amebic colitis
Introduction
Introduction to amoebic colitis Amoebic dysentery is an infectious disease whose pathogen is dysentery amoeba (also known as Amoebahistolytica), which is the only pathogenic amoeba in the human body. It belongs to the protozoan gate, the meat foot, and the root foot. Outline. The body consists of only one cell, without a fixed shape, and can be arbitrarily changed. At the same time, it can also extend the pseudo-foot throughout the body, the main function is exercise and feeding. There are three forms of large trophozoites, small trophozoites and cysts in human tissues and feces. When the body's resistance is reduced, the amoeba in the dysentery is in the intestines, destroying the intestinal wall, or invading other organs. The trophozoite is weak in resistance in vitro and is prone to death. basic knowledge The proportion of illness: 0.052% Susceptible people: no specific people Mode of infection: fecal spread Complications: anemia, peritonitis
Cause
Cause of amebic colitis
(1) Causes of the disease:
In recent years, it has been reported that some of the amoeba in the lysate are not pathogenic and can survive in the long-term intestines of some people without causing symptoms. The pathogenic strains are different from the pathogenic strains. The surface antigen component, and does not produce proteolytic enzymes, does not produce corresponding antibodies in the host blood.
(2) Pathogenesis:
The amoeba of the lytic tissue has two different forms of trophozoites and cysts in its life history. After being ingested by the human body, the cysts can pass through the upper part of the stomach and small intestine without loss, and trypsinize the lower part of the small intestine. The mature capsule of the nucleus can be decapsulated into a small trophozoite (diameter 7-20 m), parasitic in the intestinal lumen, taking bacteria as food, not damaging the intestinal wall tissue, and both are splitting and breeding, in the absence of oxygen. The blind part grows well.
When the body's resistance is insufficient or the local intestinal mucosa is damaged, the small trophozoites can become large trophozoites (20-40 m in diameter), which can secrete lysozyme to destroy intestinal wall tissue, invade intestinal mucosa and submucosa, and multiply and form. Localized submucosal abscess, mainly necrotizing substance, rupture of abscess, formation of flask-like ulcer, mucosa between ulcer and ulcer is basically normal, which is obviously different from bacterial dysentery.
When the body's resistance is enhanced, the large trophozoites can become small trophozoites, and can be further changed into capsules (about 10m in diameter), excreted with feces, and can survive for 2 to 4 weeks in a cool and humid environment. Can live for 6 to 7 weeks, but not heat-resistant, 50 ° C 5 min that died, only 4 nuclear mature cysts, only contagious, 1 to 2 nuclear immature cysts are not contagious, but in the right In the external environment, it can develop into 4 nucleus capsules, and large and small trophozoites, such as excreted from the body, die quickly. If the course of disease is prolonged, the destruction of intestinal wall tissue and connective tissue hyperplasia occur simultaneously, which can cause intestinal wall hypertrophy and intestine. The cavity is narrow, and occasionally the "ameaboma" can be formed due to excessive proliferation of connective tissue.
Prevention
Amoebic colitis prevention
Drinking water must be boiled, do not eat lettuce, prevent the diet from being polluted, prevent flies from breeding and killing flies, and inspect and treat those who are in the catering industry and those who are chronic.
Complication
Amoebic colitis complications Complications, anemia, peritonitis
Chronic patients may have anemia and malnutrition, and the intestinal wall tissue is subject to different damages in the acute and chronic phase, which may cause the following complications.
1. Intestinal perforation caused peritonitis: Zeng's report of 254 cases of amoebic sputum, surgery and autopsy proved that there were 19 cases of intestinal perforation, 7.48%, Adams reported that 30 of 3013 cases had peritonitis (3.2%), occurred Although the rate is not high, the prognosis is poor.
2. Amoebic appendicitis: Clark reported that 40% of the 186 cases of amoebic patients had appendicitis, and Criag reported that 26.67% of 60 cases had appendicitis, the incidence was indeed high, so it was high in amebiasis. In the area, many acute abdomen are caused by amebic appendicitis or permeation of the amoebic appendix.
3. Intestinal stenosis: patients with chronic amebic colitis, intestinal wall tissue hyperplasia, hypertrophy and amoebic granuloma formation, leading to stenosis, a small number of patients even form intestinal obstruction and need surgery.
4. Amoebic tumors: Of the 3013 patients reported by Adams, 15 had amoebic tumors (0.5%).
5. Non-specific ulcerative colitis: The amoeba has been completely eliminated and converted into non-specific ulcerative colitis. In Adams' statistics, there were 21 cases (0.7%).
In addition, intestinal bleeding, intestinal polyps and intussusception are rare.
Symptom
Amoebic colonic symptoms common symptoms mucus sticky mucus abdominal pain diarrhea thin stool pus for chocolate color...
