Hydatid diseaseDr B D SoniSIDSS, SDMH

HEADS

• Introduction & epidemiology • Life cycle of hydatid worm• Pathogenesis • Clinical features• Diagnosis & imaging • Treatment

introduction

• Hippocrates recognized human hydatid over 2,000 years ago. The Arab physician, Al Rhazes, made reference to hydatid disease of the liver in AD 900

• Zoonosis- Cestodes(platihelmithies) E. granulosus, E. multilocularis, Rarely E. oligarthus

and E. vogeli

• E. granulosus, produce unilocular cystic lesions, prevalent in China, central Asia, the Middle East, the Mediterranean region, eastern Africa, and parts of South America

• E. multilocularis, which causes multilocular alveolar lesions that are locally invasive, is found in Alpine, sub-Arctic, or Arctic regions, including Canada, the United States, and central and northern Europe

• E. vogeli causes polycystic hydatid disease and is found only in Central and South America

• Both intermediate and definitive hosts

• Definitive hosts are canines (Dogs)

• intermediate hosts—sheep, cattle, goats, camels, and horses for E. granulosus, Red Fox, Mice and other rodents for E. multilocularis

• Human is accidental intermediate hosts (dead end)

• Hepatic hydatid commonly involves right lobe of liver (66%)

• Most common segment- segment VII (27%)

• Both lobes 16% and only left lobe 17%

Life cycle

Pathogenesis

• Hematogenous dissemination occurs primarily to the liver

• Other organs may also be infected, including lung (20%), brain, and bone (20%).

• Following tissue lodgment, cestode proliferation occurs in the form of a slowly enlarging cyst.

• In 80% of affected individuals, the only manifestation of echinococcal disease is a solitary cyst in a single organ.

Pathogenesis

• A primary cyst in the liver is composed of three layers: 

1. Adventitia (pseudocyst / pericyst) – consisting of compressed liver parenchyma and fibrous tissue induced by the expanding parasitic cyst 

2. Laminated membrane (ectocyst) – is elastic white covering, easily separable from the adventitia 

3. Germinal epithelium (endocyst) – is a single layer of cells lining the inner aspects of the cyst and is the only living component, being responsible for the formation of the other layers as well as the hydatid fluid and brood capsules within the cyst

Pathogenesis

• In some primary cysts laminated membranes may eventually disintegrate and the brood capsules are freed and grow into daughter cysts.

• Sometimes the germinal Epithelium protrudes out towards the external side of the cyst, to form exogenous daughter cysts, which if left untreated may cause recurrence. 

• The Hydatid cysts are slow growing approx. 1 – 3 cm / year and remain inapparent for long time

Clinical features

• Male = female (Avg age 45 yrs)• Approx 70% located in the right liver and are solitary• Cysts are largely asymptomatic until complications

occur• Symptoms of hydatid disease may be caused by

compression, obstruction, or displacement of adjacent organs or structures

• The most common presenting symptoms are abdominal pain, dyspepsia and vomiting

• May present as obstructive Jaundice (intrahepatic biliary obstuction)

• Specially in children- chronic pain abdomen, wt loss wasting

Clinical signs

• Hepatomegaly (most common)

• Palpable RUQ mass(cystic)

• Mass with Hydatid thrill (elicited by three-finger test)

• Cachexia in children

• Camellotte sign: Following intrabiliary rupture – partial collapse of the cyst wall.

Complication

• Jaundice – due to pressure over biliary tree• Pressure on portal vein can lead to portal HTN• Rupture into biliary tree – may mimic recurrent

cholelithiasis, biliary obstruction & cholangitis (commonest 60%)

• Rupture into the peritoneal cavity – may cause potentially fatal anaphylactic reaction and disseminated intraabdominal echinococcosis

• Rupture into bowel, pleural cavity can occur.• Bacterial superinfection of a hydatid cyst can occur and

present like a pyogenic abscess

Complication

• Erosion into surrounding structures or organs may result in hematogenous dissemination such as to lung, spleen, brain, muscles, bone and rarely kidney

• Parasite may die and cyst eventually may get calcified.

