diagnostics and treatment

diagnosis

Thanks to modern technology, there are many ways to diagnose Echinococcosis. One of the most common ways to diagnose Hydatid Disease is to look for the presence of asymptomatic cysts. Many asymptomatic cysts can be located using Ultrasound Imaging. This technique is identical to that of imaging a developing fetus. The cysts show up as sharp outlines on the ultrasound image, and occasionally fluid levels can be detected. CT and MRI scans are also useful in detecting cysts that are on the liver and/or spleen.6 

Figure 4: The picture above is an image of the upper abdominal region, with a large cyst on the liver (arrow). Courtesy of Medline Plus.8

Diagnosis of Echinococcosis can also be done through serologic tests, including Immunoblot, Indirect Hemagglutination test (IHA), and Enzyme-linked Immunosorbent Assay (ELISA). These serologic tests 80-100& effective with liver cysts, but only 50-60% effective when cysts are located on other organs. When a cyst ruptures, there is an abrupt stimulation of antibodies, but when these cysts calcify or die, they become seronegative. If the CT scan shows a cyst, a diagnosis should be made - regardless of confirmation by serology (King, 2000; Wilson & Schantz, 2000) A Casoni skin test can also be administered to diagnose hydatid disease.

Figure 5: Man's arm showing positive skin test for hydatid disease. Courtesy of CDC.

treatment

The first drug that was found to be effective against the Hydatid stage of this disease was Mebendazole. It was later found that Albendazole was more effective in treating Echinococcosis because the drug was better absorbed and penetrated well into the cyst walls. Albendazole is given orally at 10-15 mg/kg body weight per day or fixed doses of 400 mg twice a day in adults for four weeks, repeated as necessary for up to 12 cycles separated by two week intervals.9 Praziquantel is used as adjunct therapy as it only kills the inside of the hydatid cyst and not the germinal layer. It is currently being used as adjunct therapy with albendazole for pre and post-operative protection against cyst spillage. However, surgical excision of the cyst remains the treatment of choice for symptomatic cysts (Safioeas et al, 1999).10