Evaluating the efficacy of nitazoxanide in uncomplicated amebic liver abscess

BACKGROUND

Amebic liver abscess is treated successfully with metronidazole or another nitroimidazole drug followed by a luminal amebicide. Metronidazole has long been preferred, but has been associated with several adverse effects including intolerance in certain clinical situations. Mechanisms of metronidazole resistance and mutagenic potential have been described. Effects of the use of drug in pregnant women and infants of lactating women are unknown. Nitazoxanide was proven to be efficacious in treating invasive intestinal amebiasis. Therefore, the present study was undertaken to assess the efficacy and safety of nitazoxanide as compared to metronidazole in patients with uncomplicated amebic liver abscess.

METHODS

Patients with clinical and ultrasonography features suggestive of liver abscess, positive amebic serology, and/or anchovy sauce appearance on aspiration of the pus were included in the study and randomized into two parallel treatment groups. Group M received metronidazole, 2-2.5 g/day intravenous (IV), for inpatients, or 2-2.4 g/day oral, for outpatients in three divided doses for 14 days. Group N received nitazoxanide 500 mg BD per oral for 10 days.

RESULTS

A total of sixty subjects fulfilling the inclusion criteria were randomized equally into two groups, group M and group N. Number of patients achieving symptomatic clinical response (SCR) was similar in the two groups (80% vs. 76.7%, p = 1.00), though time to achieve symptomatic clinical response was significantly lower in metronidazole group as compared to that in nitazoxanide group. Greater proportion of patients achieved early clinical response (ECR) in metronidazole group as compared to nitazoxanide group. Complete resolution of abscess, at 6 months, was noted in 18 (60%) patients in the M group and 22 (73.3%) patients in the N group (p = 0.273). Metronidazole was associated with significantly greater frequency of adverse effects than nitazoxanide.

CONCLUSIONS

This study shows equivalent efficacy of nitazoxanide in uncomplicated amebic liver abscess as compared to metronidazole, with better tolerability and advantage of simultaneous luminal clearance, thus reducing chances of recurrence.

TRIAL REGISTRATION

CTRI/2019/01/017249.

Huge Amoebic Liver Abscess in the Left Lobe Treated by Oral Administration of Metronidazole

A man in his 60s visited a clinic with chief complaints of a fever and general malaise. Suspecting a liver abscess in the left lobe with infiltration into the subcutaneous fat tissue under the rectus abdominis muscle based on computed tomography findings, we performed fine-needle aspiration. An amoebic liver abscess was diagnosed. Remission was achieved by the oral administration of metronidazole alone without placement of a drainage tube. The results obtained in this case suggest that the first line of treatment should be a non-invasive approach with oral administration alone. Invasive intervention should then be considered depending on subsequent progress.

[Infection or metastases? The amoebic abscess]

BACKGROUND

Cases of Entamoeba histolytica infections in the Netherlands are usually imported diseases. The most common extra-intestinal manifestation of E. histolytica is the amoebic abscess. Patients can present with a clinical picture of colitis with pain in the upper right abdomen, accompanied by fever in cases of liver abscess. Diagnostics focus mainly on the detection of E. histolytica with PCR or ELISA. Infections are treated with metronidazole, with clioquinol as follow-up treatment.

CASE DESCRIPTION

A 61-year-old, previously healthy man was admitted to hospital with pain in the upper right abdomen and fever. He had no history of travel in the tropics or sub-tropics. CT imaging revealed liver abscesses or liver metastases. Cultures of abscess fluid were negative. After extensive diagnostics the patient was shown to have an amoebic abscess for which he was successfully treated.

CONCLUSION

If the bacterial cultures of liver abscess fluid continue to be negative the possibility of an amoebic abscess should be considered, even with a negative history of travel to the tropics or subtropics.

Learning points from a case of severe amoebic colitis

A case of amoebic colitis and liver abscess is described in a previously fit 59-year old man who had been given the incorrect diagnosis of ulcerative colitis. His symptoms were so severe that a colectomy was being considered. The patient had a significant travel history including trips to Morocco, the Gambia and Cape Verde, putting him at risk of acquiring amoebic disease. However, this history was not ascertained until much later on in the disease process. The case highlighted crucial learning points including the importance of taking a lifelong travel history, the difficulties in telling ulcerative colitis and amoebic colitis apart both clinically and histopathologically, and the importance of sending multiple stool samples for parasitological microscopy analysis in patients being investigated for inflammatory bowel disease.