• Hepatic dysfunction

• Cyst rupture may also be precipitated by minor blunt abdominal trauma

Investigation

• Routine labs – nonspecific Liver involvement may be reflected in an

elevated bilirubin or alkaline phosphatase level Leukocytosis may suggest infection of the cyst

(fever) Eosinophilia is present in 25% of all persons who are

infected Hypogammaglobinemia is present in 30%

Investigation

• Primary serological test (hydatid serology) – Detect Antigens

ELISA IHA test - 80-95% sensitivity for liver hydatid.- IHA test is the initial screening tests of choice In

cases of diagnostic uncertainty- Useful in follow-up to detect recurrence

Investigation

• Secondary serological test – Detect antibody against parasite specific antigen

- Immunodiffusion and immunoelectrophoresis demonstrate antibodies to antigen (Arc 5) and provide specific confirmation of reactivity

- Sensitivity and specificity both approximate 90%

Sbihi Y, Rmiqui A, Rodriguez-Cabezas MN, et al: Comparative sensitivity of six serological tests and diagnostic value of ELISA using purified antigen in hydatidosis. J Clin Lab Anal 15:14, 2001.

Investigation

• Plain X-ray abdomen/chest valuable for pulmonary hydatid not specific for liver hydatid

• Thin rim of calcification suggestive of an echinococcal cyst.

Investigation

• Ultrasound Abdomencurrently the primary diagnostic technique and has

diagnostic accuracy of 90% Solitary Cyst – anechoic univesicular cyst with well

defined borders and enhancement of back wall echoes in a manner similar to simple or congenital cysts. Features are suggesting a hydatid etiology include dependent debris (hydatid sand) moving freely with change in position; presence of wall calcification or localized thickening in the wall corresponding to early daughter cysts

Investigation

Separation of membranes (ultrasonic water lily sign) due to collapse of germinal layer seen as an undulating linear collection of echoes

Daughter cysts - probably the most characteristic sign with cysts within a cyst, producing a cartwheel or honeycomb cyst

Multiple cysts with normal intervening parenchyma

Complications may be evident such as echogenic cyst in infection or signs of biliary obstruction usually implying a biliary communication

Investigation

Hydatid cyst of the liver on ultrasound examination

Investigation

WHO classification 2001Useful for assessing stage of a liver hydatid on

ultrasound and to decide on appropriate management for it depending on the stage of cyst

CL CE1 CE2 CE3 CE4 CE5

Investigation

CL unilocular anechoic cystic lesion without any internal

echoes and septations

Investigation

CE1uniformly anechoic cyst

with fine echoes settled in it representing hydatid sand

Investigation

CE2- Cyst with multiple septations

giving it multivesicular appearance or rossette appearance or honey comb appearance with unilocular mother cyst

- This stage is the active stage of the cyst

Investigation

CE3– Unilocular cyst with

daughter cysts with detached laminated membranes appearing as water lily sign

– This is the transitional stage of the cyst

Investigation

CE4mixed hypo and hyperechoic

contents with absent daughter cysts, these contents give an appearance of ball of wool sign indicating the degenerative nature of the cyst

Investigation

CE5– Arch-like thick

partially or completely calcified wall

– This stage of cyst is inactive and infertile

Investigation

• CT scan Has the highest sensitivity of imaging of the cyst

(98%). It is the best mode to detect the number, size, and

location, of the cysts. It may provide clue to presence of complications

such as infection, and intrabiliary rupture. CT features include sharply marginated single or

multiple rounded cysts of fluid density (3 – 30 Hounsfield units) with a thin dense rim. It is supported by floating membrane within the cysts on CT scan.

CT scan

• Provide adequate anatomic information for planning surgical therapy

• It also allows improved definition of anatomy and relationship to biliary and vascular structures

Investigation

CT

Investigation

Investigation – MRI/ MRCP

• MRI provides excellent structural detail of hydatid cysts and is superior to CT in demonstrating alteration of the hepatic venous system

• MRCP offers the added benefit of possible preoperative diagnosis of cyst-biliary fistula

• In one series, sensitivity and specificity were reported as 78% and 100%, respectively for diagnosis of cyst-biliary communication

Hosch W, Stojkovic M, Jänisch T, et al: MR imaging for diagnosing cysto-biliary fistulas in cystic echinococcosis. Eur J Radiol 66:262, 2008

Treatment

• Various options are available –

- Drug therapy- Percutaneous interventions- Endoscopic methods- Surgical (open/lap)

Treatment

• Indications for drug therapy – Adjuvant therapy with intervention- 4 days prior to

intervention and to continue it for 1 month (albendazole) or 3 months (mebendazole) after the intervention

