Pulmonary EchinococcusPulmonary Echinococcus

Megan BrundrettMegan Brundrett

December 15, 2009December 15, 2009

Pathology 1Pathology 1

Pathology 2Pathology 2

EchinococcusEchinococcus

CestodesCestodes – divide their life cycle in 2 or – divide their life cycle in 2 or more hostsmore hosts

- Intermediate host – immature parasite as Intermediate host – immature parasite as a tissue cysta tissue cyst

- Definitive host – mature parasite as a Definitive host – mature parasite as a tapewormtapeworm

Echinococcus granulosusEchinococcus granulosus Echinococcus multilocularisEchinococcus multilocularis

E. granulosusE. granulosus

Hydatid diseaseHydatid disease Definitive hosts are Definitive hosts are dogsdogs or other canines or other canines Intermediate hosts – Intermediate hosts – sheepsheep, goats, , goats,

camels, horses, humanscamels, horses, humans Australia, New Zealand, Argentina, Chile, Australia, New Zealand, Argentina, Chile,

Ireland, Scotland, middle Europe, KenyaIreland, Scotland, middle Europe, Kenya

E. multilocularisE. multilocularis

Alveolar diseaseAlveolar disease Definitive host – foxes, and other caninesDefinitive host – foxes, and other canines Intermediate host – rodents, humansIntermediate host – rodents, humans Arctic areas of United States, Canada, Arctic areas of United States, Canada,

and Russiaand Russia

Life CycleLife Cycle

(1) Adult tapeworms in bowels of (1) Adult tapeworms in bowels of definitive hostdefinitive host

(2) Eggs passed in feces, (2) Eggs passed in feces,

ingested by intermediate hostingested by intermediate host (3) Onchosphere penetrates (3) Onchosphere penetrates

intestinal wall, carried via blood intestinal wall, carried via blood vessels to lodge in organsvessels to lodge in organs

(4) Hydatid cysts develop(4) Hydatid cysts develop

(5) Protoscolices (larvae) (5) Protoscolices (larvae) ingested by definitive hostingested by definitive host

(6) Attach to small intestine of (6) Attach to small intestine of

definitive host and grow to adult definitive host and grow to adult worm.worm.

Hydatid diseaseHydatid disease

E. granulosusE. granulosus 75% hepatic75% hepatic involvement, 25% involvement, 25%

pulmonarypulmonary Other organs – brain, bone, heart, kidneyOther organs – brain, bone, heart, kidney Cause symptoms with mass effect, Cause symptoms with mass effect,

rupture, secondary infectionrupture, secondary infection

Alveolar diseaseAlveolar disease

E. multilocularisE. multilocularis < 5% of symptomatic Echinococcal infections< 5% of symptomatic Echinococcal infections Lacks a limiting membrane like hydatid disease Lacks a limiting membrane like hydatid disease

and causes more infiltration to surrounding and causes more infiltration to surrounding tissues.tissues.

Clinical presentation – jaundice, RUQ pain, Clinical presentation – jaundice, RUQ pain, malaisemalaise

If untreated >90% die within 10 yearsIf untreated >90% die within 10 years Now prognosis improved b/c of albendazole Now prognosis improved b/c of albendazole

therapy. Very difficult to surgically resect.therapy. Very difficult to surgically resect.

Pulmonary Echinococcal Pulmonary Echinococcal DieaseDiease

60% right lung60% right lung 50-60% in lower lobes50-60% in lower lobes Lungs may be a more common site in Lungs may be a more common site in

childrenchildren 30% have multiple cysts in the lungs30% have multiple cysts in the lungs 20% of pts with lung involvement have 20% of pts with lung involvement have

liver involvementliver involvement

Clinical ManifestationsClinical Manifestations

Unruptured cystUnruptured cyst: Chest pain, hemoptysis, : Chest pain, hemoptysis, chronic coughchronic cough

Ruptured cystRuptured cyst: Cough, fever, expectorating : Cough, fever, expectorating salty material (hydatid membrane and larvae).salty material (hydatid membrane and larvae).

Acute hypersensitivityAcute hypersensitivity with rupture: Fever, with rupture: Fever, urticaria, sometimes anaphylaxisurticaria, sometimes anaphylaxis

Superinfection Superinfection by bacteria, fungal presenting by bacteria, fungal presenting with fever, sepsis with fever, sepsis

Pulmonary HTN, Pulmonary embolismPulmonary HTN, Pulmonary embolism

DiagnosisDiagnosis

CXRCXR: Round or oval mass with smooth : Round or oval mass with smooth borders. No calcifications. If pericyst borders. No calcifications. If pericyst (fibrous capsule that host makes) (fibrous capsule that host makes) incorporates bronchioles, than air incorporates bronchioles, than air penetrates between the pericyst and penetrates between the pericyst and exocyst creating a meniscus sign or exocyst creating a meniscus sign or crescent shape.crescent shape.