Multiple Medium Amoebic Liver Abscesses Successfully Treated with Medication and Comprehensive Percutaneous Catheter Drainage

Solitary small (<5 cm) amoebic liver abscesses in the right lobe are generally treated using medication alone, while large abscesses are typically treated via a combination of medication and drainage. However, the therapeutic indications for multiple medium (5-10 cm) amoebic liver abscesses remain unclear. We herein report the findings of a 53-year-old woman who was receiving lenalidomide for multiple myeloma and subsequently developed multiple amoebic abscesses. Metronidazole alone was unsuccessful, although metronidazole and repeated percutaneous catheter drainage of the right lobe, left lobe, and thorax proved to ultimately be successful. Therefore, the successful use of medication alone may be associated with the total combined abscess volume.

Common presentation of amebic liver abscess - a study in a tertiary care hospital in Bangladesh

Amebic liver abscess is a tropical disease. It is not uncommon in Bangladesh. Given the often nonspecific nature of complains related to amebic liver abscess, this study was carried out to identify the most common presentation. This hospital based cross sectional study was carried out in 30 cases of amebic liver abscess in the Department of Medicine, Gastroenterology and Hepatology, Comilla Medical College Hospital, Bangladesh. Clinical and laboratory informations were recorded including symptoms, signs, location and number of abscess. Among 30 patients, 27 were male (90%) and 3 female (10%), mean age of male and female were 42±11 and 52±8 respectively. Common clinical symptoms were fever (93%) and abdominal pain (93%). Common signs were right upper quadrant tenderness (60%), hepatomegaly (67%). Most of the patient had single abscess (80%) and location of abscess was predominantly in the right lobe (77%). Radiological abnormality on x-ray chest was present in 30% cases. Common clinical presentation of amebic liver abscess patients were fever and right upper abdominal pain. Duration of symptoms was more than two weeks in most cases.

Unusual multiple large abscesses of the liver: interest of the radiological features and the real-time PCR to distinguish between bacterial and amebic etiologies

We report a rare case of amebiasis generating 19 large liver abscesses. Such a quantity of abscesses is rare, especially when occurring in a young casual traveler without any immunodeficiency disorders. A possible co-infection was excluded. By contrast, the amebic etiology was confirmed by means of serology and real-time PCR.

Residual amoebic liver abscess in a prospective renal transplant recipient

Amoebic liver abscess (ALA) is by far the most common extraintestinal manifestation of invasive amoebiasis. The vast majority of these resolve with treatment; however, a small percentage of the treated ALAs are known to persist asymptomatically. Herein, we present a prospective renal allograft recipient with a residual liver abscess who had a successful renal transplant after treatment. In our opinion, persistence of a radiological finding of residual abscess in the absence of clinical disease does not appear to be a contraindication to renal transplantation.

[A case of amoebic liver abscess complicated by a gastric fistula cured with oral medication only]

A 26-year-old man was admitted to our hospital because of a high-grade fever and abdominal pain. A blood test showed marked inflammation. Enhanced computed tomography (CT) showed an 8.0×6.0cm cystic lesion in the left hepatic lobe. Esophagogastroduodenoscopy showed a huge egg-yolk-like mass in the gastric submucosa in the lesser curvature of the gastric body from the gastric angle. There were 3 ulcers on the mass, out of which milky pus flowed. Trophozoites of Entamoeba histolytica were detected from cultures of the liver abscess and a biopsy of the gastric ulcers. The amoebic dysentery antibody titer was increased 1600 times. An amoebic liver abscess complicated by a gastric fistula was diagnosed. As therapy, oral metronidazole was administered for 2 weeks without percutaneous drainage. The systemic inflammatory findings improved immediately and the abscess decreased markedly in size.

[Multinodular hepatopathy with fever in a tropical climate: hepatic amebiasis with multiple abscesses]

Hepatic amebiasis is common in tropical zones. Solitary abscess is the classical form but multinodular presentation does not rule out amebiasis as the underlying cause. Definitive diagnosis cannot be based on clinical and radiologic findings alone. Serological testing for amebiasis is necessary. In zones where serology is unavailable, response to presumptive metronidazole treatment is still a useful for diagnosis.