Inoperable cysts Multiple or multiorgan cysts Recurrent hydatids Surgically unfit patients Cysts in lungs, bone, brain, eyes

Treatment - Albendazole

• Albendazole is administered in a dose of 10 – 15 mg/kg/day in adults or a fixed dose of 400 mg twice daily

• The treatment is given in cycles of 28 days (1 cycle=28days) with two weeks treatment free periods between the cycles

• Inoperable cases - as primary treatment - 3 cycles • Pre-operatively – to reduce the risk of recurrence 6

weeks continuous treatment • Post-operatively to prevent recurrence in cases of

intraoperative cyst spillage – 3 cycles

Treatment

• Side effects of Albendazole therapy are -

mild abdominal pain, nausea, vomiting, pruritis, dizziness, alopecia, rash and headache. Occasionally leucopoenia, eosinophillia, icterus, and mild elevation in transaminase levels.  

Treatment

• Contraindications of drug therapy-

Large cysts Honeycomb cysts (with septae) Infected cysts Calcified cysts Pregnancy

Treatment

• PAIR• (Puncture – Aspiration – Injection –Reaspiration)Indications- Surgically unfit/ who refuses surgery CL, CE 1, CE 2 and CE3 Relapse cysts after surgery Infected cysts In pregnant women children less than 3 years Cysts more than 5 cm in different liver segments

Treatment

• Results and problems of PAIR –

Complication rate—10-40% Mortality rate—0.9-2.5% Fever—35% - disappears in 72 hours Anaphylaxis—0.1-0.2% Same as open surgery drugs

should be kept ready for anaphylaxis Infection—10% well controlled by antibiotics Local recurrences—4% (Repeat PAIR can be done)

Treatment

• Contraindications for PAIR

Inaccessible cysts Superficially located cysts Cysts with multiple septae—honeycomb cysts Hyperechogenic cysts Communicating cysts to bile duct Calcified cysts Cysts in the lung

HOW TO PERFORM PAIR?

• Basic Requirements:• Trained personnel • USG/CT guidence• Ultrasound equipment (portable apparatus) with a

3.5 - 5 MHz probe• Needles (lumbar puncture needles, “fine needles”,

especially for multiple daughter cysts)• Catheters for large cysts (> 5 cm)• 95 % alcohol or hypertonic (at least 15 %) saline as

protoscolicide agent

PAIR

• “Fast test” for checking the presence of bilirubin in the cystic fluid (Dipstick test)

• Optic microscope• Drugs to be used in case of allergic reactions-

anaphylaxis (epinephrine, hydrocortisone); basic resuscitation equipment

• Blood pressure measurement and intravenous catheter must be left in the forearm during the procedure, so that resuscitation can take place immediately, should the need arise

PAIR

• Done under US/CT guidance.• Under local anaesthesia cyst is punctured using a

cholangiography 22 gauge needle through thickest route/part of cyst wall.

• Cyst is entered through non-dependent wall and 50% of fluid is aspirated. All multiple/daughter cysts are aspirated.

• Radiopaque dye is injected to see if any communications are present. Scolicidal agents—15-20% hypertonic saline

is injected into the cyst. After 20 minutes reaspiration is done. A sclerosant—alcohol is injected.

• If cyst is 6 cm or more, a drainage catheter is placed for 24 hours for complete drainage and later alcohol sclerosant is injected (PAIRD)

Endoscopic treatment

• The Endoscopic management is useful in presence of intrabiliary rupture, which requires exploration and drainage of the biliary tract and also after surgery in presence of residual hydatid material (membranes and daughter cyst) left in biliary tree

• During the endoscopic exploration the biliary tree is cleared of any hydatid material with a balloon catheter or a dormia basket. The endoscopic sphinterotomy is also performed to facilitate drainage of the common bile duct.  

Surgery

• Operative goal/principles-(1) Inactivate infectious cyst contents (scolices and the

germinative membrane) (2) Prevent spillage of cyst contents (3) Evacuate all viable elements(4) Manage the residual cavity(5) Management of communication between cyst and

adjacent structures

-Debate continues regarding the extent of surgery and optimal management of the cyst cavity.

Surgery

• surgery is increasingly being replaced by other options in uncomplicated cysts,

• it maintains a central role in complicated cysts (i.e., rupture, biliary fistula, compression of vital structures, superinfection, hemorrhage), cysts at high risk of rupture, or large cysts with many daughter vesicles that are not suitable for percutaneous treatments.

