Amoebiasis

Amoebiasis is the second leading cause of death from parasitic disease worldwide. The causative protozoan parasite, Entamoeba histolytica, is a potent pathogen. Secreting proteinases that dissolve host tissues, killing host cells on contact, and engulfing red blood cells, E histolytica trophozoites invade the intestinal mucosa, causing amoebic colitis. In some cases amoebas breach the mucosal barrier and travel through the portal circulation to the liver, where they cause abscesses consisting of a few E histolytica trophozoites surrounding dead and dying hepatocytes and liquefied cellular debris. Amoebic liver abscesses grow inexorably and, at one time, were almost always fatal, but now even large abscesses can be cured by one dose of antibiotic. Evidence that what we thought was a single species based on morphology is, in fact, two genetically distinct species--now termed Entamoeba histolytica (the pathogen) and Entamoeba dispar (a commensal)--has turned conventional wisdom about the epidemiology and diagnosis of amoebiasis upside down. New models of disease have linked E histolytica induction of intestinal inflammation and hepatocyte programmed cell death to the pathogenesis of amoebic colitis and amoebic liver abscess.     

Human amoebic hepatic abscess: in situ interactions between trophozoites, macrophages, neutrophils and T cells

Amoebic liver abscesses (ALA) are the most frequent and severe extraintestinal clinical presentations of amoebiasis. During the early establishment of amoebae in the liver parenchyma, as well as during the extension of the tissue necrosis, parasites interact with the parenchymal liver cells and, as a consequence of these interactions, hepatocytes can be destroyed and host immune cells can become activated. However, little is known about the nature of these interactions in the liver or about the factors involved in the local immune response. In this investigation we studied the localization of Entamoeba histolytica trophozoites, TCD4+, TCD8+ cells, CD68+ macrophages and CD15+ neutrophils in human ALA using immunohistochemical techniques. Trophozoites were found close to undamaged hepatocytes in both lysed and non-lysed areas with either sparse or abundant inflammatory infiltrate. CD8+ cells were more abundant than CD4+ T cells. CD 68+ macrophages and CD15+ neutrophils were also detected, suggesting that neutrophils, macrophages and T cells might be related to the local host immune mechanisms in ALA. We also found that E. histolytica possesses proteins recognized by antibodies raised against inducible nitric oxide synthase.     

Pyogenic liver abscess:An audit of 10 years’experience

AIM:To describe our own experience with pyogenic liver abscesses over the past 10 years and investigate the risk factors associated with failure of initial percutaneous therapy.METHODS:A retrospective study of records of 63 PLA patients presenting between 1998 and 2008 to Australian tertiary referral centre,were reviewed.Amoebic and hydatid abscesses were excluded.Demographic,clinical,radiological,and microbiological characteristics,as well as surgical/radiological interventions,were recorded.RESULTS:Sixty-...     

Macrophage requirement for host defence against experimental hepatic amoebiasis in the hamster

The role of macrophages in hepatic amoebiasis in hamsters has been investigated by means of their treatment with bacille Calmette-Guérin (BCG) for activation, and with silica for elimination of these cells. Silica-treated animals inoculated intrahepatically with 1 x 10(5) trophozoites of Entamoeba histolytica developed amoebic abscesses in the liver and more metastases to other organs than control animals, and this effect was silica-dose-dependent. In contrast, BCG-treated animals developed significantly smaller abscesses in the liver and fewer metastatic foci. These data suggest that macrophages are involved in host defence against the establishment of amoebic liver abscess and metastatic dissemination of amoebae.     

