HYDATID CYST

HISTORYHISTORY• Hydatid disease - Hydatid disease - one of the oldest diseases one of the oldest diseases known to mankind, is a known to mankind, is a

parasitic infestation caused by tapeworm of genus Echinococcusparasitic infestation caused by tapeworm of genus Echinococcus

• It was first described in the Talmud as a "It was first described in the Talmud as a "Bladder full of waterBladder full of water" . " .

• HippocratesHippocrates described the human hydatid disease more than two described the human hydatid disease more than two thousand years ago with a very interesting expression (thousand years ago with a very interesting expression (liver filled liver filled with waterwith water) . ) .

HydatidHydatid :: Greek for ‘drop of water’Greek for ‘drop of water’

EchinococcusEchinococcus : :

• ‘‘hedgehog berry’hedgehog berry’

• coined by Rudolphi in the first decade of the 19coined by Rudolphi in the first decade of the 19 thth

centurycentury

Genus Echinococcus Genus Echinococcus - 4 species:- 4 species:

•E. granulosus E. granulosus - commonest -cystic echinococcosis (hydatid - commonest -cystic echinococcosis (hydatid

disease) disease)

•E. multilocularis E. multilocularis - alveolar echinococcosis - the most virulent.- alveolar echinococcosis - the most virulent.

•E. vogeli & E. oligarthus E. vogeli & E. oligarthus – polycystic echinococcosis– polycystic echinococcosis

EPIDEMIOLOGYEPIDEMIOLOGY• E. granulosusE. granulosus is present virtually worldwide, more common in sheep is present virtually worldwide, more common in sheep

and cattle raising countriesand cattle raising countries

IndiaIndia- AP, Gujarat, Tamil Nadu, West Bengal, - AP, Gujarat, Tamil Nadu, West Bengal, Orissa, Bihar, Orissa, Bihar,

Punjab, Haryana, HP, UP, Punjab, Haryana, HP, UP, Kashmir, Delhi and Pondicherry.Kashmir, Delhi and Pondicherry.

• E. multilocularisE. multilocularis -Northern hemisphere, including central Europe and -Northern hemisphere, including central Europe and

the northern parts of Europe, Asia, and North America.the northern parts of Europe, Asia, and North America.

• E. vogeliE. vogeli and and E. oligarthusE. oligarthus -Central and South America.-Central and South America.

ECHINOCOCCUS GRANULOSUSECHINOCOCCUS GRANULOSUS

• Common Name: TapewormCommon Name: Tapeworm

• Also Called Hydatid WormAlso Called Hydatid Worm

• About 5mm longAbout 5mm long

• Definitive host:Definitive host: dog & other canine dog & other canine

• Intermediate host:Intermediate host: sheep, cattle, camel & human sheep, cattle, camel & human

• Infective stage:Infective stage: egg (gravid proglottid) egg (gravid proglottid)

• Sites of hydatid:Sites of hydatid: liver, lungs, abdominal cavity, spleen, kidneys, heart, liver, lungs, abdominal cavity, spleen, kidneys, heart, bones, central nervous system etcbones, central nervous system etc

• Man is a dead end hostMan is a dead end host

TRANSMISSIONTRANSMISSION

• Ingestion from contaminated grass, usually for herbivoresIngestion from contaminated grass, usually for herbivores

• Contamination caused by poor hygiene, followed by transfer Contamination caused by poor hygiene, followed by transfer

to the mouthto the mouth

• Accidental ingestion of contaminated soil, berries or Accidental ingestion of contaminated soil, berries or

vegetablesvegetables

MORPHOLOGYMORPHOLOGYAdult wormAdult worm: : 3-6 mm3-6 mm

• ScolexScolex- pyriform 300 µm, 4 suckers and a - pyriform 300 µm, 4 suckers and a protrusible rostellum with two circular rows of protrusible rostellum with two circular rows of hookletshooklets

• NeckNeck- short, thick- short, thick

• StrobilaStrobila- 3-4 proglottids usually (immature, - 3-4 proglottids usually (immature, mature and gravid)mature and gravid)

Scolex With Hooks Protoscolices

PATHOGENICITYPATHOGENICITY• Hydatid cyst Hydatid cyst represents larval formrepresents larval form

• Generally acquired during Generally acquired during childhoodchildhood..

• Gradual Gradual displacement of vital host tissuedisplacement of vital host tissue, vessels or parts of organs →, vessels or parts of organs →damage and dysfunction damage and dysfunction

• The cyst wall is formed by:The cyst wall is formed by:

Pericyst-Pericyst-

• fibrous tissue laid down by fibrous tissue laid down by host fibroblasts host fibroblasts and new blood vessels.and new blood vessels.

• merges with surrounding normal tissue.merges with surrounding normal tissue.

• Nutrition derived through this layer.Nutrition derived through this layer.

