Therapy of human hydatid disease with mebendazole and albendazole

The types and timing of the degenerative changes seen in the cysts during and after benzimidazole treatment of cystic echinococcosis

In a large-scale Bulgarian study, 122 patients with abdominal and/or lung echinococcosis were randomly selected for treatment with albendazole or mebendazole. The main aims were to evaluate the effect of each drug on the hydatid cysts, to follow the changes in cyst morphology during and after treatment, and to determine how quickly each drug produced the first, detectable, degenerative changes in the cysts. Follow-up was based on periodic ultrasonography, chest radiography and computed tomography. The abdominal cysts were categorised as small (<5 cm in diameter) or large. As albendazole treatment had effects that were almost identical to those of mebendazole treatment, the results for the two drugs were combined. In the lungs and, particularly, in the abdomen, the size of the cysts being treated influenced the character and timing of the degenerative changes seen in them. The initial change seen in each abdominal cyst was detachment of the endocyst, which occurred 1-3 months (small cysts) or 2-5 months (large cysts) after the initiation of treatment (P<0.05). The abdominal cysts then developed a hyper-echoic/hyper-dense appearance, became smaller, and finally disappeared 3.3-9.3 months (small cysts) or 5.6-13.9 months (large cysts) after treatment began (P<0.05). The first degenerative change noted in the lung cysts was cyst rupture, which occurred as early as day 10 of therapy but was generally observed 1 or 2 months after treatment began. After their complete evacuation, the ruptured lung cysts shrank and became deformed, some disappearing within 5-9 months of the initiation of treatment. The degenerative changes recorded, which began significantly earlier in the lung cysts than in abdominal cysts, indicate serious damage to the cysts and the parasiticidal, curative effect of each of the two benzimidazoles employed.

Hydatid cyst of spleen: a diagnostic challenge

Although splenic involvement alone in hydatid disease is very rare, spleen is the third most common organ involved in hydatid disease. The rarity of splenic hydatid disease poses a diagnostic challenge for clinicians, particularly in non-endemic areas. As the hydatid cyst can present as a simple cyst without having the classic serological and imaging features, and later can lead to life-threatening complications like anaphylaxis, hydatid disease of spleen should be considered in differential in every patient in endemic areas with cystic lesion of spleen until proved otherwise. The author used the keyword “splenic hydatid cyst” in PubMed and reviewed the scientific literatures published from January 1965 to June 2012. The present review is to accentuate the incidence, classification, clinical and pathophysiological features, differential diagnosis, diagnostic modalities, and treatment choices of hydatid cyst of spleen along with follow-up strategy and newer treatment approaches.

Management of a ruptured hydatid cyst involving the ribs: Dealing with a challenging case and review of the literature

INTRODUCTION

Hydatid liver cysts can rupture into neighboring structures in 15-60% of patients, and most often involves the bile duct, the bronchi, and the peritoneal/pleural cavities. Rarely, chest or abdominal wall involvement occurs that are challenging to manage. This case report and literature review describes the management of patients with chest wall and rib invasion.

PRESENTATION OF CASE

A 74-year-old woman, of Spanish origin, presented with right upper quadrant abdominal pain and tender localized swelling. On computer tomography (CT) assessment, the rupture of a hydatid cyst into the right anterior chest wall was identified. Partial involvement of the 10th and 11th rib were noted. The diagnosis was confirmed by a serological test. Surgical treatment involved a radical en bloc right hepatic resection together with resection of the involved ribs, diaphragm and subcutaneous tissue. Primary diaphragm and wall closures were performed. The postoperative course was uneventful with three weeks of albendazole treatment. CT follow-up at six months demonstrated the absence of recurrence.

DISCUSSION

Complete resection is the gold standard treatment of patients with hydatid cysts with the aim to remove all parasitic and pericystic tissues.

CONCLUSION

The present report illustrates that an aggressive surgical en bloc resection is feasible and should be preferred for the treatment of hydatid cysts with rupture into the chest wall, even when the ribs are involved.

Role of albendazole in the management of hydatid cyst liver

BACKGROUND/AIM

Hydatidosis has a worldwide distribution and the liver is the most common organ involved. Hydatid cysts of the liver can be managed either by nonoperative or operative methods. Nonoperative methods include chemotherapy and percutaneous treatment. The study aimed at understanding the effect of albendazole therapy on the viability of protoscoleces and recurrence rate of hydatid disease of the liver.

PATIENTS AND METHODS

The study was conducted at Sher-i-Kashmir Institute of Medical Sciences, Soura, Srinagar, Kashmir, India, over a period of 2 years from January 2002 to December 2003, with further follow-up of 5 years. The study included 72 cases in the age group of 17-66 years, comprising 39 males and 33 females. The patients were randomized into two groups of 36 patients each. In group A, patients were directly subjected to surgery, while in group B, patients were administered albendazole for 12 weeks preoperatively, followed by a further postoperative course for 12 weeks.

RESULTS

Of patients who received albendazole therapy, no patient had viable cysts at the time of surgery, as compared to 94.45% of the patients who did not receive any preoperative albendazole (P<0.01). In patients who did not receive any albendazole therapy, recurrence rate was 16.66%, while no recurrence was seen in patients who received albendazole therapy (P≤0.05).

CONCLUSION

We conclude that albendazole is an effective adjuvant therapy in the treatment of hydatid liver disease.

Treatment of liver hydatidosis: How to treat an asymptomatic carrier?

Liver hydatidosis is the most common clinical presentation of cystic echinococcosis (CE). Ultrasonographic mass surveys have demonstrated the true prevalence, including the asymptomatic characteristic of the majority of cases, providing new insight into the natural history of the disease. This raises the question of whether to treat or not to treat these patients, due to the high and unsuspected prevalence of CE. The high rate of liver/lung frequencies of cyst localization, the autopsy findings, and the involution of cysts demonstrated in long time follow-up of asymptomatic carriers contribute to this discussion. The decision to treat an asymptomatic patient by surgery, albendazole, or puncture aspiration injection and reaspiration or to wait and watch, is based on conflicting reports in the literature, the lack of complications in untreated patients over time, and the spontaneous disappearance and involution of cysts. All these points contribute to difficulties of individual clinical decisions. The patients should be informed of the reasons and the risks of watchful/waiting without treatment, the possibility of complications, and the risks of the other options. As more information on the natural history of liver hydatidosis is acquired, selection of the best treatment will be come easier. Without this knowledge it would be very difficult to establish definitive rules of treatment. At present, it is possible to manage these patients over time and to wait for the best moment for treatment. Follow-up studies must be conducted to achieve this objective.