Entamoeba histolytica infection in men who have sex with men

Entamoeba histolytica infection (amoebiasis) is the second leading cause of death from parasitic diseases. Epidemiological studies from developed countries have reported an increasing prevalence of amoebiasis and of invasive infections, such as amoebic colitis, among men who have sex with men (MSM) who engage in oral-anal sex. Although most infections with E histolytica are asymptomatic, clinical manifestations of invasive amoebiasis mainly include amoebic colitis and amoebic liver abscess, which are associated with substantial morbidity and medical cost. Laboratory diagnosis of amoebiasis should be based on detection of E histolytica by use of tests with high sensitivity and specificity, such as specific amoebic-antigen or PCR-based assays. Microscopy used in routine clinical laboratories is not sensitive or specific enough for detection of E histolytica. Metronidazole or tinidazole remains the mainstay of treatment for invasive amoebiasis, followed by treatment with luminal agents to prevent relapse and transmission of E histolytica to sexual partners or close contacts.     

Amoebic liver abscess: a retrospective clinical evaluation of twenty-seven cases

Twenty-seven patients with Amobebic Liver Abscess were observed during the last two years and were analysed retrospectively with respect to diagnostic procedures and therapeutic strategies. Seven of the 27 patients had surgery and were subsequently referred to our hospital. Those patients with surgery had a longer duration of illness and hospitalization (3.3 months) compared to the other 20 patients with chemotherapy alone (2 months). Most important diagnostic parameters for extraintestinal amoebiasis were: typical clinical findings, time spent in tropical or subtropical countries, strongly positive Latex agglutination against Entamoeba histolytica antigen, and isotope and/or ultrasound scanning to confirm abscess formation in the liver. The vast majority of abscesses were found in the right liver lobe. Response to treatment with complete cure was seen in all patients, regardless of whether Metronidazole alone or combinations of Metronidazole with Chloroquine and Metronidazole and Dehydroemetine or Chloroquine and Dehydroemetine were used. There is a need for prospective therapeutic studies to compare the different drug regimen concerning side-effects, toxicity, costs, application, and duration of hospitalization. From the retrospective data it seems that surgery is not beneficial for the patients.     

118例细菌性肝脓肿临床特点分析

目的 探讨近年来细菌性肝脓肿的临床特点、病原学、诊断和治疗的变化.方法 回顾性分析1986年1月-2010年6月北京协和医院118例细菌性肝脓肿住院患者的临床资料.结果 118例平均年龄53.3岁,其中发热(97.5%)、寒战(91.5%)、右上腹痛(44.1%)是最常见的临床表现.糖尿病(41.5%)、胆系疾病(24...     

Amoebic liver abscess in Wessex--a retrospective survey of 24 cases

The clinical features and response to treatment of 24 patients with amoebic liver abscess in Wessex are presented. Two patients died before adequate treatment could be instituted, but 6 of the remaining 22 patients (27%) did not respond to single courses of conventional anti-amoebic therapy. Possible reasons for this high failure rate are discussed. It is concluded that although Metronidazole is a highly effective anti-amoebicide, there remains a place for other drugs such as Emetine. The importance of early diagnosis of Amoebic Liver Abscess is emphasised.     

Treatment of amoebic liver abscess with metronidazole alone or in combination with ultrasound-guided needle aspiration: a comparative, prospective and randomized study

Thirty-nine patients with amoebic liver abscess (ALA), admitted to the Central Hospital of Hué (Vietnam), were evaluated in a comparative, prospective and randomized study for the treatment of ALA. Adult patients with an abscess located in the right liver lobe and an abscess diameter of 6 to 10 cm were included. Bacterial abscesses were excluded by microbiological examination of abscess fluid in all patients. Nineteen patients were treated with metronidazole for 10 days alone and 20 patients were punctured under ultrasound guidance with aspiration of abscess fluid in addition to drug administration. The clinical symptoms fever, pain in right upper abdomen and liver tenderness, and the laboratory parameters erythrocyte sedimentation rate, white blood cells, haemoglobin and C-reactive protein and the abscess size were determined on the day of admission and followed during an observation period of 38 days. Improvement of liver tenderness was significantly faster in the aspiration group during the first 3 days (P < 0.001), whereas all the other parameters showed no differences between the two groups. This minor benefit is obviously not sufficient to justify routine needle aspiration and advocates drug treatment alone for uncomplicated amoebic liver abscesses with a diameter up to 10 cm located in the right liver lobe.     

