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This is our last case of the week for 2012.  We hope you have enjoyed the 2012 series of live cases each week from Perú.  The Gorgas Diploma Course is held annually in February and March and we will be in touch at the beginning of next year’s case series.

David O. Freedman & Eduardo Gotuzzo
Course Directors

History:  40 year old female married for 14 years without conceiving; presents for further evaluation of infertility after multiple intra-abdominal cysts were discovered.  She has noted for the last three years increasing distention and deformity of the lower abdomen, but on questioning of her mother, masses had been noted even in her late teens.  Past medical history include resection of a mass in each lung as a teenager after an episode of hemoptysis. No other treatment was given at that time.  No current history of fever, weight loss, or systemic symptoms.

Epidemiology:  Born and lives in the highlands of Junín in an agricultural environment including contact with large and small animals.  No specific TB exposures.

Physical Examination:  Afebrile.  Abdomen was non-tender but distended, particularly the lower abdomen; on gentle palpation several discrete masses were felt.

Laboratory Results:  Hematocrit and WBC normal with normal differential.  AST, ALT, GGT normal.  Chest x-ray normal.  Abdominal and pelvic CT scan shows a single calcified hepatic cyst and multiple large multiseptate intra-abdominal and pelvic cysts [Images A & B].  Ultrasound (not shown) showed cysts compressing and displacing the fallopian tubes.

Discussion:  The large intraperitoneal multiseptate cysts on CT scan are diagnostic of hydatid disease.  Older involuted cysts such as the one in the liver here show a characteristic calcification pattern.  Western blot for E. granulosus was positive.  Serology is usually positive with solitary hepatic cysts but sensitivity drops below 50% with solitary pulmonary cysts even when the cyst is large.  With the large burden of disease in this patient’s liver and abdominal cavity a positive serology would be expected.  Image C shows an intact large hydatid cyst and Image D shows a gross surgical specimen from a similar case from our files.  Previous hepatic hydatid cases we have shown are Gorgas Cases 2003-03 and 2011-05.  In adults the expectoration of salty-tasting fluid with or without pieces of white membranous material is highly characteristic of a fistula or frank rupture of a cyst into a bronchus, but children may not be able to describe this.  On further questioning the patient recalled a compatible episode at the time of her episodes of hemoptysis.

Human hydatid disease secondary to Echinococcus granulosus is caused by the larval form of this dog tapeworm.  Humans ingest the tapeworm eggs in environments contaminated by canine feces and become accidental intermediate hosts.  This patient had ongoing exposure to dogs while her parents were working raising cattle and sheep.  Sheep are the normal intermediate hosts.  In general, disease is diagnosed in adulthood as larval cysts expand slowly over years or decades, becoming symptomatic as they impinge on other structures by virtue of their size.  The cysts contain hundreds of viable protoscoleces capable of becoming adult tapeworms upon ingestion by a definitive host such as the dog.  The internal germinal membrane lining the cyst produces new protoscoleces on an ongoing basis.  Each protoscolex is capable of becoming a new daughter cyst should the original cyst rupture or be ruptured.

Cystic hydatid disease due to E. granulosis is common in sheep and cattle raising areas worldwide.  Most primary infections involve a single cyst.  In adults, 65% of solitary cysts are found in liver, 25% in lung and the rest in a wide variety of other organs including kidney, spleen, heart, bone and brain.  In patients with a pulmonary cyst, approximately 18% will also have a hepatic cyst.  Bilateral lung hydatid cysts are present in 6% of adults but in up to 30% of children [Pediatr Radiol. 1978 Sep 26;7(3):164-71].  This patient had bilateral pulmonary cysts as a teenager and at some point in time it is likely that the hepatic cyst ruptured, perhaps due to incidental external trauma, and seeded the peritoneal cavity [see Gorgas Case 2012-05].

Albendazole is the therapy of choice for intact cysts that are not operable, such as when there are multiple or disseminated cysts.  A trial of continuous albendazole may also be considered for solitary cysts that are less than about 5 cm.  Response is generally slow.  Albendazole should be immediately instituted in ruptures whether they be spontaneous, post-traumatic or the result of a surgical accident.  Praziquantel is the most potent scolicidal drug and is the drug of choice for all adult tapeworms.  In hydatid disease, praziquantel is unlike albendazole and does not penetrate the cyst wall or produce measurable concentrations in cyst fluid. Praziquantel is also ineffective against the germinal membrane of cysts, but is able to reliably and quickly kill free protoscoleces [Acta Trop. 2009 Aug;111(2):95-101].  Thus, praziquantel is useful as an acute therapy when a cyst ruptures (spontaneously, or intra-operatively due to surgical mishap) and scoleces are lying free before encysting again.  A recent international consensus document [Acta Trop. 2010 Apr;114(1):1-16] also recommends routine pre-operative praziquantel/albendazole therapy for liver cysts in case of surgical spillage.  Combined praziquantel and albendazole for medical therapy of liver or lung hydatid has been reported in several small, uncontrolled series and experimental protocols examining combination therapy using are underway in several places.

Our patient has requested aggressive therapy, so the plan is for surgical debulking and resection of the cysts followed by praziquantel plus albendazole.