pseudomembranous colitis
Introduction
Introduction to pseudomembranous colitis Pseudomembranous colitis (PMC) is also known as refractory fusiform anaerobic enteritis, post-operative enteritis, antibiotic enteritis, antibiotic-induced difficile anaerobic bacillary enteritis, etc. PMC often occurs after major surgery and In patients with critical and chronic wasting diseases, the use of broad-spectrum antibiotics, especially after oral administration of chlortetracycline, promotes the dysregulation of the intestinal flora, the abnormal reproduction of Clostridium oxysporum, and the production of oxytocin Shock inflammation, which forms a pseudomembrane on the necrotic mucosa. basic knowledge The proportion of sickness: 0.0026% Susceptible people: no specific population Mode of infection: non-infectious Complications: shock dehydration peritonitis intestinal obstruction toxic shock syndrome
Cause
Cause of pseudomembranous colitis
(1) Causes of the disease
Pseudomembranous colitis is caused by the production of toxins by two floras.
1. Clostridium difficile is an important cause of pseudomembranous colitis associated with antibiotics. In 1935, elongated and strict anaerobic Gram-positive was first isolated from infant feces by Hall et al. Bacillus, which is a resident bacteria in the intestines of normal people. In patients who are not treated with antibiotics, the number of Clostridium difficiles accounts for only 2% to 3% of anaerobic bacteria. The toxins are few, and even do not produce toxins that cause disease to humans. The detection rate of Clostridium difficile in the population is 5% to 13%. Under normal circumstances, these bacteria are mutually restricted, cannot be multiplied, and will not cause disease. Long-term use of a large number of antibiotics can inhibit the growth of various bacteria in the intestine, and the drug-resistant Clostridium difficile, which is not affected by antibiotics, rapidly multiplies, and the Clostridium difficile in stool can be as high as 10% of anaerobic bacteria. ~20%, a large amount of exotoxin is produced, causing mucosal necrosis, exudative inflammation with pseudomembrane formation, and this exotoxin can be found almost in all stools of pseudomembranous colitis.
Clostridium difficile produces at least four substances, toxin A (enteric toxin), toxin B (cytotoxin), motility-influencing factor and a heat-sensitive toxin, wherein toxins A and B have been purified.
Toxin A has a molecular weight of 500,000 and toxin B has a molecular weight of 360,000. They are all composed of glycoproteins, sensitive to acids and bases, and resistant to ethers. The two toxins are mostly destroyed at 50 ° C for 30 min. Trypsin, chymotrypsin and cell protease are sensitive and are not decomposed by ribonuclease and DNase. At pH 4 or pH 10, the toxicity of toxin B disappears and the virulence of toxin A is not affected.
Toxin A can stimulate mucosal epithelial cells to increase the secretion of water and electrolytes, causing a large loss of water and electrolytes. Toxin B can cause local allergic reactions to degeneration and necrosis of intestinal mucosa, and cellulose and mucin exudate to form pseudomembranes. Oral injection into animals can cause enteritis and death. Toxin A can stimulate intestinal mucosal epithelial cells to activate guanosine cyclase at low concentrations, resulting in an increase in intracellular G-phosphate guanosine. The role of toxin A and toxin B is Synergistic, first toxin A causes intestinal tissue lesions, after which toxin B acts on these damaged tissue cells. Both toxins are antigenic and can interact with the corresponding antibodies. Toxin A antiserum cannot neutralize toxin B. While the anti-blood clearance of toxin B neutralizes toxin B, it can also neutralize part of toxin A. In addition, toxin B can be neutralized by Clostridium solani anti-toxin.
The third toxin motility factor is present in the filter sterilizing supernatant of Clostridium difficile culture medium, which can change the electrical activity of rabbit ileum iliac muscle. The fourth toxin is low molecular weight protein, which is sensitive to heat. It is very unstable, and its action is the same as that of Vibrio cholerae and Escherichia coli, which can cause an increase in the secretion of ileal fluid in rabbits, but does not cause tissue damage.
