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Skeletal hydatid disease is a rare parasitic infection caused by the tapeworm Echinococcus granulosus. We present the case of a 30-y-old patient with an echinococcosis of the right leg, who was treated with a preoperative albendazole chemotherapy (4 weeks), followed by radical surgical resection and postoperative albendazole treatment (1 y).
BACKGROUND: Surgery has long been considered the first-choice treatment in patients with echinococcosis of the liver. The poorly predictable outcome of older studies using mebendazole or albendazole confirmed this belief. Since the introduction of a percutaneous technique (PAIR; puncture, aspiration, injection, reaspiration) treatment policy is changing. The actual question is which treatment is preferred in which patients. METHODS: Review of recent literature. RESULTS: Laparoscopic treatment of anteriorly located hepatic cysts is a new surgical technique with high success rates (77%-100%) and low complication (0%-17%) and recurrence rates (0%-9%). Albendazole is superior to mebendazole treatment. Degenerative changes were found in 82% of patients treated with albendazole and in 56% of those treated with mebendazole. The main problem is the high relapse rate: 25% mostly within 2 years. PAIR proved to be superior to albendazole treatment (88% versus 18%) and equally effective as surgery (86% versus 76%). A combined injection of alcohol with polidocanol is a simple alternative to PAIR. Percutaneous evacuation of cyst content (PEVAC) made percutaneous treatment accessible to patients with complicated cysts. CONCLUSIONS: Albendazole is the first-choice treatment in patients with univesicular cysts. PAIR or combined injection of alcohol with polidocanol is indicated when pain is intractable or albendazole fails. In patients with multivesicular cysts, PEVAC is a better choice. Surgery is the first-choice treatment only when the expertise of percutaneous treatment is not available or when percutaneous treatment fails.
Human cystic echinococcosis (CE) caused by infection with a larval stage of Echinococcus granulosus is a serious public health problem in West China. Because CE is a zoonosis, dogs and livestock are important hosts in transmission. Tibetans, especially teenagers, have a natural relationship with these definitive and intermediate hosts in West China and although some areas of Tibet are therefore CE-endemic, few, if any, detailed community studies have been reported. A total of 451 Tibetan school pupils living in rural Tianzhou County in Gansu Province in West China were investigated by mass ELISA and IHA with ultrasound scanning back-up, and positivity rates were found to be 9.5% and 1.6%, respectively, with 0.98% confirmation of hepatic CE in four asymptomatic cases. Seropositivity rates varied with age between 6.2% and 13.2%. IHA found that females had a significantly greater risk of infection than males, a ratio of about 3:1. Age-specific immunopositive rates increased from 6.2% in the 8-13-years age group to 13.2% in those aged over 18. The study found that keeping dogs and herding animals had no effect on rates of infection but that the number of sheep owned by a family correlated with infection rates. The rate of infection in people who hunted was significantly higher than in those who did not. Level of education was found to have no effect on rates of infection.
Information on parasite viability in alveolar echinococcosis (AE) cannot be obtained by conventional imaging techniques. We evaluated the glucose metabolism of AE lesions by use of [18F]fluorodeoxyglucose positron emission tomography (FDG-PET) in 12 inoperable patients. Eight patients showed either perilesional or focal enhancement ("hot spots"), whereas 4 patients had nonenhancing (metabolically inactive) lesions. With PET, necrotic parasitic lesions and areas of enhanced metabolic activity could be clearly discriminated. Most notably, 3 of 8 patients with metabolically active lesions who were reexamined after chemotherapy treatment clearly showed improvement: the initial surrounding hot spots had disappeared in 2 of them, and had significantly decreased in 1. PET may prove valuable in assessing the efficacy of chemotherapy by showing the disappearance of metabolic activity and may also be useful for timely detection of relapses and metastases. Although costly and not readily available, FDG-PET is a promising tool toward improved management of AE and may thus help lower costs of long-term chemotherapy.