Human echinococcosis: a neglected disease

Echinococcosis is among the most neglected parasitic diseases. Development of new drugs and other treatment modalities receives very little attention, if any. In most developed countries, Cystic Echinococcosis (CE) is an imported disease of very low incidence and prevalence and is found almost exclusively in migrants from endemic regions. In endemic regions, predominantly settings with limited resources, patient numbers are high. Whole communities do not have access to appropriate treatment. The choice of treatment modalities is limited because of poor infrastructure and shortage of equipment and drugs. In this context, CE meets the criteria for a neglected disease. Furthermore, the terminology related to the designations around the parasite, its evolution and some therapeutic procedures is not uniform and sometimes inappropriate terms and wrong designations are used based on incorrect concepts. Although all of us know the different aspects of the disease it is pertinent to remember some important points and, above all, to clarify some aspects concerning the hydatid cyst's nomenclature in order to understand better the therapeutic options in the liver locations, particularly the different surgical approaches.

Cardiac involvement with parasitic infections

Parasitic infections previously seen only in developing tropical settings can be currently diagnosed worldwide due to travel and population migration. Some parasites may directly or indirectly affect various anatomical structures of the heart, with infections manifested as myocarditis, pericarditis, pancarditis, or pulmonary hypertension. Thus, it has become quite relevant for clinicians in developed settings to consider parasitic infections in the differential diagnosis of myocardial and pericardial disease anywhere around the globe. Chagas' disease is by far the most important parasitic infection of the heart and one that it is currently considered a global parasitic infection due to the growing migration of populations from areas where these infections are highly endemic to settings where they are not endemic. Current advances in the treatment of African trypanosomiasis offer hope to prevent not only the neurological complications but also the frequently identified cardiac manifestations of this life-threatening parasitic infection. The lack of effective vaccines, optimal chemoprophylaxis, or evidence-based pharmacological therapies to control many of the parasitic diseases of the heart, in particular Chagas' disease, makes this disease one of the most important public health challenges of our time.

Medical treatment of primary extradural solitary lumbar hydatid disease

Hydatid disease of the spine is rare and has a poor prognosis, presenting both diagnostic and therapeutic challenges. Paraplegia is the most serious complication of the disease and is caused by compression of the spinal cord by the cysts. We report a 30-year-old woman with an isolated primary hydatid cyst that responded to treatment with albendazole. She presented with back and right leg pain. MRI of the lumbar spine showed a solitary cyst measuring 2.2 x 2.7 cm, with an intraspinal extension at L4-L5. Physical examination did not reveal any focal deficit and the patient was treated with albendazole drug therapy (400mg daily). After 7 months' treatment, she had improved both clinically and radiologically. Albendazole drug therapy appears to be effective for conservative treatment of patients with primary solitary hydatid disease in the lumbar spine.

Evaluation of oxfendazole, praziquantel and albendazole against cystic echinococcosis: a randomized clinical trial in naturally infected sheep

Background

Cystic Echinococosis (CE) is a zoonotic disease caused by larval stage Echinococcus granulosus. We determined the effects of high dose of Oxfendazole (OXF), combination Oxfendazole/Praziquantel (PZQ), and combination Albendazole (ABZ)/Praziquantel against CE in sheep.

Methodology/Principal Findings

A randomized placebo-controlled trial was carried out on 118 randomly selected ewes. They were randomly assigned to one of the following groups: 1) placebo; 2) OXF 60 mg/Kg of body weight (BW) weekly for four weeks; 3) ABZ 30 mg/Kg BW + PZQ 40 mg/Kg BW weekly for 6 weeks, and 4) OXF 30 mg/Kg BW+ PZQ 40 mg/Kg BW biweekly for 3 administrations (6 weeks). Percent protoscolex (PSC) viability was evaluated using a 0.1% aqueous eosin vital stain for each cyst. “Noninfective” sheep were those that had no viable PSCs; “low-medium infective” were those that had 1% to 60% PSC viability; and “high infective” were those with more than 60% PSC viability. We evaluated 92 of the 118 sheep. ABZ/PZQ led the lowest PSC viability for lung cysts (12.7%), while OXF/PZQ did so for liver cysts (13.5%). The percentage of either “noninfective” or “low-medium infective” sheep was 90%, 93.8% and 88.9% for OXF, ABZ/PZQ and OXF/PZQ group as compared to 50% “noninfective” or “low-medium infective” for placebo. After performing all necropsies, CE prevalence in the flock of sheep was 95.7% (88/92) with a total number of 1094 cysts (12.4 cysts/animal). On average, the two-drug-combination groups resulted pulmonary cysts that were 6 mm smaller and hepatic cysts that were 4.2 mm smaller than placebo (p<0.05).

Conclusions/Significance

We demonstrate that Oxfendazole at 60 mg, combination Oxfendazole/Praziquantel and combination Albendazole/Praziquantel are successful schemas that can be added to control measures in animals and merits further study for the treatment of animal CE. Further investigations on different schedules of monotherapy or combined chemotherapy are needed, as well as studies to evaluate the safety and efficacy of Oxfendazole in humans.

Cystic Echinococcosis (CE) is a near-cosmopolitan parasitic zoonosis that causes economic losses in many regions of the world. This parasitic infection can be regarded as an emerging or re-emerging disease causing considerable losses in livestock production. CE is produced by the larval cystic stage (hydatid) of the dog parasite Echinococcus granulosus. After infective eggs are ingested, cysts develop mainly in lungs and liver of humans and animals (sheep, cattle, pigs, horses, etc). Infected people may require surgery and/or Albendazole-based chemotherapy. In this study, we evaluated the effects of Oxfendazole alone (an antiparasitic drug used in animals), Oxfendazole plus Praziquantel, and Albendazole plus Praziquantel against hydatid cysts in sheep over 4 to 6 weeks of treatment. All of the treatments in this study were efficacious in killing the larval stages and, therefore, in minimizing the risk of a dog acquiring new infections (taenias). These treatment schemes can be added to control measures in animals and eventually could be used for the treatment of human infection. Further investigations on different schedules of monotherapy or combined chemotherapy are needed, as well as studies to evaluate the safety and efficacy of Oxfendazole in humans.

Human cystic echinococcosis: old problems and new perspectives

Cystic echinococcosis (CE) is a widespread chronic endemic helminthic disease caused by infection with metacestodes of the tapeworm Echinococcus granulosus. CE affects humans and has a worldwide prevalence of approximately six million. In this review, we discuss current findings in diagnosis and clinical management of CE and new concepts relating to E. granulosus molecules that directly modulate the host immune responses favouring a strong anti-inflammatory response and perpetuating parasite survival in the host. New insights into the molecular biology of E. granulosus will improve considerably our knowledge of the disease and will provide new potential therapeutic applications to treat or prevent inflammatory immune-mediated disease.

