Amebic liver abscess

E. histolytica invades mucosal cells of colonic epithelium, producing the classic flask-shaped ulcer in the submucosa. The trophozoite toxin has a cytocidal effect on cells. If the trophozoite gets into the portal circulation, it will be carried to the liver, where it produces abscess and periportal fibrosis. Liver abscesses are more common in men than women and are rarely seen in children. Amebic ulcerations can affect the perineum and genitalia, and abscesses may occur in the lung and brain. 

Erosion of liver abscesses can result in peritonitis. Liver abscesses that are located in the right lobe can spread to the lungs and pleura. Pericardial infection, although rare, may be associated with extension of the amebic abscesses from the liver. 

Whereas the highest serum IgG and IgM concentrations were found in those patients with amebic liver abscesses, their IgA levels were within normal limits. 

Amebiasis For the treatment of intestinal amebiasis and amebic liver abscess caused by Entamoeba histolytica in adults and pediatric patients older than 3 years of age. 

Trophozoites may spread to the liver through the portal vein and produce acute amebic hepatitis, or more rarely, the trophozoites may encyst and produce an amebic liver abscess many years later. On rare occasions, amebic abscesses are found in other organs, such as the lungs or the brain. 

The use of emetine and dehydroemetine is limited to unusual circumstances in which severe amebiasis warrants effective therapy and metronidazole cannot be used. Dehydroemetine is preferred over emetine because of its somewhat better toxicity profile. The drugs should be used to treat amebic dysentery or amebic liver abscess for the minimum period needed to relieve severe symptoms (usually 3-5 days). 

Chloroquine [KLOR oh kwin] is used in conjunction with metronidazole and diloxanide furoate to treat and prevent amebic liver abscesses. It eliminates trophozoites in liver abscesses, but it is not useful in treating luminal amebiasis. Chloroquine is also effective in the treatment of malaria and is more fully described in the malaria section (see p. 349). 

G. Percutaneous catheter drainage of amebic liver abscesses with and without intrahepatic biliary communication a comparative study. Europ. X Radiol. 1995 20 61-64... 

Elizondo, G., Weissleder, R., Stark, D.D., Todd, L.E., Compton, C., Wittenberg, J., Ferruci, J.T.jr. Amebic liver abscess diagnosis and treatment evaluation with MR imaging. Radiology 1987 165 795-800... 

A. M. Perforated amebic liver abscesses successful percutaneous treatment. Radiology 1989 170 195-197... 

Maltz, G., Knaner, CJM. Amebic liver abscess a 15-year experience. Amer. J. Gastroenterol. 1991 86 704—710... 

Mondragon-Sanchez, R., Cortes-Espinoza, T., Alonzo-Fierro, Y., Labra-Villalobos, MJ., Maldonado, R.B. Amebic liver abscess a 5-year Mexican experience with a multimodality approach . Hepato-Gastro-enterol. 1995 42 473 -477... 

Sharma, M.P., Dasarathy, S., Yerma, N., Saksena, S., Shnkla, D.K. Prognostic markers in amebic liver abscess a prospective study. Amer. X Gastroenterol. 1996 91 2584-2588... 

Liver abscesses that are located in the right lobe can spread to the lungs and pleura." " Pericardial infection, although rare, may be associated with extension of the amebic abscess from the left lobe of the liver. Erosion of liver abscesses also present as peritonitis." " Review of the patient s history and recent travel cannot be overemphasized. Intestinal amebiasis is diagnosed by demonstrating E. histolytica cysts or trophozoites (may contain ingested erythrocytes) in fresh stool or from a specimen obtained by... 

Hughes MA, Petri WA Jr. Amebic liver abscess. Infect Dis Clin North Am 2000 14 565-581. 

Hoffner R, Kilaghbian T, Esekogwa VI, Henderson SO. Common presentations of amebic liver abscess. Ann Emerg Med 1999 34 351-355. 

Akgun Y, Tacyildiz 1, Celik Y. Amebic liver abscess Changing trends over 20 years. World J Surg 1999 23 102-106. 

HBeAg—Correlates with viral proliferation and infectivity. D. Amebic Liver Abscesses... 

Metronidazole is indicated in the treatment of symptomatic trichomoniasis in females and males when the presence of the trichomonad has been confirmed by appropriate laboratory procedures and in the treatment of asymptomatic females when the organism is associated with endocervitis, cervicitis, or cervical erosion. Metronidazole is also indicated in the treatment of acute intestinal amebiasis (amebic dysentery and amebic liver abscess). It is indicated in the treatment of serious infections caused by susceptible anaerobic bacteria. Indicated surgical procedures should be performed in conjunction with metronidazole therapy. In a mixed aerobic and anaerobic infection, antibiotics appropriate for the treatment of the aerobic infection should be used in addition to metronidazole. 

Other potential virulence factors associated with invasion by E. histolytica include a metallocollagenase and phospholipases (58,70). As a group, the virulence factors identified in extracts or secretions of pathogenic E. histolytica can explain in large part the cytolysis and tissue destruction that characterize E. histolytica invasion. Host neutrophils also contribute to the tissue destruction seen in amebic liver abscesses (71). 

Perez-Tamayo, R., Martinez, R. D., Montfort, I., Becker, I., Tello, E. and Perez-Monfort, R. (1991) Pathogenesis of acute experimental amebic liver abscess in hamsters. J. Parasitol. IT. 982-988. 

Amebiasis ajfects 10% of the world s population. In the U.S., amebiasis is usually seen in those living in crowded, unsanitary conditions. Entamoeba dispar accounts for 90% of human infections and E. histolytica/or only 10%, but only E. histolytica causes human disease. Humans are the only known hosts for these protozoa, which are transmitted almost exclusively by the fecal-oral route. E. histolytica cysts ingested from contaminated food or water transform into trophozoites that reside in the large intestine. Many individuals infected with E. histolytica are asymptomatic but excrete infectious cysts, making them a source for further infections. In others, E. histolytica trophozoites invade the colonic mucosa with resulting colitis and bloody diarrhea (amebic dysentery). Rarely, E. histolytica trophozoites invade through the colonic mucosa and reach the liver via the portal circulation, where they establish an amebic liver abscess. 

Chloroquine is directly toxic to E. histolytica trophozoites and is highly concentrated within the liver, making it effective for amebic liver abscess. It is used only when metronidazole or another nitroimidazole is either contraindicated or unavailable. Chloroquine is not effective against intestinal amebiasis because it only attains low concentrations in the colon patients receiving chloroquine for amebic liver abscess also should receive paromomycin or iodoquinol to eliminate intestinal colonization. 

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