Using meta-analysis methodology, we compared the clinical outcomes for 769 patients with hepatic cystic echinococcosis treated with percutaneous aspiration-injection-reaspiration (PAIR) plus albendazole or mebendazole (group 1) with 952 era-matched historical control subjects undergoing surgical intervention (group 2). The rate of clinical and parasitologic cure (P<.0001) was greater in patients receiving PAIR plus chemotherapy. Disease recurrence (P<.0001), major complications (anaphylaxis, biliary fistula, cyst infection, liver/intra-abdominal abscess, and sepsis; P<.0001), minor complications (P<.0001), and death (P<.0824) occurred more frequently among surgical control subjects. Fever (P<.002) and minor allergic reactions subjects (P<.0001) were more common among PAIR-treated subjects. The mean durations of hospital stay were 2.4 days for group 1 and 15.0 days for group 2 (P<.001). Compared with surgery, PAIR plus chemotherapy is associated with greater clinical and parasitologic efficacy; lower rates of morbidity, mortality, and disease recurrence; and shorter hospital stays.
Alveolar echinococcosis (AE) is a rare and often fatal disease characterized by a tumorlike expansion of the metacestode Echinococcus multilocularis in the liver. Because of the severe side effects of therapy with benzimidazoles, we treated a patient with recombinant interferon gamma at a dose of 250 microg over a 3-day period once a month. Disease progression was not detected during the observed period of 18 months. Following stimulation with crude Echinococcus antigen, mRNA from interleukin 5 was still detected in peripheral blood mononuclear cells by means of reverse transcriptase polymerase chain reaction analysis, and expression of interleukin 10 in T lymphocytes (as measured by fluorescence-associated cell sorting of intracellular cytokines) was elevated. These results indicate that bolus therapy with interferon gamma has some clinical effect but does not result in a change in the T helper 2 lymphocyte-dominated immune response to this parasite.
Echinococcosis is the most widespread, serious human cestode infection in the world. Isolated retrovesical cyst hydatid is extremely rare in children and mostly causes symptoms because of its pressure on adjacent organs. We report on the case of an 8-year-old girl with an isolated retrovesical cyst hydatid. Final diagnosis was established after histological examination, whereas imaging techniques failed to establish the diagnosis.
Primary multiple intracerebral echinococcosis is a very rare disorder particularly in children. In this case report we discuss the details of clinical presentation and management in a young child. We also highlight for the first time non-iatrogenic 'water lily' appearance of the lesion on computed tomography of the head.
During the years 1936 through 1978, 60 cases received surgical intervention for alveolar echinococcosis of the liver. The resectability and operative mortality rate were 64.0% (16/25) and 43.8% (7/16) before 1968, but 54.3% (19/35) and zero (0/19) thereafter. Establishment of clinical staging and criteria for justifying radical resection of a given lesion, combined with systematic evaluation of all hepatic vasculatures, contributed to improvement of the result. The long-term prognosis of the disease, unless resected, has been exclusively poor. A mass screening program, which became possible by the development of serologic tests, has covered a population of over 140,000 in the endemic area and been of value in detecting the disease in its early developmental stage. The disease should be recognized even in currently unaffected areas since the cestode has a fairly wide geographic distribution including the United States.
Nineteen cases of proven hepatic alveolar echinococcosis were examined by magnetic resonance (MR) and the results were compared with CT. Fibrous and parasitic tissue showed low signal both on T1- and, generally, on T2-weighted images. In a few cases a high signal on T2-weighted images may be observed, due either to central necrotic zones or to small peripheral cysts. Central necrosis was more easily identified by MR than by CT. However, MR seemed to be less effective than CT in allowing us to reach a positive diagnosis, due to its inability to show microcalcifications. In addition, MR may not reveal small lesions. In most cases T1-weighted images revealed more clearly than CT did the margins of the lesions and the hepatic extension, especially to hepatic veins, vena cava, and perihepatic spaces.
We have presented a case of osseous echinococcosis and have reviewed the pathogenesis, pathology, diagnosis, and current treatment methods.