2. Coagulase-positive hemolytic drug-resistant Staphylococcus aureus inhibits the intestinal tract including Escherichia coli after using a large number of broad-spectrum antibiotics (such as oxytetracycline, chloramphenicol, tetracycline, ampicillin, cephalosporin, etc.) The various flora, resistant Staphylococcus aureus, multiply and produce exotoxin, leading to the occurrence of pseudomembranous colitis. Gram staining of the stool smears of such patients can find piles of cocci, such as this The bacteria produced by the toxins can also be injected into the animals. Pseudomembranous colitis can also occur. It has been reported that 17% of Staphylococcus aureus is detected in the stool of a group of admitted patients, and golden yellow grapes are found in the stool after 1 week of antibiotic treatment. The detection rate of cocci is 38% to 40%.
It is also believed that in pseudomembranous colitis, Staphylococcus aureus is only a concomitant bacterium is not a true pathogenic factor, and some people have not found golden yellow in tissue culture or stool culture of autopsy material of pseudomembranous colitis. Staphylococcus, it has also been reported that antibiotic-associated pseudomembranous colitis patients have Staphylococcus aureus and its toxins in the stool, but the aforementioned Clostridium difficile and toxin are not seen, which shows that it has been proved difficult at present. Clostridium difficile is an important cause of antibiotic-associated pseudomembranous colitis, but not all pseudomembranous colitis is caused by Clostridium difficile.
Under normal circumstances, the gastrointestinal tract is a balanced ecosystem. There are a large number of bacteria in the intestine. The bacteria and the number of these bacteria are basically constant. These bacteria help the bacteria itself and the antibodies it produces. Infection, once certain factors cause the system to lose its ecological balance, it will cause disease, and the proportion of antibiotics most likely to produce flora is imbalanced. Therefore, it is one of the important causes of pseudomembranous colitis, and the antibiotics most commonly cause pseudomembranous colitis. In turn, ampicillin, clindamycin and cephalosporins, not often caused by penicillin, erythromycin and sulfamethoxazole, can even cause chloramphenicol, tetracycline, metronidazole and aminoglycosides Drugs, cancer and surgery are important susceptibility factors.
(two) pathogenesis
Pathogenesis
The bacteria in the intestines come from the mouth, and the bacteria that enter the digestive tract from the outside are mostly killed by stomach acid when passing through the stomach. Only a small number of unkilled bacteria enter the duodenum and the upper part of the ileum, duodenum and The surviving bacteria in the jejunum are mainly Gram-positive streptococci, Lactobacillus, Mycobacterium and yeast, with a total number of less than 105/ml. The number of bacteria in the lower and middle ileum begins to increase, and the content is estimated to be 105-106/ml in the ileum. The last part is mainly aerobic Escherichia. After the intestinal contents enter the large intestine, the bacteria are neutral or weakly alkaline in the anoxic environment, and the contents are moved in a slow and vigorous condition. The main one is Anaerobic opportunistic flora, the number of anaerobic bacteria can be as high as 1011 per ml of colon content, and the normal human intestinal tract is mainly obligate anaerobic bacteria, and facultative aerobic bacteria only account for 1%.
The normal flora in the digestive tract is regularly distributed according to the colonization of bacteria, excreted and excreted while living, and remains unchanged for life. The results of the study on the fecal flora of healthy people in China are similar to those reported in foreign countries, suggesting that the intestinal flora is Anaerobic bacteria mainly, the average order of 9 common bacteria are: Bacteroides, Bifidobacterium, True bacillus, Enterobacter, Lactobacillus, Enterococcus, Clostridium, Staphylococcus, Yeast, bacteria in normal human intestinal tract The division cycle is 6 to 48 hours. In addition to the important role of gastric acid in maintaining the number of bacteria in the jejunum, the gastric and jejunal mucosa also have an intrinsic pH-independent inhibition characteristic. In the stomach and small intestine of patients with gastric acid deficiency or partial gastrectomy, A significant increase in the number of aerobic and anaerobic bacteria was observed, and Escherichia coli and anaerobic Gram-negative bacilli were present in the proximal small intestine, and the number of streptococcus, lactobacilli and fungi also increased.