• In old cysts, it may become sclerosed or calcified and parasite may die In old cysts, it may become sclerosed or calcified and parasite may die within it.within it.

• Absent in lung, bone, muscle, sometimes brainAbsent in lung, bone, muscle, sometimes brain

Ectocyst: Ectocyst:

• Secreted Secreted by embryoby embryo

• Tough, acellular, laminated ,elastic hyaline membrane, 1 mmTough, acellular, laminated ,elastic hyaline membrane, 1 mm

• Resembles white of a hard boiled eggResembles white of a hard boiled egg

• Protects the cyst from host enzymes, bile & bacteriaProtects the cyst from host enzymes, bile & bacteria

• Non- infectiveNon- infective

Endocyst:Endocyst:

• Germinal layer, living component of the parasiteGerminal layer, living component of the parasite

• Consists of number of nuclei embedded in a protoplasmic Consists of number of nuclei embedded in a protoplasmic mass.mass.

• Gives rise to ectocyst, brood capsules and scolicesGives rise to ectocyst, brood capsules and scolices

• Secretes Secretes hydatid fluid.hydatid fluid.

Daughter cyst

Granddaugher cyst

Protoscolex

Brood capsule

Cuticle layer

Germinal layer

Brood capsule

Daughter cysts

ORGANS AFFECTEDORGANS AFFECTEDThe parasite can colonise virtually The parasite can colonise virtually every organ every organ in the bodyin the body

• Liver- 52-77% (¾ right liver)Liver- 52-77% (¾ right liver)

• Lung- 8.5-44%Lung- 8.5-44%

• Abdominal cavity- 8%Abdominal cavity- 8%

• Kidney- 7%Kidney- 7%

• Central nervous system- 0.2-2.4%Central nervous system- 0.2-2.4%

• Bone- 1-2.5%Bone- 1-2.5%

• Less common- spleen, Less common- spleen,

bladder, thyroid, prostate , heart, eye, adrenal gland, cervix, bladder, thyroid, prostate , heart, eye, adrenal gland, cervix,

fallopian tube, ovaries, breast, pancreas, subcutaneous tissuesfallopian tube, ovaries, breast, pancreas, subcutaneous tissues..

WORK UPWORK UP

• Generally, routine laboratory tests do not show specific results.Generally, routine laboratory tests do not show specific results.• In patients with rupture of the cyst in the biliary tree, In patients with rupture of the cyst in the biliary tree,

marked and marked and transient elevation of cholestatic enzyme transient elevation of cholestatic enzyme levels levels occurs, often in association withoccurs, often in association with hyperamylasemia hyperamylasemia and and eosinophiliaeosinophilia (as many as 60%). (as many as 60%).

• Indirect hemagglutination test and enzyme-linked Indirect hemagglutination test and enzyme-linked immunosorbent assay are the most widely used immunosorbent assay are the most widely used methods for detection of anti-Echinococcus antibodies methods for detection of anti-Echinococcus antibodies (immunoglobulin G [IgG]).These tests give false (immunoglobulin G [IgG]).These tests give false positive results in cases of schistosomiasis and positive results in cases of schistosomiasis and nematode infestations that is why they are not specific nematode infestations that is why they are not specific for diagnosing hydatidosis.for diagnosing hydatidosis.

MAN'S ARM SHOWING POSITIVE SKIN TEST FOR MAN'S ARM SHOWING POSITIVE SKIN TEST FOR HYDATID DISEASE HYDATID DISEASE

IMAGING STUDIES: IMAGING STUDIES:

• Plain radiographyPlain radiography

• Ultrasound examinationUltrasound examination

• CT scaningCT scaning

• MRIMRI

B-ultrasound, liverCT, brain

CT, liver X-ray, lung

MANAGEMENT OPTIONSMANAGEMENT OPTIONS

• Medical .Medical .

• Surgery.Surgery.

• PAIR. PAIR.

• Contraindications: Contraindications: Early pregnancyEarly pregnancy, , bone marrow suppressionbone marrow suppression, , chronic hepatic diseasechronic hepatic disease, , large cysts with the risk of rupturelarge cysts with the risk of rupture, , and and inactive or calcified cysts are contraindicationsinactive or calcified cysts are contraindications. A relative . A relative contraindication is bone cysts because of the significantly contraindication is bone cysts because of the significantly decreased response.decreased response.

• Outcome : Response rates in 1000 treated patients were that Outcome : Response rates in 1000 treated patients were that 30%30% had cyst disappearance ( had cyst disappearance (curecure), ), 30-50%30-50% had a decrease in had a decrease in the size of the cyst (the size of the cyst (improvementimprovement), and ), and 20-40% had no 20-40% had no changeschanges. Also, younger adults responded better than older . Also, younger adults responded better than older adults. adults.

