By: Dr. Kailash Makhejani

HYDATID CYST OF LIVER

Hydatid cyst (HC), or hydatidosis, is a global parasitic zoonosis

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.  

Liver hydatid disease --- zoonosis --- caused by larva of the dog tapeworm, Echinococcus granulosus, with human being acting as an accidental intermediate host. 

Introduction 

Causative agent Intermediate host Definative host Echinococcus granulosus(Cystic echonococcosis)

Sheep, Human dog

Echinococcus multilocurlaris (Alveolar echinococcosis)

Rodents ,Humans dog,fox

Etiology

Life cycle

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. 

Pathology

Echinococcosis can involve any organ

Organs affected by E granulosus are the Liver (63%) Lungs (25%) Muscles (5%) Bones (3%) Kidneys (2%) Brain (1%) Spleen (1%)

The clinical presentation of a hydatid cyst is largely asymptomatic until complications occur.

CLINICAL FEATURES 

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

The most frequent sign is hepatomegaly/palpable mass

Jaundice and fever are each present in about 8% of patients

Bacterial superinfection of a hydatid cyst can occur and present like a pyogenic abscess

Rupture of the cyst into the biliary tree

Free ruptures can result in disseminated echinococcosis and a potentially fatal anaphylactic reaction.

CLINICAL FEATURES ….. Cont….

Routine laboratory blood workup: Nonspecific

Liver involvement may be reflected in an

elevated bilirubin or alkaline phosphatase level.

Leukocytosis may suggest infection of the cyst.

Eosinophilia is present in 25% of all persons who are infected, while hypogammaglobinemia is present in 30%.

INVESTIGATIONS 

Serodiagnostic techniques

Indirect hemagglutination(IHA) test and the enzyme-linked immunosorbent assay (ELISA)

sensitivity of 80% overall (90% in hepatic echinococcosis, 40% in pulmonary echinococcosis) and are the initial screening tests of choice.

Immunodiffusion and immunoelectrophoresis demonstrate antibodies to antigen 5 and provide specific confirmation of

reactivity

The ELISA test is useful in follow-up to detect recurrence.

INVESTIGATIONS  … Cont…

Plain X-RAY Films:Findings from plain films of

the chest, abdomen, or any other involved site are nonspecific and mostly non revealing. A thin rim of calcification delineating a cyst is suggestive of an echinococcal cyst.

IMAGING TECHNIQUES 

Ultrasound: currently the primary diagnostic technique and has diagnostic accuracy of

90%.

Findings usually seen are:  a)       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.

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

c)       Daughter cysts – probably the most characteristic sign with cysts within a cyst, producing a cartwheel

or honeycomb cyst.

d)       Multiple cysts with normal intervening parenchyma (differential diagnosis are necrotic secondaries, Polycystic liver disease, abscess,

chronic hematoma and biliary cysts.

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

Hydatid cyst of the liver on ultrasound examination. Note the multiloculated appearance of the cyst due to the presence of multiple daughter cysts. Detached germinal membranes and brood capsules can be seen in the more anterior daughter cyst. This multiseptated anechoic or hypoechoic appearance on sonography is typical of a hydatid cyst.

Highly sensitive (98%)

Best to detect the number, size, and location of the cysts

Provides 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.

Computed Tomographic scan

Computed Tomographic scan

Angiography

of the liver is suggestive but due to lack of specificity and availability of lesser invasive techniques it is rarely required

It may be required in a differential diagnosis of suspected malignancy or vascular malformation

Typical features include an avascular lesion with vascular displacement and a thin peripheral halo of higher density

Direct cholangiography (Endoscopic or percutaneous)

May be required in suspected intrabiliary rupture and bile duct obstruction

ERCP is also a valuable method for detecting post-operative complications involving the biliary tree following surgical intervention. 

Other Imaging Techniques 

Radionuclide scan has largely replaced by ultrasound and CT scan. It

remains most accurate method of demonstration of a bronchobiliary fistula.

Immunoscintigraphy is an innovation using radiolabelled antibodies to

antigens in the parasite   Magnetic resonance Imaging (MRI scan)

Images show the cysts adequately, but MRI offers no real advantage over CT scan.

Other Imaging Techniques …. Cont..

The treatment of choice is surgery

Available Options:Medical Per-cutaneous Endoscopic Surgical

TREATMENT 

CHEMOTHERAPY FOR HYDATID DISEASE OF LIVER  The compounds in common clinical use are Mebendazole and Albendazole

inhibit glucose uptake by the parasite and inhibit production of ATP

Indications:

Indicated in patients with primary liver or lung cysts that are inoperable (because of location or medical condition)

Patients with cysts in 2 or more organs Peritoneal cysts

Contraindications: Early pregnancy Bone marrow suppression Chronic hepatic disease Large cysts with the risk of rupture Inactive or calcified cysts A relative contraindication is bone cysts because of the significantly decreased response.