The normal flora promotes the digestion and absorption of nutrients in the body and participates in the absorption and metabolism of cholesterol, steroids, fats, proteins, lipids, amino acids and certain drugs in the body.
The intestinal flora plays a non-specific immune role through the following mechanisms: 1H2O2 action; 2 bacterial toxin action; 3 space-occupying protection; 4 organic acid action; 5 competition for nutrition, normal flora can also produce multiple antigenic substances Stimulates the body's immune response, keeps the immune system active and protects against multiple infections. The intestinal flora is disordered. If the amount of bacteria is reduced, it will cause lymphatic tissue dysplasia, lymphocyte proliferation, bloody cell loss, gamma globulin content, etc. The weakening of lymphokine secretion will also affect the cellular immune response, the establishment of delayed type allergic reaction. One of the main physiological functions of Escherichia coli is its immunogenicity. Escherichia coli can produce trace amounts of toxins like other normal flora. An immunogen causes an immune effect on toxins.
The composition of the intestinal flora is affected by physiological factors such as intestinal peristalsis, digestive tract pH, intestinal endocrine enzymes, mucus, antibody secretion and function, and changes with intestinal bacterial interactions, food, drugs, climate, and age. .
Normal bowel movement is the main defense mechanism to prevent bacteria from overgrowing in the small intestine. The small intestine relies on strong creep to make the bacteria in the intestine cavity far less than the colon. When the intestinal peristalsis is reduced, the small intestine bacteria will grow densely, and the stomach acid will kill the upper small intestine. Bacteria make the flora of this part rare, once the stomach acid is reduced, the amount of aerobic and anaerobic bacteria entering the stomach and small intestine will increase significantly, and E. coli and anaerobic Gram-positive bacteria appear in the proximal small intestine, while fungi and The number of streptococcus has also increased accordingly.
Under normal circumstances, the bacteria in the human intestine are interdependent and mutually restrict to form a natural ecological balance between bacteria and human body. The bacteria present in the intestine are basically balanced in the species and quantity, and the content per gram in the large intestine The number of bacteria in the body is 1010~1011, and the small intestine also contains 108. Under normal ecological balance, these bacteria resist the pathogenic bacteria by the bacteria and the bacteria to produce the antibodies produced by the human body. The bacteria do not constitute humans. Harmful and can also synthesize certain vitamins, a large number of antibiotics, especially oral administration to change the balance between intestinal bacteria, dysbacteriosis of intestinal bacteria, non-pathogenic intestinal bacteria, such as the large intestine Bacillus and other bacteria are killed by antibiotics, and bacteria with relatively strong resistance, such as Staphylococcus aureus, Pseudomonas aeruginosa, some Bacillus capsulatus and fungi, rapidly grow and secrete, secrete exotoxin to cause intestinal lesions. The immune function and disease resistance of the patient's body decline or some diseases lead to intestinal ischemia, congestion, etc. can lead to intestinal flora imbalance Health pseudomembranous colitis.
The occurrence of pseudomembranous colitis requires a disorder of the intestinal flora, endogenous or exogenous refractory Clostridium or Staphylococcus aureus, and the above-mentioned bacteria produce toxins and susceptible organisms.
In infants and young children, Clostridium difficile is one of the normal intestinal flora. Because the toxin receptors on the intestinal mucosa of newborns and infants may not be mature, it will not cause disease. It is difficult for infants in less than one month. Clostridium difficile can account for more than 50% of the total bacteria, 30% to 90% of infants within 1 year of age carry the bacteria in the intestines, and then gradually decrease with age, accounting for the intestinal tract in adulthood 3% of bacteria.
After the patient uses antibiotics, the intestinal flora is killed or inhibited, resulting in disorder of the normal flora. Although the Clostridium difficile is also largely eliminated, it is easy to multiply if the antagonistic bacteria are reduced. The patient was not carriers before receiving antibiotics. After receiving antibiotics, the aerobic and anaerobic bacteria in the intestines were removed, and the intestinal colonization resistance decreased, resulting in the bacterial receptors on the intestinal mucosal cells originally occupied by these bacteria. Clostridium difficile from the outside adhered to settle.