Treatment response of cystic echinococcosis to benzimidazoles: a systematic review

Over the past 30 years, benzimidazoles have increasingly been used to treat cystic echinococcosis (CE). The efficacy of benzimidazoles, however, remains unclear. We systematically searched MEDLINE, EMBASE, SIGLE, and CCTR to identify studies on benzimidazole treatment outcome. A large heterogeneity of methods in 23 reports precluded a meta-analysis of published results. Specialist centres were contacted to provide individual patient data. We conducted survival analyses for cyst response defined as inactive (CE4 or CE5 by the ultrasound-based World Health Organisation [WHO] classification scheme) or as disappeared. We collected data from 711 treated patients with 1,308 cysts from six centres (five countries). Analysis was restricted to 1,159 liver and peritoneal cysts. Overall, 1–2 y after initiation of benzimidazole treatment 50%–75% of active C1 cysts were classified as inactive/disappeared compared to 30%–55% of CE2 and CE3 cysts. Further in analyzing the rate of inactivation/disappearance with regard to cyst size, 50%–60% of cysts <6 cm responded to treatment after 1–2 y compared to 25%–50% of cysts >6 cm. However, 25% of cysts reverted to active status within 1.5 to 2 y after having initially responded and multiple relapses were observed; after the second and third treatment 60% of cysts relapsed within 2 y. We estimated that 2 y after treatment initiation 40% of cysts are still active or become active again. The overall efficacy of benzimidazoles has been overstated in the past. There is an urgent need for a pragmatic randomised controlled trial that compares standardized benzimidazole therapy on responsive cyst stages with the other treatment modalities.

Cystic echinococcosis (CE) is a parasitic infection of worldwide occurrence transmitted to humans by dogs. After infection cysts develop, mainly in the liver and lung. Ultrasound-based staging of cysts into active, transitional, and inactive has opened new venues for treatment and follow-up. Currently four treatment modalities are in use: (1) surgery, (2) percutaneous sterilization techniques, (3) chemotherapy with benzimidazoles, and (4) watch and wait for inactive cysts. However, evidence is insufficient for these four modalities, and determining individual treatment options for patients remains controversial. Medical treatment with benzimidazoles started in the 1970s. Important questions remain unanswered, however, such as efficacy stratified by cyst type and the duration of treatment. We therefore initiated EchinoMEDREV, a collaborative effort to collect individual patient data from patients treated with benzimidazoles and to analyze cyst outcome after initiation of benzimidazole therapy using a common analytical strategy across treatment centres. We found that the efficacy of benzimidazoles has been overstated in the past. Additionally, natural cyst decay has not been taken into account. Evidence from randomized controlled trials is urgently needed to determine the true efficacy of benzimidazoles. Our analysis will help to design benzimidazole trial arms on the basis of the currently available best evidence.

Evaluation of nitazoxanide and oxfendazole efficacy against cystic echinococcosis in naturally infected sheep

Cystic echinococosis (CE) is a public health problem caused by Echinococcus granulosus. We aimed to determine the efficacy of nitazoxanide (NTZ) and oxfendazole (OXF) against CE in naturally infected sheep. A total of 151 ewes were assigned to the following groups: 15 mg/kg of NTZ weekly for five weeks (NTZ5); two rounds of 15 mg/ kg of NTZ a day for five days (NTZ5x2) two weeks apart; 30 mg/kg of OXF a week for 11 weeks (OXF11); 30 mg/kg of OXF plus 15 mg/kg of NTZ a week for 11 weeks (OXF/NTZ); and the control group. OXF11 and OXF/NTZ decreased the number of fertile cysts, increased the number of degenerated cysts, and were more efficacious (49.6-61.2%) against lung cysts and liver cysts (91.8-100%) than any other treatment group. OXF might be an additional strategy for control programs and an optional treatment of human CE after it is licensed.

Mebendazole in parasitic infections other than those caused by soil-transmitted helminths

Mebendazole, a benzimidazole carbamate compound, is currently in use for human medical practice against soil-transmitted helminthiasis (STH) and enterobiasis. However, it has been demonstrated that its spectrum of activity is broad and goes beyond those infections. Several studies provide evidence that this drug, taken at higher doses than used for STH and enterobiasis, could be sufficiently effective on some protozoa, nematodes and cestodes.

Anthelminthic treatment: an adjuvant therapeutic strategy against Echinococcus granulosus

The main goal of the paper is to clarify anthelminthic treatment as an alternative hydatic cyst therapy, its indications and contraindications. Chemotherapy constitutes a non-invasive treatment and is less limited by the patient's status than surgery or PAIR. Many investigators have employed benzoimidazole carbonates for the management of human hydatid disease. Both, albendazole and mebendazole have, a favourable effect in patients suffering from multiorgan and multicystic disease, in inoperable primary liver or lung echinococcosis, and they can also prevent secondary echinococcosis. Chemotherapy is contraindicated for large cysts that are at risk to rupture and for inactive or calcified cysts. The main adverse events are related to changes in liver enzyme levels. The best efficacy is observed with liver, lung, and peritoneal cysts. Certain various factors influence the therapeutic results of medical treatment. The vast majority of the recurring cysts show good susceptibility to re-treatment.

Albendazole as an adjuvant to the standard surgical management of hydatid cyst liver

BACKGROUND

The treatment options for hydatid cyst liver include non-operative and operative methods. Operative methods include conservative and radical procedures. Non-operative methods include chemotherapy and percutaneous treatment of liver hydatidosis.

MATERIAL AND METHODS

The study was conducted at Sher-i-Kashmir Institute of Medical Sciences, Soura, Srinagar, Kashmir, India, over a period of two years from March 2001 to February 2003 with further follow-up of 5-6 years. The study included 64 cases in the age group of 15 years to 64 years, comprising 36 males and 28 females. The aim of the study was to know the effect of preoperative and postoperative albendazole therapy on the viability of protoscolices and recurrence rate of hydatid disease of liver. Patients were divided into four group of 16 each. In group A, patients were directly subjected to surgery. In group B, patients were given albendazole for 8 weeks followed by surgery. In group C, patients were given albendazole for 8 weeks preoperatively followed by further postoperative course for 8 weeks. In group D, patients were first taken for surgery followed by postoperative course of albendazole for 8 weeks.

RESULTS

Out of those patients who received preoperative albendazole only 9.37% had viable cysts at the time of surgery as compared to 96.87% of patients who did not receive any preoperative albendazole. In those patients who did not receive any albendazole therapy, recurrence rate was 18.75% whereas recurrence was 4.16% in patients who received albendazole therapy.

CONCLUSION

We conclude that albendazole is safe and effective adjuvant therapy in the treatment of hydatid liver disease.

