Liver Cysts: Hydatid Flashcards
What are hydatid cysts?
Hydatid cysts, or Echinococcal cysts, result from infection by the tapeworm Echinococcus granulosus.
Briefly describe the transmission of Echinococcus granulosus
Infection by the tapeworm Echinococcus granulosus.
The eggs as passed by faceo-oral transmission. After being excreted by carnivores (commonly from dogs), the larvae invade their hosts’ gastrointestinal tract, before passing via the hepatic portal system into the liver, where they continue to grow and form cysts.
Where in the world is echinococcal disease prevalent?
Echinococcal disease has a global distribution, though the highest prevalence is in South America, North Africa and Central Asia.
What are the clinical features of hydatid cysts?
Cysts may only grow at a rate of a couple of millimetres per year. As a result, they can remain asymptomatic and undetected for many years.
The most common presenting symptom is vague abdominal pain, caused by mass effect on surrounding structures or due to rupture.
The disease can also result in jaundice or cholangitis (if the biliary system is involved), vomiting, dyspepsia and early satiety or rarely anaphylaxis if the cyst ruptures into the thorax or intraperitoneally.
What investigations should be ordered for hydatid cysts?
LFTs are often normal, unless presenting with a cholangitis picture. FBC can show an eosinophilia. Echinococcal antibody titres are positive in 80% of those with the disease.
Ultrasound scanning will reveal a calcified, spherical lesion with multiple septations. It may be anechoic or containing snowflake-like inclusions. Further assessment can be performed via CT imaging with contrast.
Why is aspiration not recommended in hydatid cysts?
Aspiration is not recommend in those with suspected hydatid cysts as rupture may cause an anaphylactic reaction. If cysts are asymptomatic and inactive, it may be possible to monitor them.
Briefly describe the treatment for hydatid cysts
The primary treatment is surgical with cyst deroofing. Radiological drainage and injection of scolecidal agent (the PAIR technique) is also an option in specialist centres.
Medical management is used as an adjunct to surgical therapy, in those with widely disseminated hydatid disease or in patients who are unfit for surgery. For patients in whom active treatment is indicated, anti-microbial action varies however a combination of albendazole, mebendazole and/or praziquantel is normally given.