Immunization with a tetramer derivative of an anti-inflammatory pentapeptide produced by Entamoeba histolytica protects gerbils (Meriones unguiculatus) against experimental amoebic abscess of the liver

Axenically grown Entamoeba histolytica produces a pentapeptide (Met-Gln-Cys-Asn-Ser) with several anti-inflammatory properties, including the inhibition of human monocyte locomotion (Monocyte Locomotion Inhibitory Factor (MLIF)). A construct displays the same effects as the native material. It remains to be seen if MLIF is used, or even produced in vivo by the tissue-invading parasite. If MLIF were to be relevant in invasive amoebiasis, immunizing against it could diminish this parasite advantage and prevent lesions. KLH-linked MLIF mixed with Freund's adjuvant was too aggressive an immunizing material to answer this question. However, immunization with a tetramer of MLIF (but not a scrambled version of MLIF) around a lysine core (MLIF-MAPS), that displays increased antigenicity, yet lacks excessive innate immunity activation, completely protects gerbils against amoebic abscess of the liver caused by the intraportal injection of virulent E. histolytica. Liver abscesses caused by Listeria monocytogenes were not prevented. Invasive E. histolytica may produce the parent protein of MLIF in vivo, and if appropriately cleaved, it may play a role in invasive amoebiasis. MLIF may join new vaccination strategies against amoebiasis.     

Amoebic liver abscess with negative serologic markers for <Emphasis Type="Italic">Entamoeba histolytica</Emphasis>: mind the gap!

A 38-year-old male German traveller returning from Asia presented with fever, night sweats and abdominal complaints. Abdominal ultrasonography revealed several fast-growing abscesses of the liver. Three blood cultures as well as serologic investigations for the detection of antibodies to Entamoeba histolytica, performed on day 3 and 7 after the onset of clinical symptoms, remained negative. Stool microscopy revealed the presence of amoeba cysts compatible with E. histolytica infection. Taking both the amoebic and bacterial etiology of the abscesses into consideration, the patient was treated with metronidazole and ciprofloxacin followed by paromomycin. Antibodies to E. histolytica tested positive shortly after anti-amoebic therapy was initiated. The patient fully recovered, and ultrasound follow-up showed complete resolution of the abscesses within 50 days. This case leads to the conclusion that amoebic liver abscess should be considered despite negative amoeba serology and that ultrasonography is an important diagnostic tool for the early diagnosis of extraintestinal amoebiasis.     

Pyogenic liver abscesses

Pyogenic liver abscess is a classic clinical entity whose presentation and management have evolved significantly with the advent of potent antimicrobials and the availability of improved diagnostic imaging. The classic triad of fever, upper right quadrant pain or fullness, and jaundice resulting from advanced pylephlebitis is now seldom seen. Despite these changes, pyogenic liver abscess remains an important clinical entity for which prompt recognition and treatment are essential to achieve a favorable outcome. This article discusses the presentation and diagnosis of and current therapy for liver abscesses.     

老年糖尿病并发细菌性肝脓肿28例诊治探讨

目的 探讨近年来老年糖尿病（DM）合并细菌性肝脓肿的临床表现、诊断和治疗要点。方法 回顾性分析28例DM并发肝脓肿病例。结果 老年DM并发肝脓肿多见于男性,以右叶及多发常见;临床表现不典型,好发于2型DM患者;胆囊炎、胆石症是主要致病因素（50％）,诊断首选B超（64．3％）。治疗方法为及时切开引流或B超引导下穿剌,同时应用有效抗生素,用胰岛素控制血糖。本病死因主要为感染及多脏器功能衰竭。结论 DM合并并肝脓肿临床表现不典型,诊断较困难。对DM伴有发热者应高度重视。控制血糖,及时治疗胆道感染是预防本病发生的重要措施。     