The effect of combination therapy with albendazole and praziquantel on hydatid cyst treatment

The standard therapy of hydatid cyst is surgery but, in nonoperable patients and multiple organ involvement, medical therapy may be more useful. The efficacy of drugs especially in short-term treatment of hydatid cyst is unknown. This study was carried out to evaluate the effect of combination therapy with albendazole and praziquantel in the treatment of hydatid diseases. In a nonrandomized quasi-experimental study, nine patients with multiple hydatid cysts were treated with albendazole (400 mg/twice a day) and praziquantel (40 mg/kg per day) twice a week for 4 weeks. This regimen was repeated for three courses with a 2-week interval between each one. The average follow-up period after treatment was 18 months. Response to treatment was assessed through the observation of the symptoms and radiologic findings (computed axial tomography scan, sonography, X-ray). Symptoms disappeared in seven (77.8%) patients and improved partially in two (22.2%) patients. Radiological assessment showed significant improvement in five (55.6%) and partial improvement in four (44.4%) patients. Combination therapy with albendazole and praziquantel is effective in the treatment of hydatid cyst and can be used as an alternative to surgery in disseminated and nonoperable cases.

Albendazole treatment in cystic echinococcosis: pharmacokinetics and clinical efficacy of two different aqueous formulations

The pharmacokinetic (PK) behaviour and clinical efficacy of albendazole (ABZ) against hydatid cysts in mice were assessed after treatment with two different ABZ pharmaceutical formulations. BalbC mice received ABZ (0.5 mg/kg) prepared either as solution or suspension (50 microg/ml) for oral administration (PK study). Blood samples were collected up to 16 h post-treatment and processed to measure ABZ/metabolites concentrations in plasma. The clinical efficacy assessment was performed in BalbC mice infected 8 months earlier with Echinococcus granulosus protoscoleces. Infected animals were allocated into three experimental treatment groups: (a) untreated control, (b) ABZ-solution treated, (c) ABZ-suspension treated. Both treated groups received ABZ (0.5 mg/kg) administered under two different therapeutic schemes: dosing every 48 h over 30 days (regimen I) or treated every 12 h during 15 days (regimen II). Experimental mice were sacrificed 12 h after treatment, and cysts were recovered, weighed and processed for transmission electron microscopy. Enhanced ABZ sulphoxide (the main ABZ metabolite) concentration profiles were measured in animals treated with the ABZ solution. Any positive clinical response was obtained after treatment every 48 h (30 days therapy). However, consistent with the observed PK results, both ABZ formulations were clinically effective in infected mice treated with a 12-h dosing interval (15 days therapy).

Sciatica of nondisc origin: hydatid cyst of the sciatic nerve

✓The authors report on an 81-year-old woman with a primary hydatid cyst located in the posteromedial aspect of the thigh. She presented with sciatica, and the cyst was also associated with neurological dysfunction because of its intra-neural location. Diagnosis of a cyst in a nerve body is very rare, and the one reported here might be the first such case. So far, in all the previously reported cases in which there were also neurological findings, the cysts in the vertebral column were compressing the spinal cord or there was an intrapelvic mass compressing the sciatic nerve. Hydatid cyst should be considered in the differential diagnosis of sciatica, especially when treating patients who live in or have emigrated from areas of the world whereEchinococcus granulosusis prevalent.

Giant hepatic hydatid cyst with sub-fascial extension treated by open minimally invasive surgery: a case report

INTRODUCTION

Hepatic hydatid disease can be successfully treated by a variety of modalities.

CASE PRESENTATION

We report a case of a 60 year old male with giant hepatic hydatid disease who presented with a huge cystic mass in the upper abdomen. Diagnosis was confirmed by serology, ultrasonography and CT scan. The patient was treated successfully by open minimally invasive surgery with minimum breaching of the peritoneal cavity using a laparoscopic trocar to evacuate the cyst.

CONCLUSION

The use of a laparoscopic trocar through a small abdominal incision in selected patients with hepatic hydatid disease with subfascial extension can be a safe, minimally-invasive option of treatment.

Imaging of Parasitic Diseases of the Thorax

A broad spectrum of parasitic infections frequently affects the lungs, mediastinum, and thoracic wall, manifesting with abnormal imaging findings that often make diagnosis challenging. Although most of these infections result in nonspecific abnormalities, familiarity with their imaging features and the diagnostic pathways help the radiologist to formulate an adequate differential diagnosis and to guide diagnosticians in reaching a definitive diagnosis.

Laparoscopic surgical techniques in patients with hepatic hydatid cyst

OBJECTIVE

The aim of this study was to describe in detail the laparoscopic treatment of patients with liver hydatid cyst.

METHOD

Seventy-six consecutive patients with 104 liver hydatid cysts were considered for laparoscopic treatment from October 2000 to October 2005.

RESULTS

A laparoscopic surgical technique was used in all cases. The method involved treatment of the residual pericystic cavity and removal of the contents of the cyst. The operating time (mean +/- SD) was 81 +/- 9 minutes (range 40-120). Complications were observed in 5 patients (6.58%) after surgery. Sixty-eight patients (89.47%) were followed-up for a mean of 14 months (range 6-38). No recurrence was found in any of the cases. The mean postoperative hospital stay was 7.6 +/- 1.0 days (range 6-15).

CONCLUSIONS

This laparoscopic hepatic hydatid surgical technique is a safe and effective method of treatment in selected patients. It can be a useful alternative for treating patients with liver hydatidosis.

Spinal hydatidosis accompanied by a secondary infection. Case report

Spinal hydatid disease is rarely encountered in nonendemic regions. It is a progressive disease that is associated with risks of serious morbidity. The authors report a case of an isolated primary hydatid cyst of the spine in a 34-year-old woman who presented with back pain, which had lasted for 3 months, as well as lower-extremity pain and fatigue, which had persisted for 2 months. A neurological examination yielded findings indicative of upper motor neuron involvement with complete sensory loss below the level of T-11. Magnetic resonance imaging of the spine showed multiple extradural cystic lesions with an abscess formation at T-11 and involvement of the paraspinal muscles. The patient underwent spinal decompression in which stabilization and total excision of the multiple epidural and psoas abscesses and paraspinal multiloculated cysts were performed. The diagnosis of hydatid disease associated with another infection was confirmed by histopathological evaluation. Albendazole was administered during the postoperative period. Previous reports of secondary infections accompanying this disease in extraspinal locations have been published. However, to the best of the authors' knowledge, there have been no publications about a secondary infection associated with hydatidosis in the spinal cord. One should bear in mind that spinal hydatidosis may be accompanied by other infections in endemic regions. Antihelminthic treatment should be administered for a long period following early decompressive surgery and adequate stabilization.