The incubation period of amebic colitis varies from 1 to 2 weeks or more, and may have different clinical manifestations due to the number of cysts ingested, the virulence and the resistance of the body.
1. Asymptomatic type: mainly refers to those who are carriers of amoeba. Many people have been neglected because of the mild symptoms, and the Maanshan City Epidemic Prevention Station has reported 22.7 cases of 1166 cases of amoeba positive. % is asymptomatic, and these patients are important sources of infection for this disease.
2. Amoebic enteritis: Similar to common enteritis, patients may have abdominal pain and diarrhea, feces are not formed or loose stools, mixed with mucus and undigested food, and have a bad smell.
3. Amoebic dysentery: similar to bacterial dysentery, but the symptoms of poisoning are mild, the patient may have fever of about 38 °C, abdominal pain, diarrhea, several times a day to more than 10 times, the stool is bloody mucus, or the stool is separated from the blood. Sometimes it can be completely bloody, if the number is not too much, the stool is dark red or jam-like, strange smell.
Examine
Examination of amoebic colitis
Fecal examination is an important basis for the diagnosis. It is still necessary to identify non-pathogenic amoeba protozoa after pathogen discovery. The current serological examination is very fast and is a key experiment for the diagnosis of amebiasis. About 90% of patients have serum. Antibodies with different titers can be detected by ELISA, indirect hemagglutination and indirect immunofluorescence. PCR diagnostic techniques are very effective, sensitive and specific methods.
The WHO Special Committee recommended that the cysts containing quadruplex should be detected by microscopy and should be identified as E. histolytica or Despana amoeba. The trophozoites containing red blood cells should be detected in the feces and should be highly suspected to be dissolved in the tissue. Miba; serological examination of high titer positive, should be highly suspected to be E. histolytica infection, amebic disease caused only by E. histolytica.
1. Colonoscopy: no positive results were obtained for those microscopy, serological and PCR tests, and clinically highly suspected cases, feasible colonoscopy or fiberoptic colonoscopy, about 2/3 of the symptomatic cases, rectal and The sigmoid colon mucosa can be seen with scattered ulcers of different sizes. The surface is covered with yellow pus, the edge is slightly protruding, slightly congested, the mucosa between the ulcer and the ulcer is normal, and the material is scraped from the ulcer surface for microscopic examination, and the chance of trophozoite is more.
2. X-ray barium enema examination: There are filling defects, sputum and congestion in the lesions. Although this finding is not specific, it is helpful for the identification of amoebic and intestinal cancer.
Diagnosis
Diagnosis and diagnosis of amebic colitis
Diagnostic criteria
In the fresh feces of the patient, especially in the bloody mucus, carefully search for the amoeba, once the active phagocytic amoebic trophozoites with red blood cells are found, the diagnosis can be confirmed. Once it is not found, it should be repeated several times. And strive to do bacteria and amoeba culture, microscopic examination should pay attention to heat preservation, otherwise the amoebic trophozoites are inactive, not easy to distinguish from macrophages, sigmoidoscopy is very helpful for diagnosis, especially differential diagnosis, acute phase can be Seeing the flask-like ulcer, the mucosa between the ulcers is normal, the intestinal mucosa hyperplasia, granuloma and polyps can be seen in the chronic phase, and the living tissue can be taken for pathological examination at the lesion to further determine its nature.
Differential diagnosis
Amoebic colitis should be differentiated from acute, chronic enteritis, acute, chronic bacillary dysentery, non-specific ulcerative colitis, colon cancer, etc. The most important are stool examination and sigmoidoscopy, and also should be caused by other parasite-induced enteritis. Performance identification.
Such as schistosomiasis patients, may have symptoms of abdominal pain and diarrhea, sigmoidoscopy can be seen on the intestinal mucosa scattered yellow small particles, the live tissue can be found schistosomiasis eggs, Giardia lamblia parasitic in the small intestine, can cause abdominal pain Symptoms of diarrhea, cysts and trophozoites of the worm can be found in the stool, such as duodenal drainage, and the positive rate of drainage is higher.
In the past, it has been considered for many years that the fragile binuclear amoeba parasitic in the human colon is not pathogenic, but in recent years, it has been suggested at home and abroad that the brittle dinuclear amoeba can cause gastrointestinal symptoms in some people, with abdominal pain and diarrhea. The most common, stool 2 to 4 times a day, a paste, can also be formed, the colonic mucosa has no obvious pathological changes, it has not been confirmed that it has cysts, so the route of infection is still unclear, some people think that it may pass the locust eggs or The larva is infected into the human body. This problem is worthy of further study. The fragile dinuclear amoeba trophozoite is small, 3.5~12m in diameter. Iron hematoxylin staining can be seen to have 2 nuclei. It is not difficult to nourish the tissue amoeba. The difference in body.