MEDICAL TREATMENT

Mebendazole: Disadvantages are that it is poorly absorbed from the gastrointestinal tract It is no longer used in hydatid disease 

Albendazole 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 with two weeks treatment free periods

between the cycles.

The different schedules for the treatment are:  1.       Inoperable cases - as primary treatment - 3 cycles

2.       Pre-operatively – to reduce the risk of recurrence 6 weeks continuous treatment

3.       Post-operatively to prevent recurrence in cases of intraoperative cyst spillage – 3 cycles. 

Side effects of Albendazole Mild abdominal pain, nausea, vomiting, pruritis, dizziness, alopecia, rash and headache. Occasionally leucopoenia, eosinophillia, icterus, and mild elevation in transaminase

levels.  

MEDICAL TREATMENT

PAIR (Puncture, Aspiration, Injection, Re-aspiration)Proposed in 1986 by the Tunisian team that first used it

in a prospective study

Recent and minimally invasive therapeutic option, complements or replaces surgery which was long

considered as the only treatment.

If a catheter is temporarily left in the cyst after the procedure for drainage (D), the acronym PAIRD should be preferred

PERCUTANEOUS DRAINAGE OF HYDATID CYST (PAIR)

Performed using either ultrasound or CT guidance Involves aspiration of the contents via a special

cannulaFollowed by injection of a scolicidal agent for at least

15 minutesThen reaspiration of the cystic contentsThis is repeated until the return is clear The cyst is then filled with isotonic sodium chloride

solutionPerioperative treatment with a benzimidazole is

mandatory

The cysts should be larger than 5 cm in diameter

PAIR

Patients with: Non-echoic lesion ≥ 5 cm in diameter (TYPE 1)

Cysts with detachment of membranes (TYPE2) and/or with daughter cysts (TYPE 3)

Multiple cysts if accessible to puncture

Infected cysts

Also Pregnant women

Children >3 years old

Patients who fail to respond to chemotherapy alone

Patients in whom surgery is contraindicated

Patient who refuse surgery

Patients who relapse after surgery

INDICATIONS FOR PAIR

Non-cooperative patients and inaccessible or risky location of the cyst in the liver

Cyst in spine, brain and/or heart

Inactive or calcified lesion

Cysts communicating with the biliary tree

Cysts open into the abdominal cavity, bronchi and urinary tract

Contraindications for PAIR

Minimal invasiveness

Reduced risk compared with surgery

Confirmation of diagnosis

Removal of large numbers of protoscolices with the aspirated cyst fluid

Improved efficacy of chemotherapy given before and after puncture (probably because of an increased penetration of antihelminthic drugs into cysts re-filling with hydatid fluid )

Reduced hospitalization time

Cost of the puncture and chemotherapy usually less than that of surgery or chemotherapy alone

Benefits Of PAIR

Same risks as any puncture ( haemorrhage, mechanical lesions of other tissues, infections )

Anaphylactic shock or other allergic reactions

Secondary echinococcosis caused by spillage

Chemical ( sclerosing ) cholangitis if cysts communicate with the biliary tree

Sudden intracystic decompression, thus leading to biliary fistulas

Persistence of satellite daughter cysts

Systemic toxicity of alcohol or hypertonic saline in case of large cysts (total volume injected must be carefully calculated)

Risks Of PAIR:

ERCP Effective in diagnosing biliary tree involvement from the cyst

Useful in presence of intrabiliary rupture, which requires exploration and drainage of the biliary tract

Also useful in post surgerical cases with 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.  

ENDOSCOPIC MANAGEMENT OF HYDATID CYST 

Indications: Large liver cysts with multiple daughter cysts

Superficially located single liver cysts that may rupture (traumatically or spontaneously)

Liver cysts with biliary tree communication or pressure effects on vital organs or structures

Infected cysts

Contraindications: General contraindications to surgical procedures (eg, extremes of age, pregnancy, severe preexisting

medical conditions)

Multiple cysts in multiple organs

Cysts that are difficult to access

Dead cysts

Calcified cysts

Very small cysts

SURGICAL TREATMENT

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 Mortality rate of 0.9 to 3.6 %

Recurrence up to 11.3 % within 5 years

Multiple operations carry a progressively higher mortality – increasing from 6 % after second to 20% after third. 

COMPLICATIONS OF SURGERY

Chemotherapy Postoperative treatment with benzimidazoles is continued for 1 month

in patients who have undergone complete resection or PAIR successfully

Laboratory tests Patients on benzimidazoles should have a

CBC count and liver enzyme evaluation performed at biweekly intervals for 3 months

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: Ultrasound and/or CT scan are used in follow-up at the same intervals

as the laboratory tests or as clinically indicated.

FOLLOW UP

THANKS