Liver cyst is a cavity in the liver, filled with fluid. Approximately 0.8% of the population has liver cysts. Women have this disease 3-5 times more often than men, mainly in the period between 30 and 50 years.
Echinococcus granulosus is a small tapeworm that causes the formation of hydatid cysts.
The adult worm is 2-8 mm of length and consists of a scolex with four suction cups and a rim of hooks and 3-4 body segments called proglottids. Last proglottis usually mature and contains hundreds of eggs. Each egg is approximately 30 microns in diameter. The adult worm lives in the lumen of the gastrointestinal tract of the definitive host of predators (usually dogs, foxes or cats). When proglottis breaks – matured eggs are excreted with the faeces. Humans usually get this parasite’s eggs with contaminated food or water. These larvae penetrate the intestinal mucosa from the duodenum and spread with the venous blood to the capillaries of various organs. A connective tissue begins to grow around each larva as a protective mechanism in the host organism. That’s how hydatid cyst is formed. Most often hydatid cysts affect the liver, but are also found in the spleen, lungs, heart and brain. New scolexes bud off at the inner wall of the cyst. After some time subsidiary cysts can form within the main cyst.
Where and how to get infection
You can be infected with Echinococcus granulosus in any part of the world, including Alaska, Canada, and the western states of USA. Infection mostly occurs in places where a lot of sheep and cats live. People are the intermediate hosts of Echinococcus granulosus. The worm’s eggs appear in the human body with consumption of contaminated food and water. Children often become infected if they allow dogs to lick their lips.
Hydatid cyst of the liver increases in size by 1-5 cm per year. People are often unaware of the infection as long as tumor formation in the abdomen begins to be palpable or other clinical signs appear. The symptoms of the disease are caused by the presence of slowly increasing cysts: abdominal pain due to stretching of the capsule of the liver, jaundice due to compression of the bile ducts or portal hypertension caused by compression of the portal vein. Approximately 20% of patients have cysts connected with bile duct. This can cause symptoms similar to choledocholithiasis. Breakthrough of hydatid cysts in the free abdominal cavity may provoke an immune response with eosinophilia, bronchospasm and anaphylactic shock.
The main treatment for hydatid cysts of the liver is their surgical excision. Drug therapy with albendazole in combination with percutaneous drainage of the cyst is also very effective. The drug mebendazole is also used to treat hydatid cysts.