Prevention and control of cystic echinococcosis

Human cystic echinococcosis (hydatid disease) continues to be a substantial cause of morbidity and mortality in many parts of the world. Elimination is difficult to obtain and it is estimated that, using current control options, achieving such a goal will take around 20 years of sustained efforts. Since the introduction of current (and past) hydatid control campaigns, there have been clear technological improvements made in the diagnosis and treatment of human and animal cystic echinococcosis, the diagnosis of canine echinococcosis, and the genetic characterisation of strains and vaccination against Echinococcus granulosus in animals. Incorporation of these new measures could increase the efficiency of hydatid control programmes, potentially reducing the time required to achieve effective prevention of disease transmission to as little as 5-10 years.

Percutaneous treatment of univesicular versus multivesicular hepatic hydatid cysts

BACKGROUND

Percutaneous drainage has been used successfully to treat hepatic hydatid cysts. This study aimed to analyze the results of this method in the treatment of univesicular and multivesicular hepatic hydatid cysts.

METHODS

Ultrasound-guided percutaneous drainage was used to treat 72 patients (44 women and 28 men; average age, 46.8 +/- 17.7 years) with hepatic hydatidosis. Of these 72 patients, 57 had one cyst, 7 had two cysts, and 8 had three cysts. Albendazole (10 mg per kg of body weight daily for 8 weeks) was administered to all the patients. Serial assessments included clinical and biochemical examinations, ultrasonography, and serologic tests for echinococcal antibody titers.

RESULTS

During the follow-up period, the mean cyst diameter decreased from 83.3 +/- 38.6 mm to 11.1 +/- 16.0 mm (p < 0.001) in the multivesicular group (27 cysts) and from 65.5 +/- 27.5 to 5.9 +/- 13.0 mm (p < 0.001) in the univesicular group (68 cysts). The final cyst diameter did not differ significantly between the two groups (p = 0.1). The findings showed that 81% of the cysts in the univesicular group and 63% in the multivesicular group disappeared (p = 0.12). The mean hospital stay was 4.8 +/- 2.9 days in the univesicular group and 6.1 +/- 4.7 days in the multivesicular group (p < 0.001). After an initial rise, the echinococcal-antibody titers fell progressively, and at the last follow-up evaluation were negative (<1:160) for 43 patients (94%) in the univesicular group and 19 patients (73%) in the multivesicular group (p = 0.03). Mild nonfatal complications were experienced by 24 patients (33%).

CONCLUSIONS

Percutaneous drainage combined with albendazole therapy is an effective and safe method for managing hydatid cysts of the liver that requires a short hospital stay. Disappearance of the cysts depends on cyst size. Multivesicular cysts have a more complicated course, a slower disappearance, and a higher incidence of positive echinococcal-antibody titers. Abscess formed after the procedure can be treated successfully by percutaneous drainage.

Hydatid cysts: does every picture tell a story?

Ultrasound imaging is an effective aid to the detection of abdominal cystic echinococcosis. Recently, the images produced have provided more information than just a diagnosis. Different cyst morphologies have been classified into types, and such classifications can be considered to represent a natural history of cyst development. Understanding how cyst structures alter with time is crucial to evaluating the effectiveness of different treatment regimes and to understanding natural degeneration of cysts that can occur. However, the developmental events seen in ultrasound need to be matched more closely to immunological and cellular events if we are to have a fuller appreciation of disease progression and regression. At a community level, the relative proportions of cyst types could also provide epidemiological information on disease transmission.

Radiologic management of cysts in the abdomen and pelvis

OBJECTIVE

Few abdominal or pelvic cystic lesions come to the attention of the interventional radiologist, and those that do are symptomatic. Differentiation of cysts from cystic-appearing masses is not difficult when a multitechnique imaging approach is used. Our objective is to summarize the principles and specifics for management of symptomatic cysts through percutaneous catheter techniques.

CONCLUSION

Percutaneous aspiration of cysts can relieve symptoms without the need for surgery. A sound knowledge of the various types of cysts that may be found in the abdomen and pelvis enables the radiologist to select those patients who will benefit the most from percutaneous management.

Modified pair technique for treatment of hydatid cysts in the spleen

The aim of this study was to evaluate the results of single-session sclerotherapy with mixture of alcohol and polidocanol and a subsequent injection of albendazole for devisceration of hydatid cysts in the spleen. Eight patients (four women and four men, average age 22.9+/-11.4 with hydatid cyst in the spleen were treated with 10 minutes time of exposure to mixture of ethanol 95% and polidocanol 1%. After that, 2 to 5 ml of albendazole was injected into the cyst cavity. Two patients had 2 cysts. At follow-up the patients were examined with clinical and biochemical examinations, ultrasonography, and serologic test for echinococcal antibody titres. The mean hospital stay was 2.5+/-0.93 days. During the follow-up period, mean cyst diameter decreased from 46+/-16.4 mm to 13.6+/-16.26 mm. In all ten cysts, a reduction of post procedural recolection of fluid over 40% was observed. Five cysts (50%) disappeared during the follow-up period. All cysts (5) smaller then 50 mm in diameter disappeared during follow-up period. After an initial rise, the echinococcal-antibody titres fell progressively and at the last follow-up were negative (< 1: 160) in 7 (88%) patients. No complications were observed, except for pain, fever and urticaria during the first 24-hours after the procedure. Sclerotherapy using only one session and 10 min time of exposure to the mixture of ethanol and polidocanol, and a subsequent injection of albendasole solution represents an effective treatment of hydatid cysts in the spleen. This procedure is even more efficacious for hydatid cyst with diametar smaller then 50 mm.

In vitro effects of flubendazole on Echinococcus granulosus protoscoleces

The aim of the present work was to determine the in vitro protoscolicidal effect of flubendazole (FLBZ) against Echinococcus granulosus. Protoscoleces of E. granulosus were incubated with FLBZ at concentrations of 10, 5 and 1 microg/ml. The first signs of FLBZ-induced damage were observed 3 days post-incubation. A clear protoscolicidal effect, reducing the vitality of protoscoleces to 35.6+/-0.7%, was observed after 18 days of incubation. After 25 days of FLBZ incubation (5 microg/ml), the percentage of vital protoscoleces was 13.9+/-5.9%. Protoscolex mortality was 100% (10 and 1 microg/ml) and 0.7+/-0.7% (5 microg/ml) after FLBZ incubation for 30 days. Results of vitality tests were consistent with the tissue damage observed at the ultrastructural level. The primary site of damage was the tegument of the parasite. The morphological changes included contraction of the soma region, formation of blebs on the tegument, rostellar disorganization, loss of hooks and destruction of microtriches. The data reported in this article demonstrate a clear in vitro effect of FLBZ against E. granulosus protoscoleces.