Francesca Rinaldi World J Hepatol 2014 May 27; 6(5): 293-305

Surgery

• As a rule, perioperative ABZ prophylaxis, from 1 wk prior to surgery until 4 wk postoperatively, is necessary to minimize the risk of secondary echinococcosis from seeding of protoscoleces in the abdominal cavity

• Radical operations include formal anatomic resection or pericystectomy. The latter involves removal of the infected cyst, pericyst, and a margin of normal surrounding hepatic parenchyma

• More conservative procedures seek to sterilize and then evacuate cyst contents, leaving the pericyst intact.

Surgery – Things to be remembered• Isolate the area- colored mops soaked with scolicidal

agent • Aspiration of a small amount of fluid to reduce

pressure before opening it • Scolicidal agent is then instilled into the cyst• Total evacuation of infected contents

Surgery

• Management of remaining cavity Marsupilization Deroofing Omentoplasty Interoflexon Capitonage Drainage of cyst

Contraindication of surgery

• Complex or widespread affection• Advanced patient age• Pregnancy• Severe comorbidities • Multiple cysts that are difficult to access• Partially inactive or calcified liver cysts • Patient refusal of surgery

RADICAL OR CONSERVATIVE SURGICALTREATMENT?

• A comparative retrospective study of 242 patients described significantly higher morbidity and recurrence rates in patients who underwent conservative surgery (11% vs 3%; 24% vs 3%)

Aydin et al , J Gastroenterol 2008• Randomized study involving 32 patients, compared

radical surgery and conservative surgery. The authors concluded that conservative surgery leads to a significantly higher early recurrence rate (P = 0.045) compared to radical surgery, as well as a higher rate of complications in the residual cyst cavity (P = 0.011)

Yüksel O, J Gastrointest Surg 2008

?Best after conservative surgery

• According to the RCT by Dziri et al omentoplasty alone leads to fewer complications than external drainage

Dziri C, Haouet K, Fingerhut A. Treatment of hydatid cyst of the liver: where is the evidence? World J Surg 2004; 28:731-736

Is laparoscopic treatment safe?

All the studies reported have observed that a laparoscopic approach is safe for the treatment of HC, with objectively low conversion rates and no mortality cases

Isolation of operating field

Colored soaked mops

Cysto-biliary fistula

Complication –surgery

• Biliary leakage is the most frequent postoperative complication following surgery for hydatid cyst of liver. It has been reported to occur in about 50% of cases because of the small-undetected communication between the cyst and the bile ducts

  • The surgical management of hydatid disease of liver

carries a mortality rate of 0.9 to 3.6 % and recurrence up to 11.3 % within 5 years. Operations carry a progressively higher mortality – increasing from 6 % after second to 20% after third. 

Follow up

• Chemotherapy: Postoperative treatment with benzimidazoles is continued for 1 month in patients with CE who have undergone complete resection or PAIR successfully. The treatment is continued for 3-6 months for patients with resected AE, incompletely resected CE, spillage during surgery or PAIR, and metastatic lesions.

• Laboratory tests: Patients on benzimidazoles should have a CBC count and liver enzyme evaluation performed at biweekly intervals for 3 months and then every 4 weeks to monitor for toxicity. ELISA or indirect hemagglutination tests are usually performed at 3-, 6-, 12-, and 24-month intervals as screening for recurrence of resected disease or aggravation of existing disease.

• Imaging: Ultrasonography and/or CT scan are used in follow-up at the same intervals as the laboratory tests or as clinically indicated.

Take home messege

• Antihelminthics serve as an important adjunct to surgical or percutaneous therapies.Preoperative albendazole is recommended by WHO as it reduces the proportion of viable scolices at operation and cuts postoperative recurrence rates by more than 50%

• Radical surgery is a better option than conservative treatment ( LOE 2b, Rec class B)

• Omentoplasty associated with conservative surgical treatment is effective in preventing postoperative complications (LOE 2b, Rec class B)

• Percutaneous drainage combined with ALB therapy is a better alternative of surgery whenever indicated

• Laparoscopic surgical approach for liver HC is safe however more RCTs and prospective studies to evaluate the value of Laparoscopic procedure need to be conducted

• Antihelminthics (ALBZ) are contraindicated in pregnancy and carry the risks of elevated liver enzymes and bone marrow suppression

THANK YOU…!