A sensitive method is described for the simultaneous determination of mebendazole and hydroxymebendazole using flubendazole as an internal standard. The analytes were isolated with a single chloroform extraction from 1.0 ml of alkalinized plasma or cyst liquid samples. Separation and quantitation were performed with high-performance liquid chromatography with electrochemical detection. The limit of detection for mebendazole and hydroxymebendazole was approximately 5 and 2.5 ng/ml, respectively. The accuracy of the method was confirmed for mebendazole by a good correlation with an existing radioimmunoassay method. The method was applied for monitoring mebendazole therapy in echinococcosis patients. The results presented support the necessity of such monitoring, as most of the observed peak plasma concentrations did not reach the level regarded as minimal for therapeutic effect.
BACKGROUND: Alveolar echinococcosis (AE) of the liver is a rare and severe parasitic disease. It behaves like a slow-growing liver cancer, and liver transplantation (LT) has been proposed in advanced cases since 1985. The aim of this retrospective study was to collect all AE transplant cases in Europe, analyze the results, and specify the usefulness of LT for this unusual indication. METHODS: A questionnaire was sent to 83 LT centers from July 1996 to December 1999. RESULTS: Sixty-five centers responded: 45 AE patients (mean age, 45.8 years) underwent an LT procedure at 16 LT centers. The mean interval between diagnosis and LT was 5 years. One patient died during the hepatectomy phase. Five-year survival was 71%. Five-year survival without recurrence was 58%. The nine early deaths were mostly related to bacterial or fungal infections, or both, in patients in bad condition when LT was performed. Six patients had a graft AE reinfection. Five late deaths were related directly to ongoing AE. In the other cases, benzimidazole (BZM) therapy seemed to stabilize AE residues. CONCLUSIONS: This unique experience indicates that LT is feasible for life-threatening AE. Specific management is needed to optimize the results: earlier decision for LT in incurable symptomatic biliary AE, pre- and post-LT BZM therapy, meticulous pre-LT evaluation to identify extrahepatic extension, and an immunosuppressive regimen kept to a minimum.
We have evaluated the use of sheep red-blood cells stabilised in various ways in indirect haemagglutination tests on the sera of 21 surgically confirmed cases of echinococcosis, and on control sera. Tests with Double-Aldehyde-Stabilised cells-treated sequentially with pyruvic aldehyde, tannic acid and glutaraldehyde-were more sensitive than tests with the cells treated only with formaldehyde, glutaraldehyde or pyruvic aldehyde, and subsequently tanned.
To investigate the role of T lymphocytes in the immune response to Echinococcus granulosus, using sheep hydatid fluid (SHF) and antigen B (AgB), we generated T-cell lines from patients with active, transitional and inactive hydatid cysts. We established 16 T-cell lines, eight specific to SHF and eight specific to AgB. At surface phenotyping 88-98% of cells displayed the helper/inducer CD4 antigen. In all patients, at all clinical stages of hydatid cyst disease, T-cell stimulation with SHF and AgB invariably amplified a large number of almost identical Vbeta subfamily fragments. Irrespective of antigen-specificity, the two cell lines from the patient with an inactive cyst had a Th1 profile, because they exclusively expressed and produced IFN-gamma. Conversely, the T-cell lines derived from the seven patients with active and transitional hydatid cysts had mixed Th1/Th2 and Th0 clones. The functional characteristics of the 16 T-cell lines differed markedly in the various clinical stages of cystic echinococcosis, thus providing new in vitro evidence that Th1 lymphocytes contribute decisively to the inactive stage of hydatid disease, Th2 lymphocytes in the active and transitional stages. The parasite-specific T-cell lines, especially the two Th1 lines from the patient with an inactive cyst, may help identify Th1 protective epitopes on SHF and AgB.
