The Echinococcoses: Diagnosis, Clinical Management and Burden of Disease.

The echinococcoses are chronic, parasitic diseases that are acquired after ingestion of infective taeniid tapeworm eggs from certain species of the genus Echinococcus. Cystic echinococcosis (CE) occurs worldwide, whereas, alveolar echinococcosis (AE) is restricted to the northern hemisphere, and neotropical echinococcosis (NE) has only been identified in Central and South America. Clinical manifestations and disease courses vary profoundly for the different species of Echinococcus. CE presents as small to large cysts, and has commonly been referred to as 'hydatid disease', or 'hydatidosis'. A structured stage-specific approach to CE management, based on the World Health Organization (WHO) ultrasound classification of liver cysts, is now recommended. Management options include percutaneous sterilization techniques, surgery, drug treatment, a 'watch-and-wait' approach or combinations thereof. In contrast, clinical manifestations associated with AE resemble those of a 'malignant', silently-progressing liver disease, with local tissue infiltration and metastases. Structured care is important for AE management and includes WHO staging, drug therapy and long-term follow-up for at least a decade. NE presents as polycystic or unicystic disease. Clinical characteristics resemble those of AE, and management needs to be structured accordingly. However, to date, only a few hundreds of cases have been reported in the literature. The echinococcoses are often expensive and complicated to treat, and prospective clinical studies are needed to better inform case management decisions.

Hydatid cyst of the liver-criteria for the selection of appropriate treatment.

The appropriate treatment of hydatid cysts of the liver is determined by several factors, namely the patient, the cyst, the therapeutic resources and the physician. Characteristics of cysts, can be described by ultrasonography (US). Based on US images, we can classify hydatid cysts, according the evolutionary phase of the larval parasite and to choose the most appropriate therapeutic approach. US is also important to evaluate the efficacy of the treatment. Concerning the therapeutic methods, surgery had long been the only treatment available for the hydatid cyst of the liver. Beginning the 1970s benzimidazoles, Mebendazole and Albendazole, have been used for the treatment of the hydatid disease and in the early 1980s, with the development of diagnostic US, the deliberate puncture of abdominal cysts, particularly those in the liver, was evaluated this lead to puncture/aspiration, followed by injection of a scolicide which became a therapeutic method known as puncture, aspiration, injection and re-aspiration (PAIR). So, according to the cyst's characteristics based on US evaluation we can establish a therapeutic strategy: cysts type 1 and 3 may be treated by chemotherapy. Alternative treatment should be PAIR but only if the cysts cannot be treated with benzimidazoles. If there are contraindications for PAIR and chemotherapy the treatment should be surgical. Type 2 hydatid cysts can be treated by PAIR following initial treatment with benzimidazoles. If PAIR is not feasible or there is no evidence of degenerative changes after chemotherapy, surgery is indicated. Type 4 cysts are usually inactive and, in these cases, treatment is not indicated. If there is evidence that the cysts contents are still viable PAIR may be indicate. If PAIR is not possible, surgery is the method of choice. Cysts type 5 do not require treatment.