[Pleuro-pulmonary manifestations disclosing hepatic amoebiasis]

During a mission in ex-Yugoslavia between 2001 and 2004, three French soldiers were sent home because of right pneumopathy, right pleurisy after appendicectomy, haemoptysis and liver haematoma, respectively. They previously were stationed in Africa and/or South America. The initial diagnosis was quickly modified: pleuropulmonary manifestations of amoebic hepatic abscess in two cases, and pleuropulmonary amoebiasis in the last case. The outcome was favourable with standard anti-amoebic treatment. The reports illustrate the possibility of hepatic amoebiasis with local pleuropulmonary manifestations and an exceptional case of pleuropulmonary amoebiasis with hepatobronchial fistula. The authors report this experience because it demonstrates that amoebiasis in European countries remains an often forgotten diagnosis. Although known for a long time in developing countries, amoebiasis in the military or in tourists should be systematically considered.

Image-guided percutaneous procedure plus metronidazole versus metronidazole alone for uncomplicated amoebic liver abscess

BACKGROUND

Metronidazole is the standard of care for uncomplicated amoebic liver abscesses (considering that complicated liver abscesses are those localized in left lobe, multiple, and/or pyogenic abscesses). However, a subset of patients with amoebic liver abscesses remain symptomatic, with a significant risk of rupture of the abscess into the peritoneum. The role of image-guided percutaneous therapeutic aspiration in these patients remains controversial.

OBJECTIVES

To assess the beneficial and harmful effects of image-guided percutaneous procedure plus metronidazole versus metronidazole alone in patients with uncomplicated amoebic liver abscess.

SEARCH STRATEGY

We searched the Cochrane Hepato-Biliary Group Controlled Trials Register, the Cochrane Central Register of Controlled Trials in The Cochrane Library (Issue 2, 2007), MEDLINE (1966 to November 2007), EMBASE (1988 to September 2007), and Science Citation Index Expanded (1945 to September 2007).

SELECTION CRITERIA

Randomised or quasi-randomised trials comparing an image-guided percutaneous procedure plus metronidazole versus metronidazole alone in patients with uncomplicated amoebic liver abscess.

DATA COLLECTION AND ANALYSIS

Inclusion criteria, trial quality assessment, and data extraction were done in duplicate. We calculated relative risks (RR) and mean differences, and checked for heterogeneity by visual inspection of forest plots and chi-squared and I(2) tests.

MAIN RESULTS

Seven low quality randomised trials were included. All studies included a total of 310 patients, but due to selective outcome reporting bias, less patients could be included in our analyses. Pooled analysis of three homogenous trials showed that needle aspiration did not significantly increase the proportion of patients with fever resolution (RR 0.60, 95% confidence interval (CI) 0.22 to 1.61). Sensitivity analysis according to trial quality preserved these findings. Trials that evaluated resolution of abdominal pain, days to resolution of fever, pain, resolution of abscess cavities, reduction in liver size, and duration of hospitalisation were heterogeneous. The benefits in the number of days to resolution of pain (MD -1.59, 95%CI -2.73 to -0.42), number of days to resolution of abdominal tenderness (MD -1.70, 95%CI -2.86 to -0.54), and duration of hospitalisation (MD -1.31, 95%CI -2.05 to -0.57) were observed in the needle aspiration group only.

AUTHORS' CONCLUSIONS

Therapeutic aspiration in addition to metronidazole to hasten clinical or radiologic resolution of uncomplicated amoebic liver abscesses cannot be supported or refuted by the present evidence. The trials lack methodological rigour and adequate sample size to conclude on the presence of effectiveness of adjunctive image-guided aspiration plus metronidazole versus metronidazole alone. Further randomised trials are necessary.

Comparison of clinical characteristics of amebic liver abscess in human immunodeficiency virus (HIV)-infected and non-HIV-infected patients

BACKGROUND AND PURPOSE

Amebic liver abscess is an emerging parasitic disease in human immunodeficiency virus (HIV)-infected patients. Clinical characteristics of this disease have rarely been compared between patients with and without HIV infection.

METHODS

This retrospective study included 24 patients who had been diagnosed with amebic liver abscess during a 17-year period. The demographics, clinical manifestations, radiographic findings, and outcomes were compared between HIV-infected and non-HIV-infected patients.