In addition to the use of antibiotics, other diseases not treated with antibiotics, such as partial gastrectomy or vagus nerve ablation plus pyoplasty, gastrectomy, gastrojejunostomy, duodenum or jejunum diverticulum, surgical blindness (end side anastomosis), intestinal obstruction (stenosis, adhesion, inflammation, cancer) intestinal short circuit and sputum effect, low gastric acid and accompanied by motor dysfunction, intestinal fistula, ileocecal resection, etc. can cause gastrointestinal Changes in motor function, combined with changes in the environment of the intestine, such as ileocecal resection, loss of ileocecal valve plays an important role in regulating the normal distribution of intestinal flora, can not prevent the colonic flora from flowing back into the small intestine, weakening the intestinal tract Others such as leukemia, malignant tumors or receiving radiotherapy, chemotherapy, hormone therapy and infection, chronic wasting diseases can also change the ecological balance of the normal intestinal flora, and the feces may be separated. Clostridium difficile-producing strains, pseudomembranous colitis.
2. Pathology
Histological studies have shown that typical pseudomembranous colitis has histologically specific lamellar pathological changes, no vasculitis, early lesions, normal mucosa between lesions and lesions, advanced mucosa completely necrotic and only a small number of glands The body survives, covered with a thick layer of inflammatory cells, mucin and cellulose, edema and inflammation continue to develop, extending to the submucosa or even beyond the submucosa is not easy to distinguish from other intestinal inflammation.
About 60% of the lesions occur in the small intestine, 15% occur in the large intestine, and 25% in the large intestine. The pathological changes are mainly confined to the mucosa and submucosa. The affected intestines may have staged distribution of mucosal necrosis, pseudomembrane formation, and mucosal lesions. It is characterized by congestion and edema, and localized necrotic lesions can fuse with each other.
(1) Gross morphology: The intestinal lumen of pseudomembranous colitis is visible to the naked eye, and a large amount of thick mucus accumulates. The mucosa is covered with spots or patches of yellowish white, yellow, brown or yellow scattered from several millimeters to several centimeters. The green pseudomembrane is severely fused into a piece to completely cover the entire intestine segment with a pseudomembrane. The pseudomembrane is formed by the solidification of cellulose, neutrophils, monocytes, mucin, bacteria and necrotic cells, and the pseudomembranous texture is soft. It is brittle, easy to separate from the mucous membrane, floats in the intestinal fluid and excretes with the stool. After the pseudomembrane falls off, the submucosa is exposed to form an ulcer, the serosa is congested, edematous, thickened, even necrotic and perforated.
(2) Histomorphology: under the microscope, the mucosa of the lesion is congested, and the mucous gland tube contains a lot of thick mucus. After the mucus is discharged, it participates in the composition of the pseudomembrane. When the lesion is heavy, the villi and the top of the mucosa have different degrees of necrosis or disappearance. In the lamina propria, there are neutrophils, plasma cells and lymphocytes infiltration, glandular rupture and necrosis, submucosal telangiectasia, congestion and thrombosis, and vascular wall necrosis can lead to mucosal ischemic necrosis. The lesions are generally limited to the mucosal layer. However, it can also extend to the submucosal layer to involve the whole layer, and even lead to large pieces of necrosis. Generally, it can be divided into mild, severe and severe type 3 according to the degree of disease:
1 mild lesions: the initial lesion is the appearance of acute inflammatory cells in the lamina propria of the mucosa, eosinophil infiltration and cellulose exudation, formation of focal necrosis, fibrinogen and polymorphonuclear in necrotic lesions Cell aggregation forms a special apical lesion.
2 severe lesions: the lesion did not invade the submucosa, the mucosal glands were destroyed, the pseudomembrane formed, the destruction of acute inflammatory cells containing mucin and the gland was covered by a typical pseudomembrane, the lamina propria neutral polymorphonuclear cells Infiltration, accompanied by typical volcanic ridge-like necrotic lesions.
3 severe lesions: the mucosa is completely destroyed, the deep layer of the lamina propria is violated, and the lamina propria is covered by a thick and intertwined pseudomembrane.