Hepatic amebiasis in the Kilimanjaro region. Serodiagnosis on micro-specimens of dried blood and attempts at treatment with tinidazole (fasigyn)]

Amoebic dysentery appears to be rare in the northeast of Tanzania. Hepatic amoebiasis, on the other hand, is apparently widespread since at least 200 cases are seen every year at the Kilimanjaro Christian Medical Centre. This incidence of cases enabled us to carry out trials on the spot with a new imidazole derivative, Tinidazole. Formerly the difficult diagnosis based on clinical symptoms had to be buttressed by radiological evidence and possibly by the result of puncture. Indirect fluorescent antibody tests for the diagnosis of amoebiasis were performed elsewhere on all the patients, using for this purpose microspecimens of dried blood. In 12 cases out of 34 an agglutination test with sensitized latex particles was performed on the spot. This latter test has the practical advantage of being easy to employ. It cannot, however, be considered as a screening test since it is subject to downward and upward errors. The indirect fluorescent antibody test has been found to be constantly and highly positive, certain antibody titres attaining 1/6400. This fully confirms the value of the method even under special working conditions. Seventeen of our 34 patients (2 women and 15 men ranging in age from 20 to 75 years) were treated with 2 g of Tinidazole per day in a single dose for 2 to 3 consecutive days. Puncture to evacuate pus was also performed where abscesses had collected. Tolerance on the whole was good without a single sign of cardiovascular or urinary toxicity. However, paraesthesia of the hands was observed in one case, transitory thrombocytopenia in one other patient, and increased alkaline phosphatases. Minor disorders were also observed in our series of patients: mild vertigo (7 cases), headache (6 cases), and dry mouth (2 cases). After 8 months the therapeutic results were as follows: 12 complete cures out of 17, 2 improvements with final cure probable, 3 partial failures necessitating supplementary treatment with Metronidazole (2.4 g per day for 2 days). These preliminary trials appear to the encouraging and the study is being continued with series compared with cases treated with Emetine or Metronidazole.     

Amebic colitis - differential diagnosis of ulcerative colitis and Crohn disease

Amoebic colitis rarely develops in patients who had not stayed in a country where amoebiasis is endemic. "Crohn's colitis" was diagnosed in a 33 year old female patient who never had stayed in such an area. The dramatic deterioration of the disease led to revise the early diagnosis. The reported case indicates that the conventional laboratory, endoscopic, histologic, and radiologic examinations don't prove the anamnestically unsuspected amoebic colitis. Since the correct diagnosis was verified by stool and serologic examinations, these should be performed in any doubt of a specific colitis.     

Liver abscesses secondary to sigmoid diverticulitis: report of four cases

INTRODUCTION: Pyogenic liver abscess often revealed by right sided abdominal pain and fever is a serious and life-threatening pathology. Biliary tract disease is the origin of the abscess in most cases but sometimes remains unidentified. A sigmoid septic source sometimes paucisymptomatic or hidden by an immunosuppressive treatment must be looked for. EXEGESIS: Here are four observations of liver abscesses, which are secondary to unknown sigmoiditis. The etiologic diagnosis was made either by abdomino-pelvic computed tomography or by enema with water-soluble products completed by a coloscopy. Each patient's liver abscesses were emptied by aspiration or catheter drainage in conjunction with antibiotics. Surgical treatment of sigmoiditis was performed either at the same time or later. CONCLUSION: Any liver abscess of unknown origin must lead to a search for unknown or disguised septic sigmoid pathology. Most of the time, injected abdomino-pelvic computed tomography makes the diagnosis possible, but enema associated with coloscopy is sometimes necessary.     