RESULTS

Among 24 patients with amebic abscess, 8 were HIV-infected and 16 were non-HIV-infected. The mean (+/- standard deviation [SD]) age of HIV-infected patients was 41.0 +/- 11.3 years (range, 27-62 years), which was younger than that of the non-HIV-infected group (58.5 +/- 14.6 years; range, 27-77 years; p=0.01). Compared with non-HIV-infected controls, patients with HIV infection had lower white blood cell counts (median, 17.2 x 10(9)/L vs 10.4 x 10(9)/L; p=0.01), neutrophil/lymphocyte (N/L) ratio (median, 12.1 vs 2.7; p<0.01), total bilirubin (median, 42.7 micromol/L vs 13.7 micromol/L; p=0.02), blood urea nitrogen (median, 7.9 mmol/L vs 4.1 mmol/L; p=0.04), and creatinine (median, 114.9 micromol/L vs 88.4 micromol/L; p<0.01). On multivariate analysis, low N/L ratio remained a significant predictor for HIV infection (odds ratio, 0.49; 95% confidence interval, 0.264-0.912; p=0.024). No significant differences were observed in clinical manifestations, radiographic findings, and indirect hemagglutination titer between the 2 groups.

CONCLUSION

HIV-infected patients with amebic liver abscess tended to have a lower N/L ratio than non-HIV-infected comparators.

Detection of Entamoeba histolytica DNA in the saliva of amoebic liver abscess patients who received prior treatment with metronidazole

Saliva is an easily-accessible and a non-invasive clinical specimen alternate to blood and liver pus. An attempt was made to detect Entamoeba histolytica DNA released in the saliva of amoebic liver abscess (ALA) patients by applying 16S-like rRNA gene-based nested multiplex polymerase chain reaction (NM-PCR). The NM-PCR detected E. histolytica DNA in the saliva of eight (28.6%) of 28 ALA patients. The NM-PCR result was negative for E. histolytica DNA in the saliva of all the eight ALA patients who were tested prior to treatment with metronidazole but was positive in the saliva of eight (40%) of 20 ALA patient who were tested after therapy with metronidazole. The NM-PCR detected E. histolytica DNA in liver abscess pus of all 28 (100%) patients with ALA. The TechLab E. histolytica II enzyme-linked immunosorbent assay was positive for E. histolytica Gal/GalNAc lectin antigen in the liver abscess pus of 13 (46.4%) of the 28 ALA patients. The indirect haemagglutination (IHA) test was positive for anti-amoebic antibodies in the serum of 22 (78.6%) of the 28 ALA patients and 2 (5.7%) of 35 healthy controls. The present study, for the first time, demonstrates the release of E. histolytica DNA in the saliva of ALA patients by applying NM-PCR.

A study on the usefulness of Techlab Entamoeba histolytica II antigen detection ELISA in the diagnosis of amoebic liver abscess (ALA) at Hospital Universiti Sains Malaysia (HUSM), Kelantan, Malaysia

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.

Invasive amebiasis: an update on diagnosis and management

In its invasive form, the trophozoite is responsible for clinical syndromes, ranging from classical dysentery to extraintestinal disease with emphasis on hepatic amebiasis. Abdominal pain, tenderness and diarrhea of watery stool, sometimes with blood, are the predominant symptoms of amebic colitis. Besides the microscopic identification of Entamoeba histolytica, diagnosis should be based on the detection of specific antigens in the stool or PCR associated with the occult blood in the stool. Amebic dysentery is treated with metronidazole, followed by a luminal amebicide. The trophozoite reaches the liver causing hepatic amebiasis. Right upper quadrant pain, fever and hepatomegaly are the predominant symptoms. The diagnosis is made by the finding of E. histolytica in the hepatic fluid, or in the necrotic material at the edge of the lesion in a minority of patients, and by detection of antigens or DNA. Ultrasonography is the initial imaging procedure indicated. The local perforation of hepatic lesion leads to important and serious complications.

