LEFT-SIDED AMOEBIC LIVER ABSCESS WITH PULMONARY INVOLVEMENT, PERICARDITIS, AND PSEUDOCHOLINESTERASE DEFICIENCY

Use of PCR in the diagnosis of pericardial amebiasis: a case report and systematic review of the literature

Background

Entamoeba histolytica (E. histolytica) is rarely identified as a cause of amebic pericarditis. We report a case of amebic pericarditis complicated by cardiac tamponade, in which the diagnosis was missed initially and was made retrospectively by polymerase chain reaction (PCR) testing of a stored sample of pericardial fluid. Furthermore, we performed a systematic review of the literature on amebic pericarditis.

Case presentation

A 71-year-old Japanese man who had a history of sexual intercourse with several commercial sex workers 4 months previously, presented to our hospital with left chest pain and cough. He was admitted on suspicion of pericarditis. On hospital day 7, he developed cardiac tamponade requiring urgent pericardiocentesis. The patient’s symptoms temporarily improved, but 1 month later, he returned with fever and abdominal pain, and multiple liver lesions were found in the right lobe. Polymerase chain reaction of the aspiration fluid of the liver lesion and pericardial and pleural fluid stored from the previous hospitalization were all positive for E. histolytica. Together with the positive serum antibody for E. histolytica, a diagnosis of amebic pericarditis was made. Notably, the diagnosis was missed initially and was made retrospectively by performing PCR testing. The patient improved with metronidazole 750 mg thrice daily for 14 days, followed by paromomycin 500 mg thrice daily for 10 days.

Conclusions

This case suggests that, although only 122 cases of amebic pericarditis have been reported, clinicians should be aware of E. histolytica as a potential causative pathogen. The polymerase chain reaction method was used to detect E. histolytica in the pericardial effusion and was found to be useful for the diagnosis of amebic pericarditis in addition to the positive results for the serum antibody testing for E. histolytica. Because of the high mortality associated with delayed treatment, prompt diagnosis should be made.

Morphological changes during the formation of amoebic liver abscess in vagotomized hamsters

Amoebic liver abscess (ALA) is the main extra-intestinal complication caused by Entamoeba histolytica. Given the histological features of ALA in hamsters and the importance of the vagus nerve in the immune response, the aim of this study was to identify and analyze the major changes in ALA that are caused by a vagotomy. The changes found are related to inflammatory foci and abscess size, the type of collagen formed, and the number of trophozoites in lesions. Male hamsters were divided into three groups: Intact animals (IA) and those undergoing a false operation (SHAM) or a subdiaphragmatic vagotomy (VAG). In each group, E. histolytica trophozoites or culture medium (CM) were inoculated in hamsters by the intrahepatic route, and then euthanized at 6h, 12h, 24h, 48h, 4d or 7d post-infection. Initially the growth of the abscess was more rapid in the VAG group, but at day 7 it was faster in the IA and SHAM groups. VAG animals showed a higher quantity of type III collagen than the IA and SHAM groups. A larger number of amoebic trophozoites/mm² was observed up to day 4 in VAG hamsters (23.3±2.19) compared to IA (14.6±0.23) and SHAM (6.13±0.87) animals. This parameter decreased by day 7 in VAG (13.4±0.87) with respect to IA (24.7±1.47) and SHAM (21.7±1.48). The results show that a subdiaphragmatic vagotomy influenced the development of ALA in hamsters, suggesting a modification of the morphological structure of damaged hepatic tissue.

Diagnostic value of liver function tests and Entamoeba histolytica antibody studies in East Africans

Liver function tests and Entamoeba histolytica (E.H.) antibody titres have been studied in a variety of tropical and liver diseases. Patients with hepatic amoebiasis had a raised E.H. antibody titre and tended to have a low pseudocholinesterase activity. In two cases of amoebic liver abscess, which were treated by aspiration and emetine, there was a remarkable drop in the E.H. antibody titre. In a number of other hepatic and tropical conditions the E.H. antibody titre was not significantly raised and the liver function tests were typical of the various conditions studied.