Amebic liver abscess is the most common extraintestinal manifestation of infection with Entamoeba histolytica. It is a common disease, especially in endemic areas, but it is a rare cause of inferior vena cava (IVC) obstruction, with only a few cases appearing in the literature. The authors describe a case of amebic liver abscess in a patient who developed a rare vascular complication of inferior vena cava thrombosis. The case responded to conservative treatment and radiological intervention.
A 38 year old gentleman presented with fever and right hypochondrial pain. On further evaluation he was detected to have an amoebic liver abscess (ALA) in the right lobe of the liver. The abscess yielded anchovy sauce pus on percutaneous drainage. Following the percutaneous drainage the patient developed tachycardia. Electrocardiogram revealed atrial flutter with rapid ventricular rate and ST elevation in all leads suggestive of pericarditis. The atrial flutter was reverted to sinus rhythm by cardioversion. The patient then had an uncomplicated convalescence. Amoebic pericarditis, though rare, is a serious complication of amoebic liver abscess. Pericardial complications are usually seen with left lobe liver abscess due to its proximity. Both pericarditis and cardiac arrhythmias due to amoebic liver abscess especially from right lobe are very rare.
We reviewed 204 cases of liver abscess seen between 1970 and 1985. Ninety were found to be amoebic, 24 pyogenic and one tuberculous. The cause of the abscesses in the remaining 89 patients was not established. The patients were predominantly male, Indians, and in the 30-60 age group. The majority of patients presented with fever and right hypochondrial pain. The most common laboratory findings were leucocytosis, hypoalbuminaemia and an elevated serum alkaline phosphatase. Amoebic abscesses were mainly solitary while pyogenic abscesses were mainly multiple. Complications were few in our patients and included rupture into the pleural and peritoneal cavities and septicaemic shock. An overall mortality of 2.9% was recorded. The difficulty in diagnosing the abscess type is highlighted. The single most important test in helping us diagnose amoebic abscess, presumably the most common type of abscess in the tropics, is the Entamoeba histolytica antibody assay. This test should be used more frequently in the tropics.
Crude soluble antigen (CSA) produced from Entamoeba histolytica trophozoite is conventionally used for serodiagnosis of invasive amoebiasis. However, high background seropositivities by CSA-assay in endemic areas complicate the interpretation of positive result in clinical settings. Instead, incorporating a second assay which indicates active or recent infection into the routine amoebic serology could possibly complement the limitations of CSA-assay. Hence, the present study aimed to evaluate the diagnostic efficacies of indirect ELISAs using CSA and excretory-secretory antigen (ESA) for serodiagnosis of amoebic liver abscess (ALA). Reference standard for diagnosis of ALA at Hospital Universiti Sains Malaysia is based on clinical presentation, radiological imaging and positive indirect haemagglutination assay (titer ≥256). Five groups of human serum samples collected from the hospital included Group I - ALA diagnosed by the reference standard and pus aspirate analysis using real-time PCR (n=10), Group II - ALA diagnosed by the reference standard only (n=41), Group III - healthy control (n=45), Group IV - other diseases control (n=51) and Group V - other infectious diseases control (n=31). For serodiagnosis of ALA serum samples (Group I and II), CSA-ELISA showed sensitivities of 100% for both groups, while ESA-ELISA showed sensitivities of 100% and 88%, respectively. For serodiagnosis of non-ALA serum samples (Group III, IV and V), CSA-ELISA showed specificities of 91%, 75% and 100%, respectively; while ESA-ELISA showed specificities of 96%, 98% and 100%, respectively. Indirect ELISAs using CSA and ESA have shown distinct strength for serodiagnosis of ALA, in terms of sensitivity and specificity, respectively. In conclusion, parallel analysis by both assays improved the overall efficacies of amoebic serology as compared to either single assay.
A case of amoebiasis with colonic perforation and ruptured liver abscess is reported. It is rare for both these complications to occur in the same patient. The management is described and the literature reviewed
The protein profile of serum samples from patients with amoebic liver abscess (ALA) was compared to those of normal individuals to determine their expression levels and to identify potential surrogate disease markers. Serum samples were resolved by two dimensional electrophoresis (2-DE) followed by image analysis. The up and down-regulated protein spots were excised from the gels and analysed by MS/MS. The concentration of three clusters of proteins i.e. haptoglobin (HP), α1-antitrypsin (AAT) and transferrin in serum samples of ALA patients and healthy controls were compared using competitive ELISA. In addition, serum concentrations of HP and transferrin in samples of patients with ALA and pyogenic liver abscess (PLA) were also compared. The results of the protein 2-DE expression analysis showed that HP cluster, AAT cluster, one spot each from unknown spots no. 1 and 2 were significantly up-regulated and transferrin cluster was significantly down-regulated in ALA patients' sera (p<0.05). The MS/MS analysis identified the unknown protein spot no.1 as human transcript and haptoglobin and spot no. 2 as albumin. Competitive ELISA which compared concentrations of selected proteins in sera of ALA and healthy controls verified the up-regulated expression (p<0.05) of HP and the down-regulated expression (p<0.01) of transferrin in the former, while there was no significant difference in AAT expression (p> 0.05). However, when ALA and PLA samples were compared, competitive ELISA showed significant increased concentration of HP (p<0.05) while transferrin levels were not different. In conclusion, this study showed that HP is a potential surrogate disease marker for ALA.