[Probable amebic brain abscess in a homosexual man with an Entamoeba histolytica liver abscess]

A 51-year-old Japanese-Brazilian homosexual man was admitted to a hospital because of fever, headache and right epigastralgia. He had been homosexual for 20 years. An abdominal CT revealed a liver abscess and microscopic examination of the pus of the drainage revealed cystic forms of Entamoeba histolytica. Oral administration of metronidazole 2,250 mg/day was started for amebic liver abscess. He complained of severe throbbing headache, and magnetic resonance imaging (MRI) of the brain showed a brain mass of approximately 2 cm in diameter in the right parietooccipital lobe. An amebic brain abscess was suspected and he was transferred to our hospital. Continuous oral administration of metronidazole for 49 days instead of invasive procedures gradually improved headache, fever and right epigastralgia. On the follow-up MRIs, the brain mass was gradually encapsulated, reduced its size, and finally disappeared. A diagnosis of amebic brain abscess was made on the basis of coexistent amebic liver abscess, MRI findings and a dramatic effectiveness to metronidazole. One should pay attention to E. Histolytica infection in the differential diagnosis of the abscess of the liver and brain since it has been increasing in Japan in recent years.

Late experimental amebic liver abscess in hamster is inhibited by cyclosporine and N-acetylcysteine

During early experimental amebic liver abscess in hamsters (EALAH), acute inflammation is primarily responsible for tissue damage. However, during the late stages of this process, the relative contribution to tissue destruction of both parasite factors and host response is unknown. In the present work, the role of the cellular immune response in tissue damage during EALAH is explored by using the immunosuppressor drug cyclosporine A (CsA). CsA treatment inhibits tissue damage after 72 h (but not at 24 h). Also, many well-preserved parasite clusters with minimal or no leukocyte influx and with minimal or no tissue destruction characterize the late stage of the process (7 days). The same results are observed with the immunosuppressor tacrolimus, but not with sirolimus; the latter drug does not cause immunosuppression in hamsters. On the other hand, similar results are observed with the antioxidant and anti-inflammatory N-acetylcysteine, with minimal immunosuppression in hamsters. These results suggest that, as in the early EALAH (24 h), during the late stages of the process (7 days), inflammation is also primarily responsible for tissue damage. However, lysosomal and cationic proteins are responsible for the early lesions, whereas reactive oxygen and nitrogen species are primarily involved in late stages.

Amebic liver abscess: report of three cases

Amebic abscess is a common manifestation of extraintestinal amebiasis and it is associated with relatively high morbidity and mortality. We present three cases seen in Bari, Southern Italy, one of which was autochthonous and the other two were not. Diagnosis was performed by elevated antibody titre for E. histolytica through immunofluorescence assay and positive antigen determination by ELISA in stools and in abscess aspirate. Fever often accompanied by chills, abdominal pain, weight loss and hepatomegaly were present. Laboratory findings also revealed leukocytosis with neutrophilia. Pleural effusion was observed in two patients. In all our patients multiple abscesses were observed. All the patients were treated with metronidazole and two of them also underwent the aspiration of the amoebic abscess. In all of them there was improvement of the clinical picture, as demonstrated by computerized tomography.

Detection of excretory Entamoeba histolytica DNA in the urine, and detection of E. histolytica DNA and lectin antigen in the liver abscess pus for the diagnosis of amoebic liver abscess

BACKGROUND

Amoebic liver abscess (ALA) and pyogenic liver abscesses (PLA) appear identical by ultrasound and other imaging techniques. Collection of blood or liver abscess pus for diagnosis of liver abscesses is an invasive procedure, and the procedure requires technical expertise and disposable syringes. Collection of urine is a noninvasive procedure. Therefore, there has been much interest shown towards the use of urine as an alternative clinical specimen for the diagnosis of some parasitic infections. Here, we report for the first time the detection of E. histolytica DNA excreted in the urine for diagnosis of the cases of ALA.

RESULTS

E. histolytica DNA was detected in liver abscess pus specimen of 80.4% of ALA patients by a nested multiplex polymerase chain reaction (PCR) targeting 16S-like r RNA gene. The nested PCR detected E. histolytica DNA in all 37 (100%) liver abscess pus specimens collected prior to metronidazole treatment, but were detected in only 53 of 75 (70.6%) pus specimens collected after therapy with metronidazole. Similarly, the PCR detected E. histolytica DNA in 21 of 53 (39.6%) urine specimens of ALA patients. The test detected E. histolytica DNA in only 4 of 23 (17.4%) urine specimens collected prior to metronidazole treatment, but were detected in 17 of 30 (56.7%) urine specimens collected after treatment with metronidazole. The enzyme-linked immunosorbent assay (ELISA) for the detection of lectin E. histolytica antigen in the liver abscess pus showed a sensitivity of 50% and the indirect haemagglutination (IHA) test for detection of amoebic antibodies in the serum showed a sensitivity of 76.8% for the diagnosis of the ALA.