Hepatic amebiasis: study of 152 cases

The purpose of this study was to describe and analyse retrospectively the clinical, serological, anatomical and evolutive features of 152 cases of hepatic amebiasis in young adults, treated and followed up in France from 1969 to 1983. The disease was revealed 3 times out of 4 by tender hepatomegaly with fever, but only in 6 cases by complications. Serological tests (immunofluorescence or hemagglutination) were always positive for amebiasis, whereas Entamoeba histolytica was absent from stools in 96.7 p. 100 of the cases. Hepatic amebiasis always caused a hepatic abscess: in these cases, the superiority of ultrasonography over all other diagnostic methods was confirmed, especially concerning the detection of multiple abscesses (47 p. 100). Complete recovery was obtained by medical treatment in 117 cases, either alone (98 cases), or combined with needle aspiration (19 cases). Nitro-imidazoles are the simplest treatment, but nevertheless in 5 cases they were not effective. These patients were then treated with dehydroemetine, associated in 2 cases with surgery. Four patients relapsed at mid or long-term after apparent recovery, in the absence of any obvious reinfection. A significant correlation between the course of the treated disease and the size and number of abscesses was demonstrated: it was possible to define a group characterized by a slow and/or complicated course (with single abscess of the right lobe whose diameter is equal to or greater than 10 cm, or multiple abscesses). The pathogenesis of hepatic amebiasis is not yet fully understood.     

Pyogenic liver abscess as a complication of Crohn's disease

Pyogenic liver abscess in patients with Crohn's disease is not common, but the mortality has been reported to be high if diagnosis and treatment is delayed. Intra-abdominal abscesses, fistulous disease, and steroid therapy have all been reported to be important predisposing factors in the pathogenesis of this entity. We present a patient with Crohn's disease in whom multiple abscesses were encountered in the right lobe of the liver. The diagnosis of liver abscess was established by abdominal computed tomography and the patient was treated by percutaneous catheter drainage. Awareness of this rare complication is important because diagnosis is difficult to make and a high index of suspicion is required. Once suspected, aggressive diagnostic workup and treatment is indicated. Most patients with liver abscess can be successfully managed by percutaneous catheter drainage combined with antibiotic therapy if it is diagnosed before extensive necrosis has occurred.     

CT-guided Percutaneous Aspiration and Catheter Drainage of Pyogenic Liver Abscesses

Surgical drainage has been the accepted method of treatment for pyogenic liver abscesses. Modern imaging techniques have revolutionized the diagnosis and management of liver abscesses. Percutaneous aspiration and drainage have been reported as a treatment modality of pyogenic liver abscesses in the literature before. We treated 15 patients with pyogenic liver abscesses by percutaneous aspiration and drainage. All patients responded except two. No mortality was observed. Review of the literature and our experience with 15 patients suggest that because of the high recovery rate and few complications percutaneous aspiration and drainage should be the first line of treatment in the management of pyogenic liver abscesses.     

阿米巴肝脓肿36例临床分析

[目的 ]分析阿米巴肝脓肿的临床特点、误诊情况和内外科治疗对患者预后的影响。 [方法 ]采用回顾性调查方法 ,分析 1982年 9月～ 1997年 3月在我院确诊的 36例阿米巴肝脓肿患者的临床特点、诊治和转归情况。 [结果 ]主要临床表现为上腹痛 (86 1% )、发热 (86 1% )、肝肿大伴触痛 (83 3% )和右肋间压痛(5 8 3 % )。实验室检查 ,外周血白细胞升高 (6 1 1% )及血沉增快 (88 5 % )等。 92 6 %的患者血阿米巴抗体阳性。B超声检查 ,单个脓肿及右叶肝脓肿均为 75 %。全部病例均用甲硝唑治疗 ,其中 ,2 7例患者同时行肝脓肿穿刺抽脓。治疗后 ,痊愈 10例 ,显效 2 5例 ,总有效率为 97 2 %。 1例患者死于肝功能衰竭。 [结论 ]单用抗阿米巴药物治疗对于小肝脓肿疗效好 ,如肝脓肿较大应同时行肝脓肿穿刺引流