Prevention
Pseudomembranous colitis prevention
(1) Strictly grasp the indications for the use of antibiotics to prevent abuse, and the preventive application of antibiotics should be strictly controlled.
(2) Chloramphenicol is a drug with anti-S. aureus and anaerobic fragile bacilli, but when the above bacteria are infected, unless other drugs are ineffective or have no conditions, it is generally not suitable to use clindamycin and linco Ampicillin, ampicillin is also easy to wear pseudomembranous colitis, should be noted in clinical use.
(3) Clinicians should seriously observe the complications of using antibiotics, identify and confirm them early, so as not to delay the treatment. Patients with diarrhea should be stopped in time for fecal examination. If necessary, repeat sigmoidoscopy, especially for clinical suspected pseudomembranous There are unexplained fever patients in patients with colitis or after major bowel surgery.
(d) Bartlet believes that patients who are going to be treated with clindamycin or lincomycin may be given oral vancomycin to prevent the occurrence of pseudomembranous colitis.
Most patients can recover from illness after treatment. Some patients can be self-healing. Some patients can get better after treatment, but diarrhea can occur again. In severe cases, especially after elderly patients with intestinal surgery, the mortality rate can reach 50%. ~70%, in recent years due to timely diagnosis and treatment, the mortality rate has dropped below 30%.
The prognosis of this disease is often quite serious. The clinical work should prevent the occurrence of this disease as much as possible. First of all, attention should be paid to the use of antibiotics to avoid the abuse of antibiotics to reduce the incidence of pseudomembranous colitis. In particular, the use of broad-spectrum antibiotics should have a clear purpose. In order to achieve the desired effect, the drug should be discontinued in time. For elderly patients with frail surgery, especially after major abdominal and pelvic surgery, and cancer patients with low immune function should avoid using antibiotics that are easy to induce Clostridium difficile. For patients who must use antibiotics, they should be vigilant, early detection, timely treatment, and reduce the occurrence of severe pseudomembranous colitis.
It is necessary to frequently introduce the onset of pseudomembranous colitis to the medical staff to prevent the growth of drug-resistant strains. The exogenous C. difficile may be a cross-infection in the hospital, some people from the hospital floor, bathroom utensils, As well as the detection of Clostridium difficile or its spores in the hands and stools of staff members of patients with pseudomembranous colitis, it is necessary to take necessary isolation measures and environmental disinfection for cases of pseudomembranous colitis to prevent passage through the room and skin. Medical devices cause cross-infection of the refractory Clostridium.
Complication
Complications of pseudomembranous colitis Complications, shock dehydration, peritonitis, intestinal obstruction, toxic shock syndrome
Severe cases can be complicated by irreversible shock, rapid dehydration, acidosis; or complicated acute abdomen with toxic megacolon, colon perforation or peritonitis, can also be complicated by acute intestinal obstruction; can be complicated by hypoproteinemia, multiple arthritis, etc. Causes toxic shock, toxic megacolon, intestinal paralysis, hemorrhagic necrosis of the intestinal wall and even intestinal perforation.
Symptom
Pseudomembranous inflammatory symptoms common symptoms peritonitis abdominal pain mixed acid-base balance disorder tachycardia gastrointestinal toxic megacolon shock diarrhea intestinal perforation bloating
The disease usually occurs in tumors, chronic wasting diseases and the application of antibiotics after major surgery. Most of the onset is rapid and the disease develops rapidly. The earliest time of onset can be several hours after the start of medication, but it can also be after withdrawal. About 3 weeks, about 20% of patients started on 2 to 10 days after stopping antibiotics.
1. Fever 10% to 20% of patients with fever, white blood cells rise, individual can present leukemia-like blood-like images, mild patients with moderate fever, severe patients can have high fever.
