed by one-third isotonic fluid. For patients with severe vomiting and diarrhea, obvious acidosis, and circulatory failure, 5% sodium bicarbonate solution is first used, with adults receiving 250-300ml per dose, and children 5ml/kg, administered intravenously rapidly or by push injection. Then, a 2:1 solution (2 parts normal saline, 1 part 1.4% sodium bicarbonate solution) is used, with adults receiving 500ml per dose, and children 10-20ml/kg, administered intravenously. Subsequently, 6% low-molecular-weight dextran is used, with adults receiving no more than 500ml per dose, and children 10-20ml/kg (not exceeding 300ml in a single dose) administered intravenously. When there is urination, correction of acidosis, and improvement of circulation, switch to physiological maintenance fluid for supplementation. Potassium supplementation is required for hypokalemia. The total volume and speed of fluid administration should be controlled according to the condition.

　　②Application of vasodilator drugs: On the basis of volume expansion and acid-base correction, or simultaneously with them, vasodilator drugs should be administered according to the clinical needs to improve microcirculation. 654-2 is commonly used, with the same administration method as above.

　　③Hormonal therapy: Early application of hormones can quickly alleviate symptoms of high fever and infection intoxication, and prevent the aggravation of the condition. Prednisolone (hydrocortisone) or dexamethasone are commonly used. The dosage of prednisolone for adults is 300-400mg per day, for children 5-10mg/kg per day, administered in 3-4 divided doses, intravenously infused into glucose solution or normal saline. The dose of dexamethasone is 0.5-1.0mg/kg, administered intravenously through a syringe pump in the infusion bottle, and can be repeated every 6 hours if necessary.

　　④Application of digitalis preparations: Patients with cardiac insufficiency can be treated with digoxin or strophanthin K.

　　⑤Application of vasoconstrictor drugs: The early application of vasoconstrictor drugs can aggravate microcirculatory disorders and reduce tissue perfusion, with more disadvantages than advantages. After comprehensive measures such as volume expansion, acid-base correction, application of vasodilator drugs, cardiotonic drugs, and hormone therapy, if there is no significant improvement or even deterioration of shock symptoms, antihypertensive drugs such as metaraminol or dopamine can be added.

　　(4) Prevention and treatment of cerebral edema and respiratory failure.

　　①Application of high-dose atropine treatment (method same as above).

　　②Application of desiccant therapy: When there are signs of cerebral edema, 20% mannitol or 25% sorbitol at a dose of 1.0g/kg should be administered intravenously immediately, once every 4-6 hours, alternating with 50% glucose. If necessary, 30% urea at a dose of 0.5-1.0g/kg can be used for intravenous push injection until the symptoms of cerebral edema disappear.

　　③ Other: Intravenous fluid therapy, oxygen therapy. Suctioning, keeping the respiratory tract unobstructed. If respiratory arrest occurs, intubation or tracheotomy should be performed immediately, and artificial respiration should be used with a respirator.

　　(5) Antimicrobial treatment: In recent years, drug-resistant strains have gradually increased. In order to effectively control infection, the combined use of two antimicrobial drugs should be used. Aminopenicillin and gentamicin can be used for intravenous infusion or intramuscular injection, with the same dosage as before. After the patient can take oral medication or the symptoms of poisoning improve, treatment should be given according to acute bacillary dysentery.

　　(6) Treatment of associated diseases and complications.

　　3. Chronic bacillary dysentery

　　(1) Regular lifestyle, pay attention to strengthening the physique: The lifestyle of chronic bacillary dysentery patients should be regular, and except for acute attack type, they can appropriately participate in some light physical activities such as physical exercises, Tai Chi, and qigong, which can help to enhance the physique and recover physical strength. For patients with poor appetite, long-term diarrhea, and poor digestion and absorption, attention should be paid to the supplementation of vitamins B and C.

　　(2) Rational use of antimicrobial drugs: For patients with positive fecal bacterial culture, drug sensitivity test should be performed and sensitive drugs should be selected for treatment. For patients with negative fecal culture, antimicrobial drugs that have not been used before should be used, or more effective drugs should be used according to the situation of drug-resistant strains in the region. It is best to use two antimicrobial drugs for treatment, and the course of treatment should be extended to 10 to 14 days. Sometimes multiple courses can be repeated until symptoms disappear and bacterial examination turns negative. However, it is forbidden to use antimicrobial drugs excessively, otherwise it is easy to cause an increase in drug-resistant strains and dysbiosis of intestinal flora.

　　(3) Treatment of intestinal mucosal lesions: For patients with intestinal mucosal lesions, 2% sulfadiazine silver gel suspension or 0.3% coptis liquid can be used for retention enema treatment. The dosage is 200ml each time, and retention enema is given once a night for 14 to 21 days as one course of treatment.

　　(4) Treatment of intestinal dysfunction: Patients who have been taking antibiotics for a long time are prone to intestinal dysfunction, manifested by an increase in defecation frequency, but no obvious abnormalities are found in the microscopic examination of fecal smears. Lactobacillus acidophilus, lactobacillus casei, or bifidobacterium preparations can be used for treatment.

　　(5) Other treatments: For patients with abnormal immune function, appropriate immune modulators should be used. For complications or concomitant diseases such as intestinal parasites (ascaris, hookworm), anemia, or other diseases, appropriate treatment should be given.