abc hdat.pdf

HYDATID CYST OF LIVER
By Dr.Aakif Yousaf

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.
• Liver hydatid disease is a zoonosis caused
by caused by larva of the dog tapeworm,
Echinococcus granulosus, with man acting
as an accidental intermediate host.

Etiology
Causative agent Intermediate host Definative host
Echinococcus
granulosus
(Cystic echonococcosis)
Sheep, Human dog
Echinococcus
multilocurlaris
(Alveolar
echinococcosis)
Rodents ,Humans dog,fox

Life Cycle
• The adult form of Echinococcus granulosus resides in the small
intestine of dogs. The ova from the adult worm are shed through the
canine feces into the environment, where the intermediate host
sheep and humans ingest the eggs, in humans after entering
proximal portion of the small intestine, the larvae burrow through the
mucosa, enter the portal circulation and travel to liver. The cycle is
completed when dogs eat the carcass of animals infected with the
hydatid cysts.

Pathology
• 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. 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. 2 – 3 cm / year and
remain inapparent for long time.

CLINICAL FEATURES
• Theoretically, echinococcosis can involve any organ.
• Organs affected by E granulosus are the liver (63%), lungs (25%),
muscles (5%), bones (3%), kidneys (2%), brain (1%), and spleen
(1%).
• The clinical presentation of a hydatid cyst is largely asymptomatic
until complications occur.
• 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.

INVESTIGATIONS
• Laboratory Studies
• Routine laboratory blood workup: The results of routine
laboratory blood work are 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%.
• Serodiagnostic techniques
• Indirect hemagglutination test and the enzyme-linked
immunosorbent assay (ELISA) have a 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.

IMAGING TECHNIQUES
• 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.

• 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.

Gharbi’s Classification
• Type I : pure cystic fluid
Collection (spherical-
oval, thick-walled)
• Type II : fluid Collection
with membrane
separation
• Type III : Fluid
collection with septa
•
TypeIV: heterogeneous
(hypoechoic-
hyperechoic-
intermediate) pattern
• Type V: completely
calcified (Reflecting)
walls

Computed Tomographic 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
Fig. 3.34 Type I, II and III
unruptured hydatid cysts in 4
different patients. (A)
Univesicular uncomplicated type
I cyst in a 54-year-old man. (B)
Multivesicular type II hydatid with
multiple daughter cysts giving a
septated appearance to the cyst
in a 21-year-old woman. (C) Old
hypermature liver hydatid in a
64-year-old man. Non-contrast
CT shows calcification in the
cyst wall and matrix and fluid
within the cyst, suggesting it is
still evolving and not innocuous
and should be treated. (D) Two
hydatid liver cysts in a 75-year-
old man. The larger
pseudotumoral cyst has some
calcification in its wall while the
smaller type III cyst is totally
calcified on non-contrast CT.

Other Imaging Techniques
• 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.
• 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.

TREATMENT
• The treatment of choice is surgery.
• Available Options:
• Medical
• Per-cutaneous
• Endoscopic
• Surgical

MEDICAL TREATMENT
• CHEMOTHERAPY FOR HYDATID DISEASE OF LIVER
• The compounds in common clinical use are mebendazole and
albendazole which inhibit the uptake of glucose by the
parasite and inhibit production of adenosine triphosphate.
• Indications: Chemotherapy is 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, and peritoneal cysts.
• Contraindications: Early pregnancy, bone marrow
suppression, chronic hepatic disease, large cysts with the risk
of rupture, and inactive or calcified cysts are
contraindications. A relative contraindication is bone cysts
because of the significantly decreased response.

MEDICAL TREATMENT
• Mebendazole:Its disadvantages are that it is poorly absorbed from
the gastrointestinal tract. It is no longer used in hydatid disease.
• 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 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 therapy are: mild abdominal pain,
nausea, vomiting, pruritis, dizziness, alopecia, rash and headache.
Occasionally leucopoenia, eosinophillia, icterus, and mild elevation
in transaminase levels.

PERCUTANEOUS DRAINAGE
OF HYDATID CYST (PAIR)
• PAIR (Puncture, Aspiration, Injection, Re-
aspiration), was proposed in 1986 by the
Tunisian team that first used it in a prospective
study.
• PAIR is a relatively recent and minimally
invasive therapeutic option, that complements or
replaces surgery which was long considered as
the only treatment for CE.
• If a catheter is temporarily left in the cyst after
the procedure for drainage (D), the acronym
PAIRD should be preferred.

