Transcript Echinococcus Granulomas

Those Dog-Gone Cysts
A Case Study about Echinococcus granulosus
by Sarah Wycoff
Patient History
53-year-old MiddleEastern 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


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

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.ht
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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.