hydatid cyst, pathophysiology, rupture of cyst, complications, investigation, treatment surgