Diagnosis Of Amoebic Liver Abscess Research Articles

Evaluation of Molecular Assays for Diagnosis of Amoebic Liver Abscess in India with Bayesian Latent Class Analysis.

Amoebic liver abscess (ALA) is the most common extra-intestinal complication of Entamoeba histolytica, accounting for 50,000 deaths annually, and is endemic in South Asia. Diagnosis based on microscopic examination is insensitive, and serological assays are not discerning of current infections in endemic settings with high exposure. For a rapid and confirmatory laboratory diagnosis of ALA, the performance of a polymerase chain reaction (PCR), quantitative real time PCR (qPCR), digital droplet PCR (ddPCR), and a loop-mediated isothermal amplification (LAMP) assay that detects E. histolytica DNA in liver abscess pus, and a lectin antigen detection ELISA were evaluated against clinical diagnosis (based on predefined criteria) as the gold standard. Owing to the lack of a laboratory gold standard, a Bayesian latent class analysis approach was also used to determine sensitivity and specificity of these assays. In the latent class analysis, qPCR and ddPCR showed the highest sensitivity (98% and 98.1%) and specificity (both 96.6%), and although clinical diagnosis had a comparable sensitivity to qPCR and ddPCR (95.2%), poorer specificity (64.3%) was seen. Kappa agreement analysis showed that qPCR and ddPCR had a perfect agreement of 1 followed by an agreement of 0.76 (95% CI: 0.64-0.88) with PCR. Considering the performance characteristics and relative ease of setting up qPCR as well as the wide availability of qPCR equipment needed, this would be the most optimal assay for rapid, confirmatory, molecular diagnosis of ALA in the tertiary care laboratory setting in India, whereas further optimization of LAMP or antibody-based detection is required for use at smaller or secondary hospitals.

Amoebic liver abscess in an adult Nigerian: A case report

Background: Amoebic liver abscess (ALA) is a parasitic infection caused by Entamoeba histolytica. ALA is a significant health concern, particularly in regions with poor sanitation and hygiene practices. Radiological imaging plays a crucial role in the diagnosis and management of ALA. Methods: We present a case report of a 40-year-old male patient with ALA. The patient presented to a radio diagnostic centre in Umuahia with right upper quadrant abdominal pain, fever,diarrhea and weight loss. Radiological evaluation was performed using abdominal ultrasound and contrast-enhanced CT scan. The imaging findings were correlated with clinical presentation and laboratory investigations. Results: The radiological findings revealed a focal hypoechoic lesion in the right hepatic lobe with ill-defined margins and internal echoes suggestive of liquefaction. The contrast-enhanced CT scan confirmed the presence of a well-defined, hypodense lesion with peripheral enhancement and central hypoattenuation. No evidence of biliary ductal dilatation or vascular invasion was observed. Based on the findings, a diagnosis of ALA was made, and the patient was initiated on intravenous metronidazole therapy. Follow-up imaging demonstrated a decrease in abscess size and resolution of internal echoes, indicating a positive response to treatment. Conclusion: Radiological imaging, including ultrasound and CT scan, plays a pivotal role in the diagnosis and management of ALA. The characteristic imaging findings, such as hypoechoic lesions with internal echoes and peripheral enhancement with central hypoattenuation, aid in differentiating ALA from other hepatic lesions. Early diagnosis and prompt initiation of appropriate therapy are crucial for favorable patient outcomes. Radiological follow-up allows monitoring of treatment response and guides further management decisions.

Real-time loop-mediated isothermal amplification (real-time LAMP) assay for rapid diagnosis of amoebic liver abscess.

Among the parasitic diseases, amoebic liver abscess (ALA) ranks second to malaria in terms of mortality. Due to the poor sensitivity of conventional diagnostic methods, there is a need for the development of effective and rapid diagnostic methods for ALA. Thus, the purpose of this work was to develop a real-time loop-mediated isothermal amplification (RT-LAMP) assay specific to Entamoeba histolytica. Further, we compared the performance of real-time LAMP with conventional and real-time PCR (RT-PCR) targeting 18S small subunit ribosomal RNA (18S SSU rRNA) gene of E. histolytica in patients with ALA. A total of 126 liver samples were obtained for the study. Of these, 96 aspirated pus samples were obtained from patients suffering from an ALA (serology confirmed, anti-amoebic immunoglobulin IgG positive), 19 aspirated pus samples from patients with pyogenic liver abscess (PLA, 16S RNA gene positive) and 11 autopsy liver tissues. The results showed that the DNA of E. histolytica was detected in 81 samples by conventional PCR, 93 by RT-PCR and 95 by RT-LAMP. The analytical sensitivity of the RT-LAMP assay was much higher than the other two techniques. RT-LAMP assay was able to amplify up to one copy of the targeted gene of E. histolytica while conventional PCR and RT-PCR could amplify up to 103 and 102 copies of the targeted gene of E. histolytica, respectively. In conclusion, RT-LAMP proved to be a sensitive, specific and rapid test which can be utilised as an effective tool for the diagnosis of ALA.

Management of Amoebic Liver Abscess: A hospital based prospective observational study

Background: Approximately 400 million people worldwide are affected by amoebiasis and the most common extra-intestinal manifestation of this infection especially in developing countries is amoebic liver abscess. The protozoa Entamoeba histolytica, enters the portal venous system from the colon. Early and prompt diagnosis with immediate treatment leads to improved morbidity and mortality rates. Primary treatment of amoebic liver abscess is conservative, however in certain high risk cases for rupture, guided drainage or surgical exploration should not be delayed. Materials and methods: This was a hospital based prospective observational study conducted in the Department of Surgery, Hamdard Institute of Medical Sciences & Research, New Delhi. The study was conducted over a period of 02 years from March 2018 to March 2020. A total of 52 patients with diagnosis of amoebic liver abscess were included in the study. Follow up period was 06 months after discharge from the hospital. Data was analyzed and observed for various parameters including various modalities of management, morbidities and moralities. Results: A total of 52 patients (48 male and 04 female) were included in the study. A low prevalence of amoebic liver abscess was seen in the patients below 10 years of age. Majority of our patients belong to lower middle class (42.30%). Abdominal pain was the most common symptom reported (78.84%). Most commonly seen abnormalities in laboratory findings were deranged coagulation profile (71%), leukocytosis (65%), hypoalbuminemia (60%) and elevated alkaline phosphatase (52%). Right lobe was involved in 80 % patients and 94% patients had solitary abscess. Amoebic serology was positive in all patients. All patients were treated with Metronidazole 750mg (intravenous/oral) thrice daily for a period of 10-14 days. Out of 52 patients, 43 showed improvement after initial three days of therapy with metronidazole. Remaining 09 patients didn’t show improvement with metronidazole alone and hence were subjected to other treatment modalities. Conclusion: Amoebic Liver abscess is prevalent in developing countries particularly India owing to the poor sanitation and hygiene conditions. Most of the uncomplicated cases detected early can be managed medically while those developing complications may need intervention in the form of aspiration or pigtail insertions. Surgical exploration in the form of laparoscopy and laparotomy is reserved for selected cases of rupture and where ever possible laparoscopic drainage should be preferred. The key to preventing amoebic infections is mass sanitation awareness along with improving health education.

IgG Anti-Body Titers among Patients with Amoebic Liver Abscess in Bangui, Central African Republic

Entamoeba histolytica (Eh) is a protozoan parasite that causes amoebiasis characterized by intestinal damage and amoebic liver development and is an important cause of hospitalization in low-middle income countries. The aims of this study were to determine the prevalence and the titer of IgG anti Eh in ALA (Amoebic Liver Abscess) patients’ in Bangui according sex, age and other risk factors. This was a cross sectional study where data was collected between January 2018 and October 2020. The diagnosis of ALA was suspected based on clinical symptoms of; fever, abdominal pain (usually in the right hypochondrium or epigastrium) and clinical signs of hepatomegaly and/or tender liver with or without jaundice and abdominal ultra-sonography. ALA patients’ IgG antibody titers were measured by Indirect Hemmaglutination Assay and Chi-square test was used. A total of 1249 ALA patients were included, among whom 570 (45.64%) were positive. Of these, 244 (42.08%) had titer 1:160 or less, 223 patients’ (39.13%) had titer ranging from 1:320 to 1:640 and 103 patients (18.07%) had strong titer ranging from 1:1280 to 1:2560. The association between antibody titer results, age and sex was no significant (p = 1.0000). Our findings indicate a high prevalence of ALA and show no significant difference between the sex and age ALA patients.

The Consequence of COVID-19

SARS-CoV-2 is the third and largest pandemic that emerged in Wuhan city, Hubei province, China in 2019. As per WHO 45,988,595 people have been infected and the COVID 19 has caused more than 1,194,979 deaths. The clinical spectrum of COVID 19 varies from asymptomatic presentation to multi-organ dysfunction. The pathophysiology behind the sequel of COVID 19 immuno-suppression is an area yet to be explored. Here, we report a case of 52 year old male with persistent pyrexia post his recovery from COIVD-19. On further evaluation, a diagnosis of amoebic liver abscess that resulted as a sequel of COVID-19 was made.

Utility of loop-mediated isothermal amplification as a point-of-care test in diagnosis of amoebic liver abscess.

Definitive diagnosis of amoebic liver abscess is challenging owing to the unavailability of sensitive commercial point-of-care molecular tests. The primary aim of our prospective diagnostic study was to compare available laboratory methods for the diagnosis of Entamoeba histolytica in clinical samples with loop-mediated isothermal amplification. We compared deoxyribonucleic acid (DNA) analysis methods, namely, loop-mediated isothermal amplification and reverse transcriptase polymerase chain reaction and enzyme-linked immunosorbent assay (ELISA) using pus, stool and blood samples from 200 patients with clinical and radiological diagnosis of amoebic liver abscess. Loop-mediated isothermal amplification had significantly higher sensitivity (88%) as compared to reverse transcriptase polymerase chain reaction (64%) and excellent specificity (100%).

Evaluation of loop mediated isothermal amplification for the diagnosis of amoebic liver abscess

Evaluation of loop mediated isothermal amplification for the diagnosis of amoebic liver abscess

Evaluation of loop mediated isothermal amplification for the diagnosis of amoebic liver abscess

Evaluation of loop mediated isothermal amplification for the diagnosis of amoebic liver abscess

Comparison of nested-multiplex, Taqman & SYBR Green real-time PCR in diagnosis of amoebic liver abscess in a tertiary health care institute in India.

Background & objectives:Amoebiasis is a common parasitic infection caused by Entamoeba histolytica and amoebic liver abscess (ALA) is the most common extraintestinal manifestation of amoebiasis. The aim of this study was to standardise real-time PCR assays (Taqman and SYBR Green) to detect E. histolytica from liver abscess pus and stool samples and compare its results with nested-multiplex PCR.Methods:Liver abscess pus specimens were subjected to DNA extraction. The extracted DNA samples were subjected to amplification by nested-multiplex PCR, Taqman (18S rRNA) and SYBR Green real-time PCR (16S-like rRNA assays to detect E. histolytica/E. dispar/E. moshkovskii). The amplification products were further confirmed by DNA sequence analysis. Receiver operator characteristic (ROC) curve analysis was done for nested-multiplex and SYBR Green real-time PCR and the area under the curve was calculated for evaluating the accuracy of the tests to dignose ALA.Results:In all, 17, 19 and 25 liver abscess samples were positive for E. histolytica by nested-multiplex PCR, SYBR Green and Taqman real-time PCR assays, respectively. Significant differences in detection of E. histolytica were noted in the real-time PCR assays evaluated (P<0.0001). The nested-multiplex PCR, SYBR Green real-time PCR and Taqman real-time PCR evaluated showed a positivity rate of 34, 38 and 50 per cent, respectively. Based on ROC curve analysis (considering Taqman real-time PCR as the gold standard), it was observed that SYBR Green real-time PCR was better than conventional nested-multiplex PCR for the diagnosis of ALA.Interpretation & conclusions:Taqman real-time PCR targeting the 18S rRNA had the highest positivity rate evaluated in this study. Both nested multiplex and SYBR Green real-time PCR assays utilized were evaluated to give accurate results. Real-time PCR assays can be used as the gold standard in rapid and reliable diagnosis, and appropriate management of amoebiasis, replacing the conventional molecular methods.

Rapid diagnosis of amoebic liver abscess using recombinant Entamoeba histolytica pyruvate phosphate dikinase

IntroductionAmoebiasis, caused by the protozoan parasite Entamoeba histolytica, is an important parasitic cause of death in humans; and mortality is mainly due to amoebic liver abscess (ALA). Accurate and early diagnosis is thus important; however its diagnosis still poses many challenges due to the limitations of the available detection tools. Previously, we have reported that an excretory-secretory protein of E. histolytica, pyruvate phosphate dikinase (PPDK), is a potential diagnostic marker for ALA, hence it may be exploited in the development of a new test for ALA. ObjectiveTo develop lateral flow dipstick (LFD) test using recombinant PPDK (rPPDK) and evaluate its potential for diagnosis of ALA. MethodsrPPDK was expressed, purified and evaluated by Western blot. In parallel recombinant Gal/GaNAc lectin (rGal/GalNAc), as control antigen, was produced and tested similarly. The LFD test using rPPDK was subsequently developed (rPPDK-LFD) and evaluated for serodiagnosis of ALA. Results & DiscussionThe rPPDK protein expressed had an estimated molecular mass of 98 kDa as determined by SDS-PAGE, and purification using Ni-NTA resin yielded 1.5 mg of rPPDK from 1 L of culture. The protein identity was confirmed by MALDI-TOF/TOF. Western blots using sera from patients with ALA, healthy individuals and other diseases probed with antihuman IgG4-HRP showed the highest sensitivity (93.3%) and specificity (100%); as compared to blots using IgG and IgG1 as secondary antibodies. Additionally, rPPDK showed better specificity when compared to rGal/GalNAc. In the development of the LFD test, the optimum concentration of rPPDK and optical density of colloidal gold conjugated anti-human IgG4 were 1.25 mg/ml and 5, respectively. Evaluation of rPPDK-LFD using ALA patients and control serum samples showed 87% diagnostic sensitivity and 100% specificity. ConclusionThe laboratory prototype rPPDK-LFD showed good potential for rapid diagnosis of ALA, and merit further multicentre validation using larger number of serum samples.

Evaluation of antigen detection and polymerase chain reaction for diagnosis of amoebic liver abscess in patients on anti-amoebic treatment.

BackgroundDiagnosis of amoebic liver abscess (ALA) in patients on anti-amoebic drugs is difficult. There is scanty data on this issue using Entamoeba histolytica (E. histolytica) lectin antigen and polymerase chain reaction (PCR). We studied utility of lectin antigen, PCR, and IgG antibody in diagnosis of liver abscess in patients on anti-amoebic treatment. Liver aspirate of 200 patients, of which 170 had anti-amoebic drug prior to drainage, was tested for E. histolytica lectin antigen by (ELISA), PCR, bacterial culture, and serum IgG antibody by (ELISA). Classification of abscesses was based on result of anti-amoebic IgG antibody and bacterial culture, E. histolytica PCR and bacterial culture, and E. histolytica lectin antigen and bacterial culture.FindingsUsing anti-amoebic IgG antibody and bacterial culture, 136/200 (68.0%) were classified as ALA, 12/200 (6.0%) as pyogenic liver abscess (PLA), 29/200 (14.5%) as mixed infection, and 23/200 (11.5%) remained unclassified. Using amoebic PCR and bacterial culture 151/200 (75.5%) were classified as ALA, 25/200 (12.5%) as PLA, 16/200 (8.0%) as mixed infection, and 8/200 (4.0%) remained unclassified. With E. histolytica lectin antigen and bacterial culture, 22/200 (11.0%) patients were classified as ALA, 39/200 (19.5%) as PLA, 2/200 (1.0%) as mixed infection, and 137/200 (68.5%) remained unclassified.ConclusionsE. histolytica lectin antigen was not suitable for classification of ALA patients who had prior anti-amoebic treatment. However, PCR may be used as alternative test to anti-amoebic antibody in diagnosis of ALA.

Amoebic Liver Abscess: An Appraisal

Amoebic Liver Abscess: An Appraisal

Analysis of Entamoeba histolytica Excretory-Secretory Antigen and Identification of a New Potential Diagnostic Marker

Serodiagnosis of amoebiasis remains the preferred method for diagnosis of amoebic liver abscess (ALA). However, the commercially available kits are problematic in areas of endemicity due to the persistently high background antibody titers. Human serum samples (n = 38) from patients with ALA who live in areas of endemicity were collected from Hospital Universiti Sains Malaysia during the period of 2008 to 2010. Western blots using excretory-secretory antigen (ESA) collected from axenically grown Entamoeba histolytica were probed with the above serum samples. Seven antigenic proteins of ESA with various reactivities were identified, i.e., 152 kDa, 131 kDa, 123 kDa, 110 kDa, 100 kDa, 82 kDa, and 76 kDa. However, only the 152-kDa and 110-kDa proteins showed sensitivities above 80% in the Western blot analysis. All the antigenic proteins showed undetectable cross-reactivity when probed with healthy human serum samples (n = 30) and serum samples from other infections (n = 33). From the matrix-assisted laser desorption ionization-two-stage time of flight (MALDI-TOF/TOF) analysis, the proteins were identified as heavy subunits of E. histolytica lectin and E. histolytica pyruvate phosphate dikinase, respectively. Use of the E. histolytica lectin for diagnosis of ALA has been well reported by researchers and is being used in commercialized kits. However, this is the first report on the potential use of pyruvate phosphate dikinase for diagnosis of ALA; thus, this molecule merits further evaluation on its diagnostic value using a larger panel of serum samples.

Evaluation of small-subunit rRNA touchdown polymerase chain reaction for direct detection of Entamoeba histolytica in human pus samples from patients with amoebic liver abscess

Purpose: The aim of the present study was to evaluate the use of touchdown polymerase chain reaction (TD-PCR) for the detection of Entamoeba histolytica in liver pus samples obtained from patients with a clinical diagnosis of amoebic liver abscess (ALA) using small-subunit rRNA (SSU rRNA) as the target gene. Materials and Methods: Microscopic examination in vitro culture and serological test for the detection of E. histolytica in 67 pus samples obtained from ALA patients was performed. Molecular studies were carried out by both conventional PCR and TD-PCR targeting the SSU rRNA gene using the same sets of primers and the results were compared. Results: TD-PCR detected the presence of E. histolytica in 86.5% of the liver pus samples within 2.5 h as compared with 82.08% by conventional PCR within 3.5– 4 h. Conclusion: TD-PCR assay may serve as a relatively better detection method for E. histolytica over conventional PCR with respect to the turnaround time, increased sensitivity, specificity and yield.

P0027 DOCTOR, I HEAR HISSING SOUNDS COMING FROM MY CHEST!?

quadrant. It was such a diffuse tenderness and guardness which extends to the right lower intercostal spaces. He spiked temperature only at nights. He had raised white blood cells count and ESR. No focus of infection was found initially however a CT scan (figure 1) showed a rounded well defined mass between the left and right lobe and very superficial. The possible diagnoses were an amoebic liver abscess or a hydatid cyst. Stool examinations did not show ova, cyst or parasite. Serological tests showed positive Amoebic IFAT (Indirect Immunofluorescent Antibody Test) and a negative Hydatid ELISA test (Enzyme Linked ImmunoSorbent Assay). These findings suggested the diagnosis of Amoebic liver abscess. The patient was started on oral metronidazole 800 mg tds and oral cefalexin 500 mg tds for a total of 10 days. A letter was sent to his GP to start him on Diloxanide 500 mg tds for 10 days. Learning points: • To be aware of amoebic liver disease especially in overseas patients. • Amoebic liver abscess does not always follow Amoebic dysentery. • Current trend is to treat Amoebic liver abscess medically not drainage unless it is very big or not responding to medical treatment. • Your treatment should include luminal amoebicide (Diloxanide) after a course of tissue amoebicide (Metronidazole). • CT scan showed a rounded well defined mass between the left and right lobe which is typical for Amoebic liver Abcess

Missed diagnosis of amoebic liver abscess: a case for forward clinical reasoning

Increasingly, a wrong diagnosis is made and wrong investigations and treatment ordered, because the doctor uses one or two symptoms to jump into a premature conclusion, without consideration of the totality of a patient's presentation. This is not forward clinical reasoning. Forward clinical reasoning is based on a systematic approach to patient's problems. The objective of this paper is to use a real case to illustrate the pitfall in ignoring forward clinical reasoning and how forward clinical reasoning serves the physician's and patient's interest better. The case of a 3 year old who had amoebic liver abscess but was wrongly diagnosed and treated for lobar Pneumonia with pleural effusion is highlighted. The sequence for forward clinical reasoning is used to show how the right diagnosis could have been arrived at. The correct diagnosis following sequential forward clinical reasoning saves time, money and life.

Enfoque clínico y diagnóstico del absceso hepático

The non invasive diagnosis of amebic liver abscess allows the use of empirical therapy without the requirement of invasive diagnostic procedures. To determine the discriminatory capacity of clinical, laboratory and ultrasound studies for the etiological diagnosis of liver abscess. Sixty one patients were initially included in this prospective study, but 12 did not comply with the inclusion criteria. Of the rest, 29 (59%) had an amebic liver abscess, 16 (33%) had a pyogenic liver abscess and four (8%) had an abscess of mixed etiology. Blood cultures were done in 42 patients. Ultrasound guided needle aspiration was done in 7 patients with amebic liver abscess and 13 patients with non amebic liver abscess. The clinical picture and ultrasound findings were similar in all types of amebic abscess. ELISA test for IgG anti-Entamoeba histolytica antibodies were positive in 100% of patients with amebic liver abscess. Antibodies measured by gel diffusion were positive in 93%. All patients with mixed liver abscess had positive antibodies and some of them positive culture. Blood cultures were positive for anaerobic bacteria in five patients. Cultures of aspirated material were positive in 7 patients (obligate anaerobic bacteria in 3 and facultative anaerobic bacteria in the rest). The most common complications, whatever the etiology, were right pleural effusion and systemic inflammatory response. A final model of binomial regression analysis revealed that age under 40 years, an hematocrit greater than 35% and an elevation in prothrombin time of less than 1.5 seconds had enough discriminatory capacity for the diagnosis of amoebic liver abscess.

Prevention and Treatment Strategies in Giardiasis and Amoebiasis

In intestinal amoebiasis, motile Entamoeba histolytica trophozoites with ingested erythrocytes should be identifiable in stool or mucosal scrapings. Finding E. histolytica cysts is not sufficient for the diagnosis. The diagnosis of amoebic liver abscess is confirmed by finding an abscess by imaging study and an elevated serum antibody titre to the causative organism. Treatment for both forms of the disease is a nitroimidazole for trophozoites and a lumenal drug directed at the cysts.

Standardization and evaluation of ELISA for the serodiagnosis of amoebic liver abscess.

An ELISA test for the serological diagnosis of amoebic liver abscess (ALA) was standardized and evaluated in sera from three groups of patients: (1) three patients with diagnosis confirmed by isolation of the parasite, (2) thirty seven patients with diagnosis established by clinical findings and ultrasound studies and (3) seven patients whose diagnosis were established by clinical findings and a positive double immunodifusion test. Ninety one serum samples from healthy subjects and 22 from patients with other liver or parasitic diseases were also included in the study. The optimum concentration of Entamoeba histolytica antigen was 1.25 micrograms/ml and optimum dilutions of serum and anti-human IgG -alkaline phosphatase conjugate were 1:400 and 1:4000 respectively. The cut-off point of the ELISA test in this study was an absorbance value of 0.34. The test parameters were: sensitivity = 95.7%, specificity = 100%, positive predictive value = 100% and negative predictive value = 98.2%. The ELISA test was found to be of great use as a diagnostic tool for the establishment of amoebic etiology in patients with clinical supposition of ALA. The test could also be used for seroepidemiological surveys of the prevalence of invasive amoebiasis in a given population, since it allows the processing of a greater number of samples at a lower cost than other serological tests.