CT scanCT scan: Thin enhancing ring if cyst is : Thin enhancing ring if cyst is intact. Fluid filled in center. Homogenous.intact. Fluid filled in center. Homogenous.

CXRCXR

Differential DiagnosisDifferential Diagnosis

Primary lung cancerPrimary lung cancer Metastatic cancerMetastatic cancer TuberculosisTuberculosis Bronchogenic CystBronchogenic Cyst Round pneumoniaRound pneumonia AspergillosisAspergillosis

Laboratory DataLaboratory Data

Less than 15%Less than 15% have peripheral eosinophilia, have peripheral eosinophilia, only if leakage of antigenic materialonly if leakage of antigenic material

Immunodiagnostic testing for serum Immunodiagnostic testing for serum antibodies: + 50% for pulmonary, > 90% for antibodies: + 50% for pulmonary, > 90% for hepatichepatic

- False positive if have another parasitic infection- False positive if have another parasitic infection- More likely to have false negative if intact cyst- More likely to have false negative if intact cyst Percutaneous aspiration: Not often use in Percutaneous aspiration: Not often use in

pulmonary echinococcus, but used with pulmonary echinococcus, but used with hepatic cysts for diagnosis and treatment. hepatic cysts for diagnosis and treatment. Fluid contains hooklets, protoscolices, etc.Fluid contains hooklets, protoscolices, etc.

ManagementManagement

Surgical resectionSurgical resection: Treatment of choice: Treatment of choice- Minimize spilling of contents to prevent Minimize spilling of contents to prevent

spread, and allergic reactionspread, and allergic reaction- Intact cystIntact cyst- Cystic fluid aspiration, and scolicidal Cystic fluid aspiration, and scolicidal

solution (hypertonic saline) for solution (hypertonic saline) for deactivationdeactivation

- Recurrance rate after removal 1-3%Recurrance rate after removal 1-3%

Management 2Management 2

ChemotherapyChemotherapy: Used with poor surgical candidate, : Used with poor surgical candidate, unresectable lesion, multiple cysts, after cyst rupture, unresectable lesion, multiple cysts, after cyst rupture, or if intraoperative spillageor if intraoperative spillage

- Prior to surgery reduces tension of cystPrior to surgery reduces tension of cyst- Albendazole 400 mg PO BIDAlbendazole 400 mg PO BID- Length of treatment 3-6 monthsLength of treatment 3-6 months- No established monitoring guidelines for response of No established monitoring guidelines for response of

therapytherapy- Disappearance of cysts in 30%, decrease in size in 30-Disappearance of cysts in 30%, decrease in size in 30-

50%, no change in 20%50%, no change in 20%- 25% relapse rate, more common with multiple cysts, 25% relapse rate, more common with multiple cysts,

children and elderly adultschildren and elderly adults

PreventionPrevention

Avoiding close contacts with dogsAvoiding close contacts with dogs Careful washing of hands, and produceCareful washing of hands, and produce Prohibition of home slaughter of sheep and to Prohibition of home slaughter of sheep and to

prevent dogs from eating the infected visceraprevent dogs from eating the infected viscera Treating infected dogs with PraziquantalTreating infected dogs with Praziquantal Eliminating stray dogsEliminating stray dogs Vaccination: Appears to be 95% effective in Vaccination: Appears to be 95% effective in

animal studies, not used on humans currentlyanimal studies, not used on humans currently

ReferencesReferences

““Clinical manifestations and diagnosis of cystic and Clinical manifestations and diagnosis of cystic and alveolar echinococcosis.” alveolar echinococcosis.” UptoDateUptoDate. . 2009.<www.uptodate.com>2009.<www.uptodate.com>

Goldman, Lee et al. Goldman, Lee et al. Cecil Textbook of MedicineCecil Textbook of Medicine. . Philadephia: Saunders, 2004.Philadephia: Saunders, 2004.

Morar,R and Feldman,C. Morar,R and Feldman,C. Eur Respir J 2003Eur Respir J 2003; 21: 1069-; 21: 1069-1077.1077.

““Treatment and prevention of echinococcus.” Treatment and prevention of echinococcus.” UptoDateUptoDate. 2009.<www.uptodate.com>. 2009.<www.uptodate.com>