The aim of this work was to identify the immunodominant regions of the Em18 antigen to improve the specificity in diagnosis of alveolar echinococcosis (AE). Two recombinant antigens ReEm18-1 and ReEm18-2, which have the same sequence except that nine amino acid residues are absent in ReEm18-2, were tested by ELISA and Western Blot (WB) for their diagnostic efficiency. Serological evaluation of the two antigens demonstrated that the sensitivity of both antigens was 95.5% in ELISA and WB, and the specificity was 93.6% and 95.7% in ELISA, and 81.4% and 82.9% in WB, respectively. Five more expression clones (EmS1-EmS5), which contain different regions of the Em18 sequence, were constructed for defining the immunodominant regions of the antigen. Fourteen monoclonal antibodies (mAbs) against ReEm18-2 antigen and the sera from different groups of patients were used to identify the epitope regions of the five antigen fragments. Results showed that the epitopes recognized by the mAbs are located in the N-terminal third of the sequence, but the immunodominant area recognized by native serum antibodies may be located further downstream (C-terminal) in the sequence. The nonspecific cross-reactivity is due to epitopes present in the C-terminal third of the sequence. The antigen fragments that contain the first two-thirds of the sequence have the same sensitivity to AE sera as those of the ReEm18-1 and ReEm18-2 antigens, but removal of the C-terminal third of the sequence improved the specificity of the assay from 93.6% to 99.3% (ELISA) and 81.4% to 90.7% (WB). We conclude that the necessary part of the ReEm18 antigen sequence for AE diagnosis is the N-terminal half to two-thirds of the entire sequence.
Infection with the cestode Echinococcus multilocularis causes human alveolar echinococcosis (AE), a life-threatening disease affecting primarily the liver. Despite the severity of AE, clinical symptoms often develop only many years after infection, which suggests that E. multilocularis has developed mechanisms which depress anti-parasite immune response, thus favouring immune evasion. In this study we examined the production of cytokines, chemokines and the expression of CD molecules on peripheral blood mononuclear cells (PBMC) from AE patients and healthy controls in response to E. multilocularis metacestode culture supernatant, viable E. multilocularis vesicles and E. multilocularis vesicle fluid antigen in vitro. After 48 h of co-culture, E. multilocularis metacestode culture supernatant and E. multilocularis vesicles depressed the release of the proinflammatory cytokine interleukin (IL)-12 by PBMC. This effect was dose-dependent and a suppression of tumour necrosis factor (TNF)-alpha and IL-12 was observed even when PBMC were activated with lipopolysaccharide (LPS). Comparing proinflammatory cytokine release by AE patients and controls showed that the release of IL-12 and TNF-alpha was reduced in AE patients, which was accompanied by an increased number of CD4+ CD25+ cells and a reduced release of the Th2 type chemokine CCL17 (thymus and activation regulated chemokine, TARC), suggesting an anti-inflammatory response to E. multilocularis metacestode in AE patients. Instead the production of interferon (IFN)-gamma and the expression of CD28 on CD4+ T cells were increased in PBMC from AE patients when compared to controls. This was accompanied by a higher release of the Th2-type chemokine CCL22 (macrophage derived chemokine, MDC) supporting that E. multilocularis also generates proinflammatory immune responses. These results indicate that E. multilocularis antigens modulated both regulatory and inflammatory Th1 and Th2 cytokines and chemokines. Such a mixed profile might be required for limiting parasite growth but also for reducing periparasitic tissue and organ damage in the host.
Infection of cotton rats with Echinococcus multilocularis or vaccination with BCG, or its cell walls, activates peritoneal cells to kill the protoscolices of the parasite in vitro and protects laboratory animals against the cestode. To determine whether other 'non-specific' stimuli would also protect against the parasite, cotton rat peritoneal cells were activated in vivo with PHA and transferred to recipients 3 days later. The recipients, controls and PHA-treated animals were then inoculated with the parasite; 3 days after inoculation other untreated infected animals received cells activated in vivo with PHA. PHA-activated cells, the PHA treatment itself and immunization with a homogenate of the parasite stimulated a leucocytosis and protected against infection by E. multilocularis; carrageenan abrogated protection in PHA-treated animals. The results of this study confirm that protection against echinococcosis can be induced non-specifically; these results suggest that immunity in hydatid disease may have an important component in the inflammatory reaction.