[Complete extraction of a hydatid membrane by bronchial fibroscopy]

Pulmonary hydatid cyst is exceptional in our country. The diagnosis is generally established on the basis of imaging. Surgical treatment is indicated in most patients. We report a case of pulmonary hydatid cyst in a 74-year-old smoker (11 package-years) who presented cough with mucopurulent expectoration and occasional hemoptysis. The chest x-ray demonstrated a poorly delimited heterogeneous opacity in the upper third of the left lung which persisted after antibiotic therapy. Bronchial fibroscopy revealed a hydatid membrane in the left superior bronchus which was totally removed by aspiration. A control radiography after the fibroscopy demonstrated a clear regression of the opacity. A thoracic CT-scan was performed and revealed a residual cavity in the left upper lobe with bronchial dilatation. The indication for surgery was not retained. Treatment of pulmonary hydatid cyst by endoscopy is an exceptional event. Our exceptional case illustrates an atypical radiological presentation and the use of "therapeutic" fibroscopy.

Changing concepts in the management of liver hydatid disease

Hydatid disease is a rare entity primarily affecting the population of developing countries. The parasite shuttles between the liver and lungs. but almost any organ can be invaded, forming cysts. Septation and calcification of the cysts with a high antibody titre in the patient's serum confirm the diagnosis, although more sophisticated tests have been applied recently. Surgery constitutes the primary treatment, with a variety of techniques based on the principles of eradication and elimination of recurrence by means of spillage avoidance. Minimally invasive techniques and percutaneous drainage of the cysts are now feasible because of progress in the field. The aim of this review is to collect the experience from three different institutions and to provide practical guidelines for diagnostic and therapeutic strategies.

Medical treatment of pulmonary hydatid disease: for which child?

There have been many encouraging studies on medical treatment of pulmonary hydatid disease due to Echinococcus granulosus infection. Our aims were to demonstrate the safety and efficacy of medical treatment in pulmonary hydatid disease and to describe a pediatric population who would benefit from medical treatment, especially in respect to the diameter of the hydatid cyst. All patients were treated with mebendazole or albendazole. Treatment outcome was defined as cure, improvement or failure. Among 82 patients, 34.1% were cured, 34.1% improved and 31.8% failed. When 102 cysts were individually evaluated, 36.31% were cured, 32.4% improved and 31.3% failed. The cure and the failure rates were statistically insignificant in cysts treated with mebendazole and albendazole; however statistically significantly more cysts were improved with albendazole. The results were statistically insignificant between continuous and cyclic albendazole treatment. The mean size of successfully treated cysts was 5.3+/-3.4 cm, but "failed" for cyst with a mean size of 7.3+/-4.3 cm. There was a positive, weak and statistically significant correlation between the cyst size and treatment results. The major complication was infection. We suggest that selected pediatric patients with uncomplicated pulmonary hydatid cysts sized less than 5 cm should have a trial of medical treatment with a very close follow up.

Diagnosis and treatment of hepatic echinococcosis: an overview

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.

An unusual presentation of hydatid cyst within the soft tissues of the back: re-investigation of the undiagnosed lung opacity

BACKGROUND

Echinococcosis is a zoonotic infection, affecting humans in a characteristic geographic distribution. The disease most commonly involves the liver and the lung and a soft tissue localization is very rare.

METHODS

A case of a 68-year-old man, who presented with a cystic lesion on his back, which was presumed to be a lipoma or a sebaceous cyst. Surgical excision of the lesion was performed.

RESULTS

Histopathology revealed a hydatid cyst and with further investigations, we identified the nature of a previously undiagnosed opacity in the right lung field. Although the patient previously presented with symptoms of hydatid cyst rupture (productive cough with haemoptysis), echinococcosis was not under consideration.

CONCLUSIONS

This unusual case serves to demonstrate that echinococcosis, though rare, should be considered in the differential diagnosis of cystic lesions in every anatomic location, especially when they occur in endemic areas. We overview the diagnosis and treatment of this parasitic infection.

Dual treatment of albendazole in hepatic hydatidosis: New therapeutic modality in 52 cases

BACKGROUND

Hepatic hydatidosis still remains as a serious problem in general surgery. Recurrence and/or secondary hydatidosis rates are up to 25% in the cases treated with surgery alone. Albendazole is the most commonly used drug in the medical treatment of echinococcosis. The aim of the present study was to evaluate the effect of albendazole using the intraoperative and perioperative periods as dual therapy.

METHODS

Fifty-two cases of hepatic hydatidosis were evaluated and treated by dual treatment of albendazole together with surgery. Perioperative albendazole treatment was given in a dose of 12-15 mg/kg per day in four divided doses. The treatment started 2-28 days before the surgery when the diagnosis was established and continued for 2-24 months (4.76 +/- 3.25) postoperatively in a cyclic monthly form. A total of 1.7 microg/mL albendazole solution was used as a protoscolicidal agent in the cystic cavity intraoperatively. In the postoperative period serology, ultrasonography and computed tomography evaluations were done. The follow-up period was 5-92 months (mean: 62.48 months).

RESULTS

There was no recurrence in the present study. One patient died in the 6th postoperative week due to cerebral hydatidosis and multiple organ failure. Early and late morbidity rates were 7.69 and 9.61%, respectively.

CONCLUSIONS

Dual albendazole treatment is effective in the prevention of recurrences and/or secondary hydatidosis.

[Hydatid cyst of the kidney]

Hydatidosis is an endemic disease caused by the larval form of Echinococcus Granulosus. Renal involvement represents less than 5% of confirmed cases. It remains clinically silent for a long time, and only presents at the stage of complications. Diagnosis is suspected on the basis of epidemiological, clinical, radiological and biological data. There are various clinical presentations. Hydaturia, which is observed in 10 to 30% of the cases, is the only pathognomonic feature. Diagnostic accuracy has been improved since the wide use of ultrasonography. Computed tomography and magnetic resonance imaging are helpful tools to confirm the diagnosis. The treatment is mainly based on surgery. The resection of the prominent dome remains the standard option as it allows preservation of the kidney. Total nephrectomy should be proposed only in case of renal destruction. The percutaneous management, which includes puncture, aspiration, injection, and reaspiration, can be performed in very selected cases. However, the results of this technique are still under debate.

