Sharing essential knowledge with health researchers and policy makers

Communities of practice

Sonographic spectrum of hydatid disease

10 Jul 2008

Paul Chinnock

Source: Ultrasound Quarterly (see original article)

Citation: Turgut AT, Akhan O, Bhatt S, Dogra VS (2008). Sonographic spectrum of hydatid disease. Ultrasound Q; 24(1):17-29

Hydatid disease (echinococcosis) is caused by the tapeworms Echinococcus granulosus, E. multilocularis and related species. It can affect many animals, including rodents, dogs, commercial livestock and humans. Tiny worm embryos lodge in such organs as the liver, lungs and/or kidneys, where they develop into much larger hydatid cysts that produce thousands of tapeworm larvae. The symptoms of the disease begin as the cysts grow bigger and start eroding and/or putting pressure on blood vessels and organs. Large cysts can also cause shock if they rupture. Some cases are fatal. Further information is available from the website of the World Health Organization (WHO).

Where ultrasound facilities are available, they play a valuable role in the diagnosis of the condition, as described in this review from a Turkish group of authors.

Note: This article is published in a journal which is not open access. To see the full article a subscription to Ultrasound Quarterly is therefore required. In some developing countries, readers who are based in institutions may be able to access it through the HINARI programme.

Abstract

Hydatid disease, caused by Echinococcus granulosus, is a parasitic disease that is endemic in many parts of the world. Hydatid cyst demonstrates a variety of imaging features, varying according to growth stage, associated complications, and affected tissue. The radiologic findings range from purely cystic lesions to a completely solid appearance. Ultrasound is the most important imaging modality for liver hydatid disease and clearly demonstrates the floating membranes, daughter cysts, and hydatid sand characteristically seen in purely cystic lesions. The radiologist’s familiarity with the imaging findings of the disease is very important for earlier diagnosis and an appropriate treatment. There are several classification schemes for liver hydatid cysts based on their ultrasound appearances; the initial classification by Gharbi et al and the World Health Organization classification are the most commonly preferred. Computed tomography and magnetic resonance imaging play a key role in recognizing the complications such as rupture and infection of cysts associated with hydatid disease. Today, percutaneous treatment of liver hydatid cysts, a safe, easily applicable, and well-tolerated method, has become the most effective and reliable treatment procedure in most cases if the hydatid cyst is viable. In patients treated with the percutaneous treatment technique, a decrease in the dimensions of the cyst, solidification of the cyst contents, and irregularity in the walls of cysts are signs suggestive of cure. The radiologist should also be familiar with the postoperative follow-up ultrasound findings of hydatid cyst to prevent misinterpretation of the hypoechoic, anechoic, or hyperechoic appearance of posttreatment hydatid disease appearance as recurrence.