Infectious Disease Compendium

Echinococcus

Microbiology

Tapeworms. E. granulosus, E. multilocularis, E. vogeli.

Epidemiologic Risks

Eating dog poop. Really. Dog poop carries the tapeworm and is on the food when you eat it. E. granulosis E. multilocularis: Sheep, goats, camels, and horses. World wide distribution.

Syndromes

Hydatid cyst disease, with liver involvement > lung. Most problems are due to mass action of the cysts; sudden rupture can lead to death from anaphylaxis. Percutanous sampling of a cyst is probably much safer than a spontaneous rupture during a rugby game. As a systamatic review put it "Lethal anaphylaxis occurred in 0.03% of PT procedures, corresponding to 0.04% of treated cysts, while reversible allergic reactions complicated 1.7% of PTs, corresponding to 1.8% of treated echinococcal cysts. Analysis of the literature shows that lethal anaphylaxis related to percutaneous treatment of CE is an extremely rare event and is observed no more frequently than drug-related anaphylactic side effects."

Treatment

Asymptomatic cysts should be observed. If symptomatic, removal by someone who know what they are doing. Medical therapy (without drainage) includes albendazole (preferred) or mebendazole for prolonged periods; there are a variety of regimens. Probably not curative (about 50%).

Notes

Directions for removal of hydatid cysts, visualize the cyst, remove some fluid, and inject a cysticidal agent, hypertonic (30%) saline, iodophor, or 95% ethanol wait 30 minutes then remove all the fluid. This has been done under CT (preferred) as well as in the operating room.

ICD9 Codes (Soon to be supplanted by ICD10)

Echinococcus (infection) 122.9; granulosus 122.4; (liver 122.0; lung 122.1; orbit 122.3 [376.13]; specified site NEC 122.3); thyroid 122.2; liver NEC 122.8; granulosus 122.0; multilocularis 122.5; lung NEC 122.9; granulosus 122.1; multilocularis 122.6; multilocularis 122.7; liver 122.5; specified site NEC 122.6; orbit 122.9 ; granulosus 122.3 ; multilocularis 122.6 [376.13]; specified site NEC 122.9; granulosus 122.3; multilocularis 122.6; thyroid NEC 122.9; granulosus 122.2; multilocularis 122.6.