Effect of treatment with free and liposomized albendazole on selected immunological parameters and cyst growth in mice infected with Echinococcus multilocularis

Selected immunological parameters in healthy mice and mice infected with Echinococcus multilocularis and the effect of free and liposomized albendazole (lip.ABZ) upon these parameters in relation to the reduction of parasite growth were investigated over 26 weeks. Proliferative response of splenic T and B lymphocytes, number of CD4+ and CD8+ spleen T cell subpopulations, serum concentration of IFN-gamma and IL-5, and generation of superoxide anion (O2-) by peritoneal macrophages were the chosen parameters. Both drug forms were given to mice at a dose of 10 mg kg(-1) twice a week from week 4 to week 10 post infection (p.i.) (6 weeks in total). The reduction of cyst growth after treatment with ABZ and lip.ABZ was similar up to week 4 after last dose, but the parasitostatic effect of lip.ABZ lasted 4 weeks longer than the effect of free drug. After administration of both drug forms, the proliferative responses of T and B cells were restored, and also the number of CD4+ and CD8+ increased markedly. In lip.ABZ-treated mice, stimulation of mentioned lymphocyte parameters, except that of CD8+ numbers, persisted for longer period than after ABZ therapy, where values peaked at week 12 p.i., then declined more rapidly. A very strong stimulatory effect was seen on B lymphocytes during the period of lip.ABZ administration, although interestingly, numbers of CD8+ cells were higher in free ABZ-treated group. Low concentrations of IFN-gamma (Th1 response) were present in infected, untreated mouse serum. Only moderate IFN-gamma elevation was observed after treatment with free ABZ. A profound increase of its concentration was seen shortly after administration of lip.ABZ, and persisted until the experiment ended. In infected untreated mice, concentration of IL-5 (Th2 response) was highest on week 2 p.i. Significantly more IL-5 was recorded in serum of mice treated with free ABZ treatment than with lip.ABZ from week 12 to 18 p.i. (weeks 2-8 after the last dose). After the initial increase of superoxide anions (weeks 4-11 p.i.), generation of O2- by peritoneal macrophages was gradually inhibited by E. multilcoularis infection. In general, treatment abolished this suppression and macrophages from lip.ABZ-treated mice produced elevated amounts of O2- over a longer period than macrophages from ABZ-treated mice. Our data indicate that anthelmintic potency of ABZ could be increased after incorporation into liposomes, not only because of improved pharmacokinetics and consequent bioavailability, but also because of significant stimulation of Th1-type cytokine IFN-gamma response and effector macrophage functions.

Recurrent spinal hydatidosis in North America

Spinal hydatidosis is an uncommon manifestation of the parasite Echinococcus, affecting fewer than 1% of patients with hydatid disease. The authors report on a 34-year-old Turkish woman who presented with recurrent primary spinal hydatid disease. The patient originally presented with progressive numbness and paraparesis that was reversed after T5–6 laminectomy and cyst removal. Pathological findings indicated parasitic infection and she underwent treatment for cysticercosis. Nevertheless, she returned 4 years later with back pain, numbness, and monoparesis. Neuroimaging studies revealed spinal cord compression with multiple cysts that were again resected. Pathological findings were consistent with Echinococcus.

Although this disease is uncommon, particularly in North America, the authors conclude that spinal hydatidosis should be considered in the differential diagnosis of any patient who has lived or traveled within endemic areas and who presents with spine lesions and cord compression. The authors review the literature pertaining to the epidemiological features, presentation, diagnosis, neuroimaging characteristics, recommended treatments, and overall prognosis of spinal hydatidosis.

Treatment of uncomplicated hydatid cyst of the liver by closed marsupialization and fibrin glue obliteration

Treatment of hepatic echinococcosis remains a surgical problem not only in endemic countries. Between January 1983 and December 1999 a total of 29 patients underwent surgical treatment for hepatic hydatidosis at the Department of General Surgery at the University Hospital of Granada. The diagnosis was based on clinical criteria, serology, and imaging techniques. There were 16 male and 12 female patients (ages 7-67 and 30-74 years, respectively). Concomitant extrahepatic complications were found in seven patients. Among them, five had secondary parasitic cysts in the peritoneal cavity. In one case an intrathoracic rupture was found, and one patient suffered an intraabdominal rupture with anaphylactic shock. The right lobe was affected in 62% (18 patients). Hepatic cysts were multiple in 4 cases and calcified in 13. Conservative surgical procedures were performed in 23 patients (closed marsupialization with fibrin glue obliteration in 17 and drainage-marsupialization in 6), and radical surgical procedures were undertaken in 6 (pericystectomy in 5 and hemihepatectomy in 1). One patient underwent an explorative laparotomy with intraabdominal lavage followed by pericystectomy after primary resuscitation due to anaphylactic shock. The mean period of hospitalization was 15.9 days, and there were no serious postoperative complications or fatal outcomes. The perioperative morbidity rate was 2.5%. One patient suffered a recurrence of the disease following drainage marsupialization after an interval of 5 years. Our results indicate that the closed marsupialization technique is a safe, sparing method for treating uncomplicated hepatic hydatidosis. The results were also compared to those of a former study reported by our group in which the experience of another 19 years was presented.

Echinococcus granulosus infection: clinical presentation, medical treatment and outcome

BACKGROUND

Chemotherapy of cystic echinococcosis became a treatment option 25 years ago, when new anthelminthic drugs were introduced. Benzimidazole carbamates were shown to kill the entire metacestode stage of the parasite, and praziquantel exhibited an effect on protoscoleces. Continuous or intermittent treatment with albendazole is recommended for a period of up to 6 months, and praziquantel may enhance the effect, in particular in the case of cyst spillage. Degenerative changes in the cysts occur in approximately 75% of the patients by the end of the treatment period. Benzimidazoles have to be applied in high daily doses, and adverse effects are observed, such as leucopenia, elevation of liver transaminases, and alopecia. Unfortunately, prospective randomized trials on the efficacy of chemotherapy versus surgery are not available. New treatment methods, such as percutaneous puncture, aspiration, injection of scolicidal agents and re-aspiration (PAIR) or modified PAIR-based techniques, have received much attention, and in experienced hands these approaches yield rates of cure and relapse equivalent to those following surgery. Adjunct treatment with benzimidazoles is the cornerstone of the interdisciplinary approach in cystic echinococcosis.

CONCLUSION

The recent ultrasound WHO consensus classification of hepatic cysts is a major achievement, since on the basis of this classification prospective clinical trials can be initiated. The results of such studies may provide the basis for a stage-specific appropriate medical, interventional or surgical therapy, or even guide the clinicians to opt for 'watch and wait' by close observation without specific treatment.

