Amebiasis

(Entamoebiasis)

A amebiasis is an infection with Entamoeba histolytica. They often asymptomatic, but symptoms vary from mild diarrhea to severe dysentery. Extra-intestinal infections such include. B. liver abscesses. The diagnosis is made by the detection of E. histolytica in stool samples or serologically. The treatment of symptomatic disease occurs with metronidazole or tinidazole, followed by paromomycin or other substances which are active against cysts in the lumen.

Three types of Entamoeba are morphologically indistinguishable, but molecular techniques show that they are different ways:

A amebiasis is an infection with Entamoeba histolytica. They often asymptomatic, but symptoms vary from mild diarrhea to severe dysentery. Extra-intestinal infections such include. B. liver abscesses. The diagnosis is made by the detection of E. histolytica in stool samples or serologically. The treatment of symptomatic disease occurs with metronidazole or tinidazole, followed by paromomycin or other substances which are active against cysts in the lumen. Three types of Entamoeba are morphologically indistinguishable, but molecular techniques show that they are different ways: E. histolytica (pathogens) E. dispar (non-pathogenic colonizers, often) E. moshkovskii (uncertain pathogenicity) The disease is caused by E. histolytica causes and tends to occur in regions with poor socio-economic and sanitary conditions. Most infections occur in Central America, western South America, Western and Southern Africa and the Indian subcontinent. In the industrialized countries (eg. B. USA), occur most cases among new immigrants and travelers returning from endemic areas, on. worldwide each year develop an estimated 40-50 million people a amoebic colitis or extraintestinal disease and the death of about 40,000 to 70,000. Pathophysiology Entamoeba sp is in 2 forms: the trophozoite cyst The movable trophozoites feed on bacteria and tissues divide and colonize the lumen and the mucosa of the colon and penetrate occasionally invasive tissues and organs in a. Trophozoites are primarily present in liquid stool samples, but die quickly outside the body. Some trophozoites in the colonic lumen transform into cysts, which are excreted in the stool. Cysts are prevalent in molded chair and are very environmentally resistant. They can be spread directly from person to person or indirectly through food and water. A amebiasis can also be sexually transmitted through oral-anal contact. E. histolytica trophozoites may attach to colonic epithelial cells and leukocytes kill them and can lead to bloody and mucous diarrhea, but with few leukocytes in the stool. Trophozoites also secrete proteases that degrade extracellular matrix and allow penetration into the intestinal wall and the further spread. Trophozoites can spread via the portal system and cause necrotizing liver abscesses. The infection can be spread by direct from the liver to the right lung and the pleural space or – rarely – hematogenous in the brain and spread to other organs. Symptoms and signs Most infected people have no symptoms, but divorced chronic cysts in the chair. The main symptoms of tissue invasion made for. B. from intermittent diarrhea and constipation, bloating and crampy abdominal pain. There may be a defense power of the liver or the ascending colon, and the stool may contain mucus and blood admixtures. Amoebic dysentery amoebic dysentery occurs in the tropics common and manifests itself in episodes often semi-solid bowel movements, which often contains blood, mucus, and live trophozoites. The abdominal symptoms range from mild guarding up to violent abdominal pain with high fever and toxic systemic symptoms. In an amoebic there is often an abdominal guarding. Between relapses, patients complain of abdominal cramps and liquid or very soft stools, but it can also lead to a loss of weight and anemia. It may experience discomfort, reminiscent of appendicitis. Is a surgical procedure performed in these cases, this can lead to peritoneal spread of amoebas führen.Chronische amoeba infection This infection can mimic inflammatory bowel disease and present themselves as intermittent nichtdysenterische diarrhea with abdominal pain, mucus deposition, flatulence and weight loss. A chronic infection can also be used as soft, palpable resistance or Annular lesion (Amöbom) in the cecum and ascending colon manifestieren.Extraintestinale amoebic diseases Extraintestinal diseases arise from an infection of the colon and may involve any organ, a liver abscess is the most common. There is usually a single liver abscess in the right lobe. It may manifest in patients without pre-existing symptoms, is more common in men than in women (7: 1-9: 1), and may develop insidiously. The complaints made u. a. from pain or pressure on the liver, which may spread to the right shoulder occasionally, as well as from intermittent fever, sweating, chills, nausea, vomiting, weakness and weight loss. Jaundice rarely and usually mild occurs. The abscess may perforate the subphrenic space, the right pleural cavity, right lung, or other adjacent organs (eg. B. pericardium). Occasionally, skin lesions are observed, particularly in chronic infections in the perianal and buttock area, but also in resulting from trauma or surgical wounds. Diagnosis intestinal infection: Microscopic examination and, if available, enzyme immunoassay of the chair Extraintestinal infection: imaging techniques and serological tests or a therapeutic trial A nichtdysenterische amebiasis can be misdiagnosed as irritable bowel syndrome, regional enteritis, or diverticulitis. A right-side Kolonraumforderung can be mistaken for cancer, tuberculosis, actinomycosis, or a lymphoma. A amoebic dysentery may be confused with shigellosis, salmonellosis, schistosomiasis, or ulcerative colitis. In an amoebic dysentery the stool is usually less frequent and less watery than a bacterial dysentery. Characteristic are thick mucus and blood in. In contrast to the bowel movement in shigellosis, salmonellosis and ulcerative colitis amebic stools do not contain large amounts of white blood cells, as these are lysed by trophozoites. A amebiasis of the liver and a Amöbenabszess must be differentiated from other hepatic infections and tumors. The diagnosis of amebic is supported by the detection of Amöbentrophozoiten, cysts, or both in fecal or tissue; However, pathogenic E. histolytica are morphologically indistinguishable from the non-pathogenic E. dispar