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

2. 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

3. 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?

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

5. 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

6. 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.

7. Life Cycle

8. 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.

9. Adult Tapeworm Body is separated into 3 sections
Scolex with nonretractable rostellum armed with double crown of hooks

10. Infective stage: Egg
Found in dog feces
Resembles Taenia eggs

11. Metacestode (cyst) Unilocular Sub spherical in shape Fluid-filled
Pulmonary cyst are commonly found in the lower lobe on the right side

12. 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

13. 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

14. 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

15. 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

16. 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

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

18. 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

19. References
Dandan, Imad MD. “Hydatid Cyst” November 22,
Brunetti, Enrico MD. “Cystic Echinococcosis” March 5, 2004

20. 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.