A Case Study about Echinococcus granulosus by Sarah Wycoff Those Dog-Gone Cysts A Case Study about Echinococcus granulosus by Sarah Wycoff

Patient History 53-year-old Middle-Eastern female Presented to the hospital Prompt Care Clinic with a severe cough and chest pains Surgeon at another hospital had removed a cyst from her lungs and liver

Questions to Consider What caused the cysts that were removed? How is this parasite transmitted to humans? How does the lab help in the diagnosis of this parasite? What is the treatment for this parasite?

Echinococcus Species 3 known species of Echinococcus are medically important Echinococcus granulosus Echinococcus multiocularis Echinococcus vogeli

Echinococcus granulosus A zoonotic infestation by a tapeworm causing hydatid disease Very rare disease in the continental US (less than 1 case per 1 million inhabitants) Endemic areas include Mediterranean counties, the Middle East, Iceland, Australia, New Zealand

Life Cycle Dogs are the definitive hosts Sheep are intermediate hosts Adult worm develops in the small intestine Eggs are voided in the feces of the dogs Sheep are intermediate hosts Humans are accidental intermediate hosts Larval form develops mainly in the liver and lungs The cycle is completed when a dog eats a cyst-infested liver or lungs.

Life Cycle

Infected Dogs Small intestine of a dog infected with Echinococcus granulosus  Adult tapeworms are small (2 mm) but they can be very numerous F. Rochette, 1999, Dog Parasites and Their Control, Janssen Animal Health, B.V.B.A.

Adult Tapeworm Body is separated into 3 sections Scolex with nonretractable rostellum armed with double crown of 28-50 hooks

Infective stage: Egg Found in dog feces Resembles Taenia eggs

Metacestode (cyst) Unilocular Sub spherical in shape Fluid-filled Pulmonary cyst are commonly found in the lower lobe on the right side http://www.biosci.ohio-state.edu/~parasite/echinococcus.html

Human Host Each egg contains an embryo (oncosphere) Eggs hatch in the human stomach and release the oncosphere The oncosphere penetrate the intestinal lining and enter the blood stream Travel to any organ, usually lung and liver, and a cyst develops

Cyst stage in Humans The cyst consists of a thick outer layer (*), several thinner internal layers, and many protoscolices. The protoscolices are often called "hydatid sand." A single protoscolex. “Hooks” can be seen that will form the hooks associated with the adult worm's rostellum http://www.biosci.ohio-state.edu/~parasite/echinococcus.html

Symptoms Vary by size and site of cyst Usually no symptoms until cyst becomes enlarged Liver: jaundice, portal hypertension, pain Lung: coughing, shortness of breath, chest pain Brain: seizures, paralysis Rupture of cyst: anaphylactic shock, spread of scolices, death

Diagnosis Radiographic images of lungs and liver Examination of sputum or bronchial washes Protoscolices Membranes Hooklets Serologic test Increase sensitivity if liver and lungs are infected

Morbidity Free rupture of echinococcal cyst (with or without anaphylaxis) Infection of the cyst Dysfunction of the affected organs Biliary obstruction Cirrhosis Bronchial obstruction Renal outflow obstruction

Treatment Surgery Drugs Risks of operative morbidity, recurrence of cyst, anaphylaxis or dissemination of the infection Drugs Albendazole, mebendazole or praziquantal

Summary Patient has hydatid disease caused by Echinococcus granulosus Patient continuing with oral treatments of albendazole Patient is seen every 3 months by her physician Periodic CT scans are performed on her chest and liver

References Dandan, Imad MD. “Hydatid Cyst” November 22, 2002. http://www.emedicine.com/med/topic1046.htm Brunetti, Enrico MD. “Cystic Echinococcosis” March 5, 2004 http://www.emedicine.com/med/topic629.htm http://www.biosci.ohiostate.edu/~parasite/echinococcus.html

Credits This case study was prepared by Sarah Wycoff, MT(ASCP) while she was a Medical Technology student in the 2004 Medical Technology Class at William Beaumont Hospital in Royal Oak, MI.