CONCLUSION

The present study for the first time shows that the kidney barrier in ALA patients is permeable to E. histolytica DNA molecule resulting in excretion of E. histolytica DNA in urine which can be detected by PCR. The study also shows that the PCR for detection of E. histolytica DNA in urine of patients with ALA can also be used as a prognostic marker to assess the course of the diseases following therapy by metronidazole. The detection of E. histolytica DNA in urine specimen of ALA patients provides a new approach for the diagnosis of ALA.

Randomized, single-blind, placebo-controlled multicenter trial to compare the efficacy and safety of metronidazole and satranidazole in patients with amebic liver abscess

The aims of our randomized, single-blind trial involving 49 patients were to study the efficacy, side effects, and tolerance of metronidazole and satranidazole in patients of amebic liver abscess. Twenty-five patients received metronidazole (800 mg TID) and 24 received satranidazole (300 mg TID with placebo at mealtime). Patients recorded side effects and tolerability through a performa. The time taken for resolution of fever and pain and the fall in abscess size was not significant. However, tolerance of satranidazole as reported by the patients was significantly better than metronidazole (P < .005). The incidence of adverse effects was significantly lower in the group given satranidazole (P < .005). The incidence of nausea and metallic taste was significantly lower in the patients given satranidazole (P < .005). Thus, despite having a similar efficacy, satranidazole showed a far lower incidence of side effects and had a significantly better tolerance than Metronidazole.

Amoebic hepatic abscesses in an HIV-positive patient

Herein we report the case of hepatic amoebic abscesses in an HIV-positive Italian seaman with a history of promiscuous heterosexual intercourse. In October 2004, the patient was hospitalized because of fever and recurring abdominal pain. Abdominal ultrasonography revealed six hepatic hypoechoid oval lesions with hyperechoid margins. Stool samples were negative for parasites and bacteria, and serology for Entamoeba histolytica was also negative. Therapy with meropenem plus levofloxacin was initiated. After a partial resolution of clinical symptoms and reduction of three hepatic lesions, the patient was again hospitalized in December 2004, because of recurring intense pain at the right hypochondrium and fever. At this time, one hepatic lesion at the sixth segment was enlarged, two lesions were unchanged, and the remaining three smaller abscesses were resolved. Serum antibodies for E. histolytica and amoebic antigens on the largest abscess drainage were positive; moreover, E. histolytica was also identified on drainage fluid with polymerase chain reaction (PCR). Therapy with metronidazole followed by paromomycin improved both symptoms and radiographic images. This case report suggests that in HIV-infected patients, invasive amoebiasis should be considered and atypical aspects, such as multiple hepatic lesions, delayed positivity of serology for E. histolytica, and possible bacterial superinfection should be evaluated.

Ultrasound patterns and frequency of focal liver lesions after successful treatment of amoebic liver abscess

OBJECTIVE

To evaluate the frequency and morphology of residual liver lesions in patients successfully treated for amoebic liver abscess.

METHODS

Retrospective ultrasound-based study of 240 adult males from an amoebiasis-endemic area in Vietnam with a documented clinical history of amoebic liver abscess. Subjects were re-examined by hepatic ultrasound 1-13 years after abscess treatment.

RESULTS

In 17 subjects (7.1%) focal hypo- or isoechoic areas were identified within the liver with a diameter of 8-48 mm surrounded by a hyperechoic wall. These lesions were associated with positive amoeba serology, were located at the site of the previous abscess and their sonographic appearances corresponded to post-amoebic liver abscess residues. Residues were found in all groups of patients irrespectively of the time-span since the abscess was treated. However, lesions older than 7 years showed some degree of calcification. Otherwise, lesions were apparently inactive, as patients had no clinical symptoms or signs of inflammation and follow-up after one year revealed no changes in size or pattern.