Retrospective surgical incidence and case distribution of cystic echinococcosis in Jordan between 1994 and 2000

A retrospective follow-up study on the surgical incidence of cystic echinococcosis (CE) was carried out in major governmental, military and private hospitals throughout Jordan between 1994 and 2000. A total of 472 cases were recorded over the 7-year period and an overall mean annual surgical incidence (MASI) of 2.3 per 100,000 inhabitants was estimated. The highest number of surgical cases was recorded in hospitals of the middle region of the country. The highest MASI (3.6 per 100,000) was found in the southern region while the lowest (1.4 per 100,000) was in the northern region of the country. Taking into consideration the population size and the origin of surgically confirmed cases of each region, a relative surgical index (RSI) was calculated at which the highest (RSI=3.4) was among cases originated from the southern region and the lowest (RSI=0.7) was among those originated from the middle region of Jordan. The northern region and desert areas (badia) showed comparable RSI at 1.0 and 1.1, respectively. Males younger than 15 years of age showed significantly higher surgical incidence than females of comparable age at a ratio of 1.6:1, whereas the number of female cases of different age groups over 15 years of age was consistently higher than that of males at a ratio of 1.25-2.5:1.0. The liver was the primary site of cyst development in 69.4% of the cases and the lung involvement accounted for 13.3% of the cases. Diagnosis of CE in Jordan relies mostly on imaging methods with serological techniques being rarely used for diagnosis. The frequency of CE recurrence was 27.5% of the cases, which may be attributed to the low use of chemotherapeutic antihelminthics among surgically treated cases.

Control of echinococcosis and cysticercosis: a public health challenge to international cooperation in China

Echinococcosis, both cystic and alveolar, and Taenia solium cysticercosis are the most serious zoonotic cestodoses worldwide. Because of the emerging importance of these diseases in China, several international workshops and meetings were held in this country from 1998 to 2001. Based on round table discussions in Chengdu 2000, the proposal of a strategy to control echinococcosis and cysticercosis has been prepared in China. It includes a comprehensive approach based on a careful analysis of the local situations (particularly concerning the particularities of the cycle, ecology, and ethology of the animal hosts, and behavioral characteristics of the population at risk), the use of newly developed tools both in animals and human (immunology, molecular biology, and imaging), and the association of the traditional control measures (control of slaughtering, antiparasitic treatment and control of the definitive hosts, and health education) with more recent developments such as vaccination of the intermediate hosts. Plans on for the control of echinococcosis and cysticercosis in China are summarized.

Echinococcosis granulosus/cysticus of the tibia

Hydatid disease is caused by the parasitic tapeworm Echinococcus. There are three species: E. granulosus, E. alveolaris and E. voegeli. Only E. alveolaris and E. granulosus are important for human infections. These two species are totally divergent in their manner of infestation. Hydatid disease is a rare parasitic disease that primary involves the liver and the lung. Skeletal disease is rare, accounting for less than 2% of all hydatid lesions, and often presents as a clinical and radiologic diagnostic problem. The skeletal involvement is usually due to secondary extension after haematogenous spread of the infection. The vertebral column, the pelvis and the skull are most commonly involved. Treatment is also difficult because of the invasive nature of bony involvement and the spillage of fluid with subsequent contamination seeding. We present a case of primary hyatid cyst of the tibia. We point out the importance of considering osseous hydatidosis in the differential diagnosis of destructive bone lesions and the necessity of radical resection.

Albendazole for the treatment of echinococcosis

Twenty years after the first cases of echinococcal disease were treated with albendazole, it has become an important component in the overall management of both cystic and alveolar echinococcosis. This paper reviews some of the key steps and issues facing those who work in clinical research and who deal on a day-to-day basis with echinococcal disease. In many situations, chemotherapy alone is sufficient, but it is also used as an adjunct to surgery and to minimally invasive approaches to cyst management. While treatment may not be as effective as hoped, attempts to provide new regimens are progressing to increase cure rates further. There is now a greater understanding of the limitations of all approaches, and treatment guidelines as developed by the World Health Organization are now widely followed. As diagnostic tools are ever more widely available, the question as to who should be treated in endemic communities has to be answered.

Classification, follow-up and recurrence of hepatic cystic echinococcosis using ultrasound images

Ultrasound image and morphological structure of hepatic cystic echinococcosis (CE) were analysed in 277 human cases (385 hepatic hydatid cysts). These included 65 CE cases from community surveys carried out between 1995 and 2000 in 3 countries (China, Mongolia and Jordan) and 212 cases from a clinical hospital survey from Xinjiang, China. A new simplified WHO ultrasound classification for human CE was assessed, and considered useful. It is proposed that type, size and number in particular need to be included in the ultrasound classification of hepatic CE. For comparative purposes 6 categories of type were classified in the study as Type 0 to Type 5 (T0-T5): T0, univesicular without pathognomonic signs; T1, univesicular with pathognomonic signs; T2, cysts with sagging or floating laminated membrane; T3, cysts containing daughter cysts; T4, solid mass or mixed cysts; and T5, cysts with partial or full calcifications. This differs from the WHO classification wherein Type T3 cysts (daughter cysts present) are considered a pathological stage to occur in general prior to the sagging or floating membrane (T2) stage. Recurrent hydatid cysts in the liver were also studied based on morphological structures observed directly from surgical intervention. Case follow-up over 1-5 years since endocystectomy in the community surveys indicated 10% (2/10) recurrence of cysts in the residual surgical cavity. Recurrent CE included 2 (2/4) cases after percutaneous treatment.

International classification of ultrasound images in cystic echinococcosis for application in clinical and field epidemiological settings

The increased knowledge of the natural history of cystic echinococcosis (CE) by the recent expansion in the use of ultrasound (US) in field and clinical studies has necessitated the development of a new WHO standardised classification of US images. Use of such a classification will enable clinicians to examine recommended clinical procedures for the different cyst types. It will also allow scientists to compare data on the occurrence of cyst types in different parts of the world providing evidence to examine strain differences in the causative organism Echinococcus granulosus. The classification proposed follows that of the first classification developed by Gharbi et al. [Radiology 139 (1981) 459] which has been widely used, but in modified forms, since its publication. The classification presented here is intended for use in field epidemiological studies as well as for clinical investigators. The classification is intended to follow the natural history of CE and starts with undifferentiated simple cysts, as presumably hydatid cysts evolve from these structures. These simple cysts, however, may be due to a number of different aetiologies (parasitic lesions, congenital disorders, biliary cysts or neoplasms) and, therefore, require further diagnostic tests to reveal their identity. As their origin is uncertain they are not given the designation of a CE type lesion, and, in the proposed classification, should be recorded as cystic lesions (CL). The first clinical group starts with cyst types CE 1 and 2 and such cysts are active, usually fertile cysts containing viable protoscoleces. CE Type 3 are cysts entering a transitional stage where the integrity of the cyst has been compromised either by the host or by chemotherapy and this transitional stage is assigned to the second clinical group. The third clinical group comprises CE Types 4 and 5 which are inactive cysts which have normally lost their fertility and are degenerative. The use of the standardised US classification will facilitate the application of uniform standards and principles of treatment currently recommended for each cyst type.