2. Diarrhea is a prominent symptom of this disease. Muscle inflammation and exotoxin stimulation damage the absorption function of the diseased intestine, affecting the intestinal absorption of intestinal contents, causing the intestinal wall to secrete water and sodium in the intestinal lumen, and the liquid infiltrates into the intestine. The cavity causes a large amount of intestinal fluid to cause diarrhea. The degree of diarrhea depends on the number of bacteria, the size of the virulence and the resistance of the patient. The lighter is used several times a day or more than ten times, and the original antibiotic is stopped. Targeted drugs can be cured; severe cases of severe diarrhea, discharge of sputum smelly purulent mucus blood, up to 20 to 30 times a day, daily defecation volume up to 4000ml, or even as much as 10000ml, in the feces Blood or plaque-like pseudomembrane has appeared. It has been reported that a severely ill patient has a pseudo-membrane type of 60 cm long. Infected with Staphylococcus aureus is often a green watery stool, and Clostridium difficile can be a yellow egg pattern. Water, such as the occurrence of toxic intestinal paralysis can not rule out a large amount of liquid accumulated in the intestine, the number of diarrhea is reduced, but the condition becomes more serious.
3. Abdominal pain , abdominal distension in the inflammation and intestinal toxin stimulation, the intestinal tube is sparsely contracted to cause varying degrees of abdominal pain, severe cases can be very severe with early bowel sounds hyperthyroidism, intestinal peristalsis dysfunction, can not effectively empty Accumulation of fluids and gases in the intestines causes bloating. Pseudomembranous colitis occurs during frequent diarrhea and is different from general diarrhea. In severe cases, there may be typical symptoms of toxic megacolon. In severe cases, abdominal pain, bloating, and intestines Type, total abdominal muscle resistance and tenderness, bowel sounds weakened or disappeared, intestinal necrosis, diffuse peritonitis appeared in perforators, obvious resistance to whole abdominal muscles, tenderness and rebound pain, bloating was more obvious, and symptoms of systemic poisoning were more serious As a result, they are caught in toxic shock, and some patients have ascites.
4. Toxemia and shock are the late manifestations of severely ill patients. After a large amount of toxin absorption, there is a significant loss of appetite, high fever, tachycardia, listlessness, paralysis, poor orientation, disturbance of consciousness, deep breathing, cold hands and feet, blood pressure. Unstable, etc., eventually lead to irreversible shock of liver and kidney dysfunction, individual patients with acute onset, mainly manifested as high fever, severe abdominal distension, hematemesis, blood in the stool, shock within a few hours, and death.
Chinese medicine divides the present into four types:
1, mildew heat flaming type: because of damp heat is heavier, treatment is unsuitable, damp heat and poison, so that the wet mold heat and evil knots, stagnation in the coke, clear and turbid, no diarrhea, mildew into the blood, Zheng Jian High fever, polydipsia, blood stasis, short urine, red blood pour, sputum color or egg pattern loose stools, even heat closed inside, consumption of semen, cold limbs, dizzy, red tongue, pulse Number of strings or fine numbers.
2, heat Sheng Yin consumption type: due to the patient's body yin deficiency, or postpartum, postoperative blood and blood two injuries, wet mold heat evil for a long time, yin blood consumption, and because of the diarrhea after the death, resulting in Yin The body is declining, the image of toxic heat is on the day, it is imaginary and evil, the condition is critical, the disease is high fever, the sun is hot, the mouth is dry or not wanting to drink, blush, five upset hot, short urine , it will be thin and diarrhea, red tongue, pulse number.
3, spleen deficiency wet type: factors spleen deficiency, wet turbid spleen, transport dereliction of duty, water tends to the large intestine, can not separate water valley, into diarrhea, then humidification soaking, treatment is not appropriate, not only damage the stomach yin, but also damage the spleen Yang, so that the spleen is wet and spleen, clear and turbid, and the symptoms are pale, the gods are tired, the food is less, the food is less, the thirst does not want to drink, or the chills, cold, edema, diarrhea, frequent stools, tongue coating White, the pulse is fine.
4, spleen and kidney deficiency, yang deficiency and desire type: due to pouring irradiance, must be more yin, Yin yang is not attached, causing yin yang detachment, symptoms see body weight loss, limbs cold, chills tired, abdominal distension abdominal pain , diarrhea straight down, anal valgus, and even the tongue is shrinking, the pulse is minimal.