CONCLUSION

The vast majority of amoebic liver abscesses resolve to a sonographically normal parenchymal pattern. However, in a small proportion of cases characteristic residues remain. These residues do not require further treatment or diagnostic intervention and should be considered in the differential diagnosis of space-occupying liver lesions, in particular in patients from amoebiasis-endemic areas.

[Amoebic infections of the lung and pleura]

INTRODUCTION

Pleuropulmonary involvement is the second most common extra-intestinal manifestation of entamoeba histolytica infection after liver abscess.

CASE REPORT

We report 2 cases of pleuropulmonary disease occurring in two men aged 32 and 48 years following an episode of dysentery. Purulent pleural infection was noted in one case. In the other both lung and liver abscesses occurred.

CONCLUSION

The diagnosis was confirmed by strongly positive serology in both cases. Treatment with metronidazole (1.5 g per day) for 15 days combined with pleural drainage led to a satisfactory outcome in both cases.

Cardiac tamponade due to intrapericardial rupture of an amebic liver abscess

Pericardial abscess is rare in healthy individuals, especially the amebic type. We report a case of pericardial abscess and cardiac tamponade due to intrapericardial rupture of an amebic liver abscess. A 31-year old Japanese male complained of fever to a local hospital. A liver mass was discovered in his left hepatic lobe by an abdominal echogram. He was referred to the internal department of our hospital and was treated with quinolone antibiotics. Two weeks after medication, he suddenly complained of epigastralgia and severe orthopnea and was admitted. Abdominal computed tomographic scan showed an enlarged liver mass, and massive pericardial effusion suggested cardiac tamponade. He underwent an emergency subxiphoid partial pericardiectomy under local anesthesia. 1,000 ml of light brownish fluid was removed and his condition improved. Although no ameba was cultivated from the pus, the amebic serological test was positive. Metronidazole was administered and the patient was discharged 31 days after surgery.

Protective activity of picroliv on hepatic amoebiasis associated with carbon tetrachloride toxicity

BACKGROUND AND OBJECTIVE

Picroliv, isolated from the root and rhizome of Picrorhiza kurroa, is known to have significant hepatoprotective activity. Its effects against Entamoeba histolytica induced liver damage are not studied. This study aims to evaluate the hepatoprotective action of picroliv against the hepatotoxic changes induced by carbon tetrachloride (CCl(4)) and E. histolytica infection in three animal models.

METHODS

Mastomys, gerbils and albino Druckray rats were used in this study. A total of 30 animals were used for each model and divided into five groups of six animals each. Group I consisted of normal animals. The rest received six doses of CCl(4) intraperitoneally. Group II served as hepatotoxic control. The remaining animals were infected intraperitoneally with E. histolytica trophozoites, of which group III was the hepatotoxic plus amoeba infected control. The remaining animals were divided into two groups, one received hepatoprotective agent picroliv and the other silymarin. All animals were sacrificed seven days post amoeba infection.

RESULTS

Increase in the enzyme levels induced by CCl(4) was further elevated after E. histolytica infection. Pinpoint abscesses were found to develop only in gerbils after E. histolytica infection. Picroliv was found to possess hepatoprotective activity against amoebic liver abscess.

INTERPRETATION AND CONCLUSION

Significant recovery obtained in serum enzyme levels in all animal models and against amoebic liver abscess in gerbils on treatment with picroliv indicated that picroliv possesses therapeutic activity against E. histolytica induced hepatic damage.

Antiamoebic and toxicity studies of a carbamic acid derivative and its therapeutic effect in a hamster model of hepatic amoebiasis

Amoebiasis is an important public health problem in developing countries. Entamoeba histolytica, the causative agent of amoebiasis, may develop resistance to nitroimidazoles, a group of drugs considered to be the most effective against this parasitic disease. Therefore, research on new drugs for the treatment of this common infection still constitutes an important therapeutic demand. In the present study we determined the effects of a carbamate derivative, ethyl 4-chlorophenylcarbamate (C4), on trophozoites of E. histolytica strain HM-1:IMSS. C4 was subject to various toxicity tests, including the determination of mutagenicity for bacterial DNA and changes in the enzymatic activities of eukaryotic cells. Genotoxicity studies were performed by the mutagenicity Ames test (plate incorporation and preincubation methods) with Salmonella enterica serovar Typhimurium, with or without metabolic activation produced by the S9 fraction of rat liver. C4 toxicity studies were performed by measuring enzymatic activity in eukaryotic cells by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide-formazan test with Fischer 344 rat hepatocytes. C4 did not induce either frame-shift mutations in S. enterica serovar Typhimurium TA97 or TA98 or base pair substitutions in strains TA100 and TA102. The compound was not toxic for cultured rat hepatic cells. Trophozoites treated with 100 microg of C4 per ml were inhibited 97.88% at 48 h of culture; moreover, damage to the amoebae was also confirmed by electron microscopy. The antiamoebic activity of C4 was evaluated by using an in vivo model of amoebic liver abscess in hamsters. Doses of 75 and 100 mg/100 g of body weight reduced the extent of the amoebic liver abscess by 84 and 94%, respectively. These results justify further studies to clearly validate whether C4 is a new suitable antiamoebic drug.

Amebic liver abscess with bacterial superinfection in a patient with no epidemiologic risk factors

The amebic liver abscess is uncommon in developed countries like Spain, but the incidence is increasing probably due to the migratory movements of the population. We report a case of an amebic abscess, initially unsuspected due to the absence of epidemiologic risk factors and the negative serology for amebiasis, in the early stages of the disease.

Cysteine proteinase activity is required for survival of the parasite in experimental acute amoebic liver abscesses in hamsters

Axenic trophozoites of Entamoeba histolytica strain HM1-IMSS grown in vitro in the presence of E-64, a potent irreversible inhibitor of cysteine proteinases, preserved their viability, their rate of replication, their resistance to complement, their haemolytic capacity and their ability to destroy target cells, despite complete inhibition of total cysteine proteinase activity. On the other hand, their erythrophagocytic capacity and their ability to decrease TER of MDCK cells was partially decreased. The same trophozoites injected into the portal vein of hamsters receiving a maintaining dose of E-64 failed to cause tissue damage and were rapidly eliminated. Our results suggest that amoebic cysteine proteinase activity is not required for amoebic functions in in vitro conditions, but that it becomes necessary for survival of trophozoites in in vivo conditions, whatever other role (if any) it may play in the parasite's virulence.

Features distinguishing amoebic from pyogenic liver abscess: a review of 577 adult cases

Distinguishing amoebic from pyogenic liver abscesses is crucial because their treatments and prognoses differ. We retrospectively reviewed the medical records of 577 adults with liver abscess in order to identify clinical, laboratory, and radiographic factors useful in differentiating these microbial aetiologies. Presumptive diagnoses of amoebic (n = 471; 82%) vs. pyogenic (n = 106; 18%) abscess were based upon amoebic serology, microbiological culture results, and response to therapy. Patients with amoebic abscess were more likely to be young males with a tender, solitary, right lobe abscess (P = 0.012). Univariate analysis found patients with pyogenic abscess more likely to be over 50 years old, with a history of diabetes and jaundice, with pulmonary findings, multiple abscesses, amoebic serology titres <1:256 IU, and lower levels of serum albumin (P < 0.04). Multivariate logistic regression analysis confirmed that age >50 years, pulmonary findings on examination, multiple abscesses, and amebic serology titres <1:256 IU were predictive of pyogenic infection. Several clinical and laboratory parameters can aid in the differentiation of amebic and pyogenic liver abscess. In our setting, amebic abscess is more prevalent and, in most circumstances, can be identified and managed without percutaneous aspiration.

Amebic liver abscess

Amebic liver abscess (ALA) highly endemic in most developing tropical countries is being encountered more frequently in other geographical areas maybe secondary to increased travel to areas where the disease is endemic as well as in the homosexual population. We report a classical clinical case of ALA in a 44 years old man diagnosed by ultrasound and positive seroameba titers who responded to oral imidazoles.

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.

[Liver abscess: a practical approach]

The management of a liver abscess suspected on the basis of clinical and radiological findings is radically different depending on its amoebic or pyogenic etiology. Medical management is usually enough to treat amoebic abscess, the prognosis of which is excellent while percutaneous aspiration puncture, drainage and antibiotics is the rule in pyogenic abscess, the prognosis of which depends on the quickness of diagnosis and risk factors associated. This article first relates a case of liver abscess we had in our service and then propose, on the basis of a literature review, a synthesis of the different characteristics, diagnostic and therapeutic approaches and follow-up of amoebic and pyogenic liver abscesses.