PAIR
• This technique, performed using either ultrasound or CT
guidance, involves aspiration of the contents via a special
cannula, followed by injection of a scolicidal agent for at
least 15 minutes, and then reaspiration of the cystic
contents. This is repeated until the return is clear. The cyst
is then filled with isotonic sodium chloride solution.
Perioperative treatment with a benzimidazole is mandatory
• The cysts should be larger than 5 cm in diameter and type
I or II according to the Gharbi ultrasound classification of
liver cysts PAIR can be performed on type III cysts as long
as it is not a honeycomb cyst.

INDICATIONS FOR 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

Contraindications 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.

PAIR
• Benefits Of 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
• Risks 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)

HOW TO PERFORM PAIR
• Basic Requirements:
• Trained personnel
• Equipment, Supplies, Drugs (minimum requirements) :
• 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
• “Fast test” for checking the presence of bilirubin in the cystic fluid
• 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 STEP BY STEP
• PAIR Protocol (Minimum Requirements):
1. Prophylaxis with albendazole
2. Puncture and parasitological examination (if possible) or fast
test for antigen detection in cyst fluid
3. Aspiration of cystic fluid (10-15 cc)
4. Test for bilirubin in cyst fluid
5. If bilirubin present: →→ →→ stop procedure
6. If no bilirubin present: →→ →→ aspirate all cystic fluid
7. Injection of 95 % ethanol solution or hypertonic saline (1/3 of
the amount of aspirated fluid)
8. Re aspiration of protoscolicide solution after 15 minutes
9. New parasitological control if possible

Management of the patient in case
of allergic/anaphylactic reaction
• • Skin reaction (urticaria [hives], oedema) without arterial blood
pressure (ABP) changes (ABP>115-70 mm HG):
• Inject hydrocortisone and/or anti-histamine drug
• Careful monitoring of ABP
• • Moderate decrease in ABP (115-70>ABP>95-50 mm Hg)
• Temporarily stop the procedure
• • Marked decrease in ABP (ABP<9O-50 mm Hg)
• Stop the procedure
• Inject 1/3 mL of epinephrine (1mg/mL) IM or (3mL of a saline
solution of epinephrine-1mL/10mL-through the IV catheter)
• • If ABP<95-50:
• new injection of epinephrine up to 1mL (IM) or 10mL of the saline
solution of epinephrine (IV)

ENDOSCOPIC MANAGEMENT OF
HYDATID CYST
•
• The ERCP is effective in diagnosing biliary tree
involvement from the cyst. 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.

SURGICAL TREATMENT
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; and very small cysts are contraindications.

PRINCIPLES OF HYDATID
SURGERY
• 1) Total removal of all infective components of the
cysts
• 2) The avoidance of spillage of cyst contents at
time of surgery
• 3) Management of communication between cyst
and adjacent structures
• 4) Management of the residual cavity
• 5) Minimize risks of operation
• All the surgical procedures can be divided into
two large groups, conservative group and
radical group

CONSERVATIVE TECHNIQUE(open
cystectomy)
• The conservative technique consists of
aspiration of the cyst, instillation of scolicidal
agents and evacuation of the cyst contents
and leaving the pericyst. The residual
pericyst is managed by marsupialization,
which consists of suturing the edges of
opened pericyst with the skin, capitonnage
(suture obliteration), partial pericystectomy,
omentoplasty and suture closure of the
pericyst cavity after filling it with saline.

RADICAL SURGICAL
PROCEDURES
• Pericystectomy
• Lobectomy
• Hepatectomy .
• Radical procedures have lower rate of
complications and recurrences but many
authors consider them inappropriate,
claiming that intraoperative risks are too
high for a benign disease.

• Pericystectomy – This procedure involves non-
anatomical resection of cyst and surrounding
compressed liver tissue. This is technically more
difficult procedure than cystectomy and can be
associated with considerable blood loss; it can
also be hazardous in the case of large and
complicated cysts when the cyst distorts vital
anatomical structures.
• Hepatic resections – is the only surgical therapy
for E. multilocularis as the disease is infiltrative
and disease margin is ill defined. The arguments
against hepatic resection as a primary modality of
treatment are that outside of dedicated liver units
there is considerable morbidity and mortality from
resection of what is essentially a benign condition
and also distortion of anatomy makes surgery
more difficult.

LAPAROSCOPIC MANAGEMENT
OF HYDATID CYSTS
• A special instrument has been developed for the
removal of the hydatid cyst with the laparoscope
called the perforator-grinder-aspirator
apparatus. The instrument penetrates the cyst,
grinds the particulate matter and sucks it all out.
The advantage of this instrument over that of
conventional suction apparatus is that it does not
gets blocked by the daughter cysts and laminated
membranes. Vacuum obliteration of cavity is
carried out with application of – 250 mbar of
negative pressure, which obliterates the cystic
cavity by clinging to the opposing cyst walls.

COMPLICATIONS OF 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.

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