Major surgery, long-term use of large amounts of antibiotics, severe chronic diseases or high-risk patients suddenly have fever during the recovery process, diarrhea, discharge of green seawater or egg-like water should first think of this disease, malignant tumor during chemotherapy and gastrointestinal malignancy The incidence of tumor after the major surgery is higher, such as the stool smear for Gram staining to find a large number of positive cocci, while the reduction of negative bacilli can be basically diagnosed, atypical cases due to the lack of typical performance of stool, often cause diagnosis Difficulties, patients with diarrhea due to surgery or antibiotics should repeat the stool smear examination, observe the changes in the proportion of cocci and bacilli, if necessary, colon endoscopy, if necessary, with the antibiotic toxins of Clostridium difficile The method for determining the presence or absence of dysfunctional Clostridium toxin in stool can help diagnose.
Examine
Examination of pseudomembranous colitis
Blood biochemical examination:
Electrolyte disorders can be seen, often with low potassium, low sodium and hypoproteinemia, serum albumin is less than 3%, white blood cell count can be as high as 20 × 109 / L, and mainly neutral cells.
Anoscope, sigmoidoscopy: visible mucosal congestion, edema, erosion, ulceration, patch of multiple bulging sigmoid colon or fusion of large grayish green brown pseudomembrane covering the mucosal surface, is the main sign of the disease, severely each other Mixed, pseudomembrane adjacent to the mucosa can be edema, congestion, easy to hemorrhage, can also be seen scattered ulcers, pseudomembranous lesions mainly involving the left colon or the whole colon, a few involving the ileocecal.
X-ray inspection:
Abdominal X-ray plain film has no special findings, can show intestinal paralysis or intestinal flexion, visible liquid level, due to colonic edema, can appear thumb-like imprint, occasionally spontaneous megacolon, tincture X-ray, in early or light patients No special changes, late and severe cases, visible colonic peristalsis, mucosal thickening, intestinal sputum, distortion, mucosal ulcers, etc., barium enema can often make the condition worse, it is generally not recommended.
Fecal routine
Microscopic examination of fecal smears, if Gram-positive bacilli and their spores are found to be helpful for clinical judgment, can be followed by staged bacterial culture to check for the presence of a large number of Gram-positive bacteria.
Bacteriological examination
In 90% of cases, C. difficile can be cultured in the feces at the time of onset. In order to reduce contact with air, it is necessary to take fresh feces at least more than the container capacity, and the container is placed in a wide-mouth sealed mouth. In the bottle, the test was sent within 20 minutes, and the CCFA-specific medium (composed of cycloserine, thiophene methoxycephalosporin, fructose and protein agar) was inoculated to selectively isolate the difficile spores under anaerobic conditions. Bacillus, if the colony is flat, the edges are irregular, rough, and Gram staining is a positive bacillus to make a diagnosis.
Toxic toxicity test
The diluted stool or bacterial culture filtrate has a specific cytopathic effect on tissue culture cells (HELA), and this effect can be neutralized by the antitoxin of Clostridium septicum, thereby confirming that Bacillus licheniformis is a toxigenic strain.
Toxin A detection
Toxin A can be examined by convection immunoelectrophoresis, enzyme-linked immunosorbent assay, latex agglutination assay, monoclonal antibody method, and the like.
Colonoscopy
Pseudomembranous colitis invades the colon at the same time, especially the sigmoid colon can be examined by colonoscopy. It has been reported in the country that 16 patients with pseudomembranous colitis have been examined by fiberoptic colonoscopy, and 14 of them have found lesions in the rectum and sigmoid colon. It is characterized by mucosal redness and edema with plaque or fused pseudomembrane. Biopsy shows acute inflammation of the mucosa. The pseudomembrane contains necrotic epithelium, fibrin, inflammatory bacteria, etc. It is necessary to master the progression of the disease when using colonoscopy. In the stage, enteritis has not formed a pseudomembrane or the local pseudomembrane has fallen off. The pseudomembrane may not be found under the microscope. Therefore, the pseudomembrane is not necessarily the only diagnosis. The absence of the pseudomembrane does not necessarily rule out the disease. Enteritis lesions can be skipped. In order to prevent missing small lesions, the scope of microscopic examination must include the whole colon. The lesion tissue should be taken at a representative site, and the biopsy should have a certain depth.