This is a ten year (1999-2008) retrospective study of amebiasis in patients admitted to UMMC. A total of 34 cases were analyzed. The most common were amebic liver abscess 22(65%) and the rest were amoebic dysentery 12(35%). Majority of the cases occurred among Malaysians 29(85%), with Chinese 14(41%), followed by the Malays 9(26%) and the Indians 6(18%). Foreigners made up of one Indonesian, one Pakistani and three Myanmarese and constituted 5(15%) of the total cases. Males 24(71%) were more commonly affected. Most of the cases occurred between the age group of 40-49 years, 8(23%) and 60 years and above, 8(23%). Age group of 20-50 years constituted 20(60%) of the cases. The most common clinical presentations were fever with chills and rigors 26(76%), diarrhoea 20 (59%), right hypochondrium pain 17(50%), abdominal pain 17(50%), hepatomegaly 16 (47%) and jaundice 7(20%). All were discharged well after treatment except for one case of death in a 69-year-old Chinese male with amebic liver abscess.
Independent evaluations of XEh Rapid®, an IgG4-based rapid dipstick test, were performed to assess its diagnostic performance to detect amebic liver abscess (ALA) using 405 samples at seven laboratories in four countries. The test showed high diagnostic specificity (97-100%) when tested with samples from healthy individuals (n = 100) and patients with other diseases (n = 151). The diagnostic sensitivity was tested with a total of 154 samples, and the results were variable. It was high in three laboratories (89-94%), and moderate (72%) and low (38%) in two other laboratories. Challenges and issues faced in the evaluation process are discussed. Nevertheless, XEh Rapid is promising to be developed into a point-of-care test in particular for resource-limited settings, and thus merits further confirmation of its diagnostic sensitivity.
To compare the efficacy of three different tissue stains, namely haematoxylin and eosin (H&E), periodic-acid Schiff (PAS) and immunohistochemical (IHC) stains for detection of Entamoeba histolytica (E. histolytica) trophozoites in abscessed liver tissues of hamster.
Amoebic liver abscess (ALA) is the most frequent clinical presentation of extra-intestinal amoebiasis. The diagnosis of ALA is typically based on the developing clinical symptoms, characteristic changes on radiological imaging and serology. Numerous serological tests have been introduced for the diagnosis of ALA, either detecting circulating amoebic antigens or antibodies. However those tests show some pitfalls in their efficacy and/or the preparation of the tests are costly and tedious. The commercial IHA kit that used crude antigen was reported to be useful in diagnosis of ALA, however high antibody background in endemic areas may cause problems in its interpretation. Thus, discovery of well-defined antigen(s) is urgently needed to improve the weaknesses of current serodiagnostic tests.
Amoebiasis is a parasitic infection caused by the
intestinal protozoan Entamoeba histolytica, most
prevalent in developing countries. It results in 40,000 to
100,000 deaths each year from amoebic colitis and extra
intestinal infections. Amoebic liver abscess (ALA)
is the most common extra intestinal site of infection
with an incidence of between 3% and 9% of all cases of
amoebiasis. Ultrasound which has a sensitivity of more
than 90% for detecting ALA is highly recommended
as an initial investigation followed by serological
demonstration of circulating antibodies specific to
Entamoeba histolytica.