SURGICAL MANAGEMENT SURGICAL MANAGEMENT

• Indications: Indications:

1-Large liver cysts with multiple daughter cysts; superficially 1-Large liver cysts with multiple daughter cysts; superficially

located single liver cysts that may rupture (traumatically or located single liver cysts that may rupture (traumatically or

spontaneously).spontaneously).

2-liver cysts with biliary tree communication or pressure effects 2-liver cysts with biliary tree communication or pressure effects

on vital organs or structures.on vital organs or structures.

3-infected cysts . 3-infected cysts .

4-cysts in lungs, brain, kidneys, eyes, bones .4-cysts in lungs, brain, kidneys, eyes, bones .

CHOICE OF SURGICAL CHOICE OF SURGICAL TECHNIQUETECHNIQUE::

• 1-Radical surgery (total pericystectomy or 1-Radical surgery (total pericystectomy or partial resection, if possible), partial resection, if possible),

• 2-Conservative surgery (open cystectomy), or 2-Conservative surgery (open cystectomy), or simple tube drainage for infected and simple tube drainage for infected and communicating cysts are choices for surgical communicating cysts are choices for surgical technique. The more radical the procedure, the technique. The more radical the procedure, the lower the risk of relapses but the higher the risk lower the risk of relapses but the higher the risk of complications.of complications.

• Concomitant treatment with benzimidazoles (albendazole or Concomitant treatment with benzimidazoles (albendazole or mebendazole) has been reported to reduce the risk of mebendazole) has been reported to reduce the risk of secondary echinococcosissecondary echinococcosis. Treatment is started 4 days . Treatment is started 4 days preoperatively and lasts for 1 month.preoperatively and lasts for 1 month.

COMPLICATIONS:COMPLICATIONS:

1-All the usual complications related to the surgical procedure and anesthesia1-All the usual complications related to the surgical procedure and anesthesia

2-Related to the parasite Recurrence2-Related to the parasite Recurrence

•MetastasisMetastasis

•InfectionInfection

•Spillage and seeding (secondary echinococcosis) - Allergic reaction or anaphylactic shockSpillage and seeding (secondary echinococcosis) - Allergic reaction or anaphylactic shock

3-Related to the medical treatment Hepatotoxicity3-Related to the medical treatment Hepatotoxicity

•AnemiaAnemia

•ThrombocytopeniaThrombocytopenia

•AlopeciaAlopecia

•EmbryotoxicityEmbryotoxicity

•TeratogenicityTeratogenicity..

COMPLICATIONS , CONT.COMPLICATIONS , CONT.

4-Related to PAIR4-Related to PAIR

• HemorrhageHemorrhage

•Mechanical damage to other tissueMechanical damage to other tissue

•InfectionsInfections

•Allergic reaction or anaphylactic shockAllergic reaction or anaphylactic shock

•Persistence of daughter cystsPersistence of daughter cysts

•Sudden intracystic decompression leading to biliary fistulasSudden intracystic decompression leading to biliary fistulas

5-Related to scolicidal agents - Chemical sclerosing cholangitis5-Related to scolicidal agents - Chemical sclerosing cholangitis

PREVENTIONPREVENTION

• The best way to keep dogs The best way to keep dogs from being infected is to from being infected is to prevent them from eating prevent them from eating infected feces, or infected feces, or contaminated meatcontaminated meat

• The best way to avoid The best way to avoid human infection is to avoid human infection is to avoid ingesting food or other ingesting food or other substances contaminated substances contaminated with dog feceswith dog feces

PREVENTION (CONT’D)PREVENTION (CONT’D)

• The best method is to disrupt the lifecycleThe best method is to disrupt the lifecycle

• Basic hygiene practices Basic hygiene practices

• Avoid feeding raw offal (internal organs of butchered animals) to Avoid feeding raw offal (internal organs of butchered animals) to

dogsdogs

• By doing this hydatids have been virtually eliminated in New Zealand By doing this hydatids have been virtually eliminated in New Zealand

(a once common place for this parasite)(a once common place for this parasite)

CONCLUSION: CONCLUSION:

• Many hydatid cysts remain asymptomatic, even into advanced Many hydatid cysts remain asymptomatic, even into advanced

age. Parasite load, the site, and the size of the cysts determine the age. Parasite load, the site, and the size of the cysts determine the

degree of symptoms.degree of symptoms.

• The liver is the most common organ involved, followed by the The liver is the most common organ involved, followed by the

lungs. These 2 organs account for 90% of cases of echinococcosis. lungs. These 2 organs account for 90% of cases of echinococcosis.

• Surgery remains the main Treatment of the hydatied liver disease Surgery remains the main Treatment of the hydatied liver disease

, PAIR technique still promising. , PAIR technique still promising.

• Patient education about the prevention of this zoonotic infection . Patient education about the prevention of this zoonotic infection .

QUESTIONSQUESTIONS