and E. moshkovskii. Specific DNA detection tests for E. histolytica have been developed. The DNA tests are available from the Centers for Disease Control and Prevention (CDC) and are likely to be more readily available in the future in reference laboratories. In patients with a Amöbenleberabszess serology is positive in approximately 95% of patients, in patients with active intestinal infection> 70% and in asymptomatic carriers to only 10%. Enzyme immunoassay (EIA) is most commonly used. Existing antibody titers can confirm histolytica infection with E., but may persist for months to years and make a distinction between an acute and a previous infection in residents of areas with a high prevalence of infection impossible. Therefore are useful serological tests if a previous infection is probably considered less (z. B. travelers to endemic areas). Intestinal infection The identification of intestinal amoeba can an investigation of 3-6 stool samples using enrichment techniques require (see table: Notes on extraction, processing, storage and shipment of specimens for microscopic diagnosis of parasitic infections). Antibiotics, antacids, antidiarrheals, enemas and intestinal x-ray contrast agent can affect the rate of detection of parasites and should not be given prior to the examination of the chair. E. histolytica must be distinguished from E. dispar and E. moshkovskii as well as other non-pathogenic amoebae such as E. coli, E. hartmanni, Endolimax nana and Iodamoeba bütschlii. PCR-based tests and an enzyme immunoassay for fecal antigens are sensitive and distinguish E. histolytica from nonpathogenic amoeba. In symptomatic patients show proctoscopy often characteristic flask-shaped mucosal lesions, one of which won material and aspirates should be examined for trophozoites. Biopsy specimens from rectosigmoid lesions may also trophozoites aufweisen.Extraintestinale infection This infection is difficult to diagnose. Stool tests are usually negative, and the detection of trophozoites from aspirated pus is rarely successful. If you suspect a liver abscess, a sonography, CT or MRI scan should be performed. Despite comparable sensitivity none of these techniques can reliably distinguish between a Amöbenabszess and a pyogenic abscess. A fine needle aspiration biopsy is performed only in lesions of unknown causes and in lesions with threatening rupture and lesions that respond poorly to drug therapy. The abscesses contain thick, semi-liquid material with yellowish to dark chocolate brown color. A fine needle biopsy may show necrotic tissue, moving amoebas are difficult to find in Abszessmaterial, and amoeba cysts are not present. The experimental administration of an amoeba-effective antibiotic is often diagnostically helpful in a Amöbenleberabszess. Tips and risks Microscopic examination of the stool is usually negative in patients with extra-intestinal amebiasis. Therapy First metronidazole or tinidazole iodoquinol, paromomycin or subsequently diloxanide furoate for eradication of the cyst. For mild to moderate gastrointestinal symptoms, compared oral metronidazole is 500 to 750 mg 3 times daily in adults (12-17 mg / kg three times daily in children) is recommended for 7-10 days. Metronidazole should not be given during pregnancy. Alcohol consumption should be avoided because the substance has a disulfiramartige effect. Alternatively, tinidazole can 2 g p.o. (50 mg / kg [maximum 2 g] po 1 times daily in children> 3 years) can be used for 3 days 1 times daily in adults. When taken with alcohol, tinidazole also has a disulfiramähnliche effect, and it should not’m used during pregnancy. However, it is better tolerated in terms of gastrointestinal side effects usually than metronidazole. In severe intestinal and extra-intestinal amebiasis oral metronidazole is (kg 12-17 mg / 3 times a day in children) used 750 mg three times daily in adults over 7-10 days. Alternatively, tinidazole can 2 g p.o. (50 mg / kg [maximum 2 g] po 1 times daily in children> 3 years) can be used for 5 days 1 times daily in adults. In both cases, a metronidazole or Tinidazolzyklus should be followed by a second oral substance to eradicate residual cysts in the lumen. Options are iodoquinol 650 mg po 3 times a day after meals in adults (10-13 mg / kg [maximum of 2 g / day] po three times daily in children) for 20 days paromomycin 8-11 mg / kg p.o. 3 times a day with meals for 7 days diloxanide furoate 500 mg po 3 times daily in adults (7 mg / kg po tid in children) for 10 days diloxanide furoate is not commercially available in Germany and the USA. Therapy should further include a rehydration with fluids and electrolytes, and other supportive measures. Asymptomatic persons leaving E. histolytica cysts should be treated with paromomycin, iodoquinol or diloxanide furoate (dosage: s o..). Although metronidazole and tinidazole have some efficacy against E. histolytica cysts, this is not enough to use them for eradication of cyst. Infection with E. dispar or E. moshkovskii does not require therapy. However, when fecal antigen or PCR-based tests to distinguish them from E. histolytica are not available, the decision to treat clinically done (eg., by the likelihood of exposure to E. histolytica). be-a prevention must Contamination of food or water with human waste prevents problem, particularly due to the high incidence of asymptomatic carriers. In developing countries, uncooked foods, especially salads and vegetables, as well as potentially contaminated water and ice should be avoided. Boiling water destroys E. histolytica cysts. The effectiveness of chemical disinfection with iodine or chlorine-containing components depends on the water temperature and the amount of organic Débris from it. By portable filtration systems protection varying degrees can be achieved. In the development of a vaccine will continue to work, so far, such is not yet available. Important points E. histolytica usually caused dysentery, but sometimes liver abscesses. The diagnosis of intestinal infection is done with stool antigen tests or microscopy. The diagnosis of extra-intestinal infections is done with serological tests that are most helpful when a previous infection is considered unlikely (z. B. travelers to endemic areas) or with a therapeutic trial of a Amebicids. Treatment is with metronidazole or tinidazole to eliminate amoebas, followed by iodoquinol or paromomycin to kill cysts in the intestine.

Health Life Media Team

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