Amoebic serodiagnosis at Hospital Universiti Sains Malaysia (HUSM), Kelantan employs an indirect haemagglutination assay (IHA) which detects anti-Entamoeba histolytica antibodies in patients' serum samples. In an amoebiasis endemic area such as Kelantan, interpretation of a positive IHA result can be problematic due to the high background antibody levels. The TechLab E. histolytica II ELISA is a commercial kit for detection of specific Gal/GalNAc lectin antigen in stool samples, and has been reported to be able to detect the antigen in serum samples from patients with amoebic liver abscess (ALA). Thus in this study we investigated the usefulness of TechLab E. histolytica II ELISA for diagnosis of ALA by comparing it with IHA. This is a cross sectional study involving 58 suspected ALA patients who were admitted to the surgical ward, HUSM, Kelantan. The diagnosis of ALA was established based on clinical symptoms and signs, ultrasound and/or CT scan results. The serum specimens obtained from the patients were tested with IHA (Dade Behring Diagnostics, Marburg, Germany) and TechLab E. histolytica II ELISA (Techlab, Blacksburg, Virginia, USA) according to the manufacturers' instructions. Of the 58 patients, 72.4% (42) were positive by IHA and only 8.6% (5) were positive by the TechLab E. histolytica II ELISA. Agreement between the IHA and ELISA was poor (kappa value 0.019, p=0.691). There was also no correlation between ELISA results and IHA antibody titers. The TechLab E. histolytica II ELISA was not sensitive in detecting amoebic antigen in samples from ALA patients. In addition the results of the test did not correlate with the IHA anti-E. histolytica antibody titres. Therefore, the TechLab E. histolytica II ELISA was found not to be useful for serological diagnosis of ALA at HUSM.
Entamoeba histolytica is the second major cause of liver abscess disease in humans, particularly in developing countries. Recently, DNA molecular-based methods have been employed to enhance the detection of E. histolytica in either pus or stool specimens. In this study, the results of real-time polymerase chain reaction (PCR) to detect E. histolytica DNA in pus from liver abscess cases were compared with those of indirect hemagglutination assay on the corresponding serum samples. Bacterial cultures were also performed on the pus samples for the diagnosis of pyogenic liver abscess. The real-time PCR detected E. histolytica DNA in 23 of 30 (76.7%) pus samples, when compared with 14 of 30 (46.7%) serum samples in which anti-Entamoeba antibodies were detected by indirect hemagglutination assay and 4 of 30 (13.3%) pus samples that showed bacterial infection by culture. The use of real-time PCR is a promising detection method for diagnosis and epidemiology assessment of amoebic liver abscess.
Amoebiasis, caused by Entamoeba histolytica, is one of the leading parasitic infections in the world. This study was aimed at profiling antigenic membrane proteins of a virulent variant of E. histolytica HM-1:IMSS. The membrane proteins were extracted using ProteoExtract® kit (Merck, Darmstadt, Germany) or conventional method, separated using OFFGEL 3100 fractionator (Agilent Technologies, Santa Clara, California), followed by SDS-PAGE and Western blot analysis. Selected antigenic membrane proteins were identified using LC-ESI-MS/MS. Subsequently, the proteins were classified according to their biological processes and predictions were made on membrane and membrane-associated proteins. When the proteins were probed with pooled sera from amoebic liver abscess (ALA) patients, 10 and 15 antigenic proteins with molecular weights 25 to 200 kDa were identified using the ProteoExtract® kit and conventional method, respectively. LC-ESI-MS/MS identified 13 antigenic proteins, and both extraction methods predicted six of them as membrane and membrane-associated proteins. The topmost biological processes which comprised of six proteins were involved in cellular processes.. These antigenic membrane proteins merit further investigations as potential candidates for vaccine studies.
Entamoeba histolytica causes amoebic diarrhoea, colitis and liver abscess (ALA). Diagnosis of ALA is difficult, as most patients do not have simultaneous intestinal amoebic infection. At Hospital Universiti Sains Malaysia (HUSM), diagnosis of ALA relies on a combination of clinical findings, ultrasound examination of the liver and serodiagnosis using a commercial kit. In this study, two in-house indirect ELISAs were developed and evaluated. One of the in-house assays utilises E. histolytica crude soluble antigen (CSA) to detect serum IgG specific to the parasite whereas the other uses E. histolytica ether extract antigen (EEA). Preparation of CSA requires a sonicator to lyse the amoeba whereas EEA was prepared by chemically solubilizing the trophozoites. Based on the cut-off value of mean optical density + 3SD, CSA-ELISA showed 100% (24/24) sensitivity and 93.33% (210/225) specificity; while EEA-ELISA showed 91.67% (22/24) sensitivity and 95.11% (214/225) specificity. In conclusion, both the in-house indirect ELISAs were found to be efficacious for diagnosis of ALA; and the EEA is easier to prepare than the commonly used CSA.
The indirect hemagglutination test was used to study antibody titers to Entamoeba histolytica in different Malaysian populations. Eighty-seven percent of Orang Asli (western Malaysian aborigines) adults and 79% of Orang Asli children with acute amebic dysentery were seropositive. However, significantly fewer children (39%) with amebic dysentery had high titer responses (titer greater than or equal to 1:1,280) than did adults with amebic dysentery (76%). No correlation between proctoscopic severity and amebic titer was found. Forty-four percent of asymptomatic family members were seroresponders. Satak, an Orang Asli village located near towns, had significantly more seroresponders (32%) than did the isolated, deep jungle village, Belatim (4%).