Ultrasound diagnosis
Ultrasound can detect the local intestinal wall pseudomembrane, mucosal and submucosal edema caused by severe thickening, narrowing or disappearing of the intestinal lumen, careful exploration of the pseudo-renal sign of intestinal tuberculosis or tumor in the right lower abdomen, good conditional ultrasound diagnostic apparatus In addition, the level of lesions can be more accurately distinguished. In addition, ultrasound diagnosis can detect ascites accompanied by disease.
CT diagnosis
The performance of CT is not specific, and even a thickened intestinal wall with low attenuation can be found.
Diagnosis
Diagnosis and diagnosis of pseudomembranous colitis
diagnosis
1 There is a history of certain antibiotics before diarrhea;
2 typical clinical manifestations such as diarrhea, bloating, fever, increased white blood cell count, severe blood in the stool, toxic intestinal paralysis, intestinal perforation, toxic shock;
3 fecal bacteriological separation, identification of Clostridium difficile;
4 The fecal filtrate or the filtrate of the isolated strain culture has toxin, has a cytopathological effect in tissue culture, and can be neutralized by Clostridium difficile antitoxin or Bacillus subtilis antitoxin.
Differential diagnosis
1. Intestinal torsion or intussusception after intestinal torsion or intussusception caused intestinal ischemia, hypoxia, after the improvement of blood circulation, due to the absorption of toxins, high fever and diarrhea, sometimes need to identify with pseudomembranous colitis, intestinal torsion or bowel The diarrhea that occurs after the telescopic reduction comes from the contents accumulated in the intestine. The number and amount of diarrhea is less than that of pseudomembranous colitis and it is not more and more. The content contains more formation than pseudomembrane. Enteritis, although there may be transient symptoms of systemic poisoning, the general trend is gradually relieved, there is no typical water sample in the stool, and there is no possibility of a pseudomembrane. The bacterial smear or culture is not dominated by cocci, and it is not difficult to distinguish. Clostridium difficile.
2. Ulcerative colitis Ulcerative colitis often has a history of long-term diarrhea. In severe cases, there may be more than ten watery stools per day. A few acute onsets have a rapid onset of symptoms, and may have severe toxic symptoms. A wide range of colonic lesions may be used. Toxic megacolon performance, until intestinal perforation and diffuse peritonitis, ulcerative colitis lesions mainly colon, rectum, lack of pseudomembranous colitis caused by the cause of recurrent episodes, fecal examination without pseudomembrane And related pathogens, mucosa seen as multiple ulcers and polyps, X-ray examination and colonoscopy help to make a diagnosis.
3. Crohn's disease (clonal disease) is more common in 20 to 40 years old, the incidence rate of men and women is roughly equal, acute cases have ileal congestion and edema, mesenteric thickening of lymph nodes, fever, abdominal pain, lumps and perforations, Crowe The course of the disease is longer, the symptoms are mild and severe, and the diarrhea is not serious. The stool is often not formed with loose stools and no pseudomembrane formation. It has nothing to do with antibiotics. The final diagnosis requires barium meal and barium enema. Colonoscopy And tissue biopsy.
Hemorrhagic necrotic enteritis hemorrhagic necrotic enteritis and intestinal mucosal ischemic injury, bacterial infection, more common in infants and children, males are higher than female, lesions mainly in the small intestine, intestinal mucosal stage congestion, edema, hemorrhage , necrosis, may be associated with inflammation of the mesentery and associated lymph nodes, may have acute abdominal cramps, diarrhea, blood in the stool and toxemia, feces have a special stench smell, systemic failure within 1 to 2 days of onset, chills, fever, white blood cell rise and The left side of the nucleus, the appearance of toxic granules and other toxemia, mild hemorrhagic necrotic enteritis only diarrhea and only a small amount of bloody watery stools are not easy to identify with pseudomembranous colitis.
