Clinical Features:
Echinococcus granulosus infections remain silent for years before the enlarging cysts cause symptoms in the affected organs.  Hepatic involvement can result in abdominal pain, a mass in the hepatic area, and biliary duct obstruction.  Pulmonary involvement can produce chest pain, cough, and hemoptysis.  Rupture of the cysts can produce fever, urticaria, eosinophilia, and anaphylactic shock, as well as cyst dissemination.  In addition to the liver and lungs, other organs (brain, bone, heart) can also be involved, with resulting symptoms.  Echinococcus multilocularis affects the liver as a slow growing, destructive tumor, with abdominal pain, biliary obstruction, and occasionally metastatic lesions into the lungs and brain.  Echinococcus vogeli affects mainly the liver, where it acts as a slow growing tumor; secondary cystic development is common.

Laboratory Diagnosis:
The diagnosis of echinococcosis relies mainly on findings by ultrasonography and/or other imaging techniques supported by positive serologic tests.  In seronegative patients with hepatic image findings compatible with echinococcosis, ultrasound guided fine needle biopsy may be useful for confirmation of diagnosis; during such procedures precautions must be taken to control allergic reactions or prevent secondary recurrence in the event of leakage of hydatid fluid or protoscolices.

Diagnostic findings

• Microscopy
• Antibody detection

Treatment:
Surgery is the most common form of treatment for echinococcosis, although removal of the parasite mass is not usually 100% effective.  After surgery, medication may be necessary to keep the cyst from recurring.  The drug of choice for treatment echinococcosis is albendazole (Echinococcus granulosus).  Some reports have suggested the use of albendazole or mebendazole for Echinococcus multilocularis infections.  For additional information, see the recommendations in The Medical Letter (Drugs for Parasitic Infections).