Outcome of hepatic amebic abscesses managed with three different therapeutic strategies

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.

[Amebic liver abscess: medical treatment or percutaneous aspiration?]

Amebic liver abscess is an emergent disease in Spain due to immigration and travel to endemic countries. Although mainly pharmacological, treatment can sometimes require drainage, especially when there is a high risk of rupture due to location or size. We report a case of amebic liver abscess that, due to its large size and lack of response to metronidazole therapy, required percutaneous drainage. This technique, with ultrasound-guided percutaneous aspiration, would be indicated in lesions with a diameter of > 5 cm, abscesses of the left lobe, and those unresponsive to medical treatment.

Pyogenic and amebic liver abscesses

Pyogenic and amebic liver abscesses are the two most common hepatic abscesses. Amebic abscesses are more common in areas where Entamoeba histolytica is endemic, whereas pyogenic abscesses are more common in developed countries. Pyogenic abscess severity is dependent on the bacterial source and the underlying condition of the patient. Amebic liver abscess is more prevalent in individuals with suppressed cell-mediated immunity, men, and younger people. The right lobe of the liver is the most likely site of infection in both types of hepatic abscess. Patients usually present with a combination of fever, right-upper-quadrant abdominal pain, and hepatomegaly. Jaundice is more common in the pyogenic abscess. The diagnosis is often delayed and is usually made through a combination of radiologic imaging and microbiologic, serologic, and percutaneous techniques. Treatment involves antibiotics along with percutaneous drainage or surgery.

[Therapy of tropical diseases after returning from travel]

Most tropical diseases imported by travelers can be treated quite effectively. Human endoparasites belong to the protozoa and worms. Protozoa can be seen as microparasites, characterized by short generation periods and high rates of reproduction within a host--consequently the diseases mainly are of short duration. Effective drugs are available for malaria, amebiasis and other intestinal protozoa as well as for leishmaniasis. Resistance, however, sometimes is a problem. Worms are macroparasites that generally do not reproduce within a host--teleologically speaking because otherwise they would rapidly damage their own basis of living. Accordingly, severe worm disease is rarely found in travelers. Levels of anthelminthic resistances so far are low. The most important worm disease in travelers is schistosomiasis, a disease that also can be treated effectively if diagnosed early.

[Amoebic liver abscess. Study of 20 cases with literature review]

PURPOSE

The management of amoebic liver abscess includes antiamoebic drugs combined or not with percutaneous puncture or surgical drainage. This study was to suggest a decision tree for the therapeutic approach of such feature.

METHODS

We report a retrospective analysis of 20 imported cases with amoebic liver abscesses admitted at the Department of Tropical Diseases during 1995-1999 at the Bordeaux University Hospital Centre, France, and a review of the literature.

RESULTS

The twenty patients were 14 males and 6 females, mainly 20 to 40 years old. The clinical presentation was mainly accounting a painful liver enlargement with hyperthermia. The echographic picture was mostly represented by a unique liver element located at the liver right lobe. They were numerous in an HIV infected patient. Thirteen patients have been treated using a medical therapeutic approach. A percutaneous puncture has been necessary for 4 cases. A percutaneous drainage has been realised for two patients as regard to the persistence of the hepatalgia occurrence. A surgical drainage has been experienced by two patients after a lack of efficacy of a percutaneous drainage, after rupture of an abscess treated medically, respectively. A review of the literature and the analysis of the 20 cases history have been used to determine a therapeutic algorithm.

CONCLUSION

The occurrence of immediate complications at onset must indicate a first line surgical drainage procedure. Beside this situation, risk factors for rupture must be assessed (high size abscess, pejorative localization), as well as poor prognosis feature (liver failure, bacteraemia). If no pejorative condition occurs, a first-line exclusive medical approach can be undertaken with a clinical efficacy evaluation at H72. Otherwise, the indication of the percutaneous drainage must be discussed.

Amebiasis

More than 80% of cases of amebic liver abscess can be managed with a 14-day course of intravenous or oral metronidazole. In cases of suspected amebic liver abscess, treatment should be started before diagnostic confirmation. If no clinical improvement is evident by 72 to 96 hours, treatment should be changed to dehydroemetine and chloroquine. Invasive treatment is necessary only in patients in whom medical treatment fails within 5 days or in whom signs of clinically severe disease are present. A 10-day course with a luminal agent such as paromomycin to eliminate intestinal cysts, which are resistant to imidazoles, should always follow treatment of the liver abscess. Percutaneous catheter drainage is indicated in patients with impending rupture, with a lesion 6 cm or more in diameter, with an abscess located in the left lobe or high in the dome of the right lobe, or in whom medical treatment fails. Although sympathetic pleural effusion is not an indication for drainage, direct pulmonary involvement or spread to pleural or lung tissues requires drainage. Intraperitoneal rupture and peritonitis necessitate open surgical drainage. Only a small minority of amebic liver abscesses are secondarily infected by other organisms. Because relapses are possible, feces should be checked for cysts monthly for several months after therapy.

Ultrasound guided percutaneous drainage of abdominal abscesses in the hands of the clinician: a multicenter Italian study

OBJECTIVE

Image guided percutaneous drainage is a well established therapeutic technique. The results of these procedures, when performed directly by the clinician and under sonographic guidance,in respect to other imaging techniques are not yet clarified.

METHODS

The 886 cases of ultrasound guided drainage were collected from eight italian clinical institutions and the results were analyzed according to location of the abscess, drainage technique, underlying diseases, microbiological findings, immunological patient status and previous surgical intervention.

RESULTS

We observed an overall cure rate of 90.4%. The best results were obtained in hepatic abscesses, both amoebic and pyogenic (cure rate 98.7 and 94.3%). Slightly lower cure rates were obtained in abdominal and splenic abscesses, postoperative collections and severely immunocompromised patients. The frequency of complications was low (6.6%) and mostly related to catheter drainage. No drainage-related deaths occurred.

CONCLUSIONS

The study confirms the high clinical efficiency and safety of ultrasound guided percutaneous drainage, even when performed directly by the clinician. The sonographic guidance showed similar efficacy, more manageability and lower costs than other imaging techniques and it should be preferred whenever possible. For hepatic abscesses, ultrasound guided needle aspiration showed good results and less complications than catheter drainage.

Percutaneous management of hepatic abscess: a perspective by interventional radiologists

Techniques for treating hepatic abscess have evolved rapidly during the past decade. For many years, the traditional treatment was surgical drainage. The development of modern imaging modalities, such as CT and US, has not only made the diagnosis more certain, but has also introduced a variety of percutaneous treatment options. Pyogenic hepatic abscess is now accepted as a medical/radiologic disease requiring surgical intervention only for correctable offending causes or for failed radiologic evacuation. Drainage via an indwelling catheter has been the traditional method of percutaneous treatment. However, indwelling catheters have disadvantages, including patient discomfort, the nuisance of catheter maintenance, and postprocedural complications. The technique of simple aspiration and intracavitary antibiotics as advocated by McFadzian et al, with excellent results confirmed by Giorgio et al, is a promising alternative to prolonged catheter drainage, and may be the biggest advancement in the management of hepatic abscess in 80 years. Surgeons have recently accepted radiologic drainage; now we need to see if interventional radiologists and surgeons will accept evacuation without indwelling catheter drainage. The role of interventional techniques for nonpyogenic hepatic abscesses will vary considerably. Mortality will still occur in the pyogenic varieties but should be related to underlying disease rather than the abscess itself.

Tropical liver abscess

Forty-one consecutive cases of liver abscesses seen at the National University Hospital, Singapore from 1988 to 1994 were reviewed. Twenty-seven cases (65%) were pyogenic, six (15%) amoebic, two (5%) tuberculous and six (15%) indeterminate. The predominance of pyogenic abscesses is in marked contrast to previous studies from the region a decade ago in which amoebic abscesses were the commonest type. The commonest pathogen causing pyogenic abscess was Klebsiella pneumoniae. Two cases were due to Mycobacterium tuberculosis, and this organism needs to be actively looked for in smears and cultures of aspirated material. As the majority of organisms isolated were resistant to ampicillin, empirical antibiotic treatment for suspected pyogenic abscess should include gentamicin or a cephalosporin. Percutaneous needle aspiration of the abscess was performed for 85% of pyogenic abscesses and surgery was necessary in only two cases because of complications. We found that percutaneous aspiration of liver abscess is helpful to confirm the diagnosis, provides a better bacteriological culture yield, gives a good outcome, and may uncover clinically unsuspected conditions like malignancy and tuberculoma which may mimic the presentation of liver abscesses. We recommend routine cytological examination of aspirated abscess material as well as stains and cultures for acid-fast bacilli.

Detection of pathogenic Entamoeba histolytica DNA in liver abscess fluid by polymerase chain reaction

A sensitive method for detection of pathogenic Entamoeba histolytica DNA in drained fluids from liver abscess patients, using the polymerase chain reaction (PCR), has been developed. The PCR employs oligonucleotide primers specific for the gene encoding the 30 kDa molecule of pathogenic E. histolytica. Liver abscess fluids (19 samples), from 14 patients with a presumptive amebic liver abscess, were examined microscopically and by the PCR method. Only two of the 19 samples were positive microscopically, whereas all 19 samples tested positive by PCR. This technique can be used to confirm the diagnosis of amebic liver abscess.

Hepatic abscesses in immunocompromised patients: ultrasonically guided percutaneous drainage

Ultrasonically guided percutaneous drainage (US-PD) is considered first-line therapy for hepatic abscesses, but no data are available on its efficacy in severely immunocompromised patients. Therefore, we examined 15 such patients in whom one or more hepatic abscesses of different etiology were treated with US-PD. Eleven patients underwent needle aspiration and four had catheter drainage under US guidance. In 12 cases we achieved complete healing of the abscesses. In one case, clinical improvement was obtained but surgery was required for cure. In another case (fungal abscess in AIDS), we had no improvement and the patient died. No procedural complications were observed. Seven patients died during the follow-up periods of up to 49 months from their underlying disease. We conclude that US-PD must be considered the therapy of choice for hepatic abscess (except the fungal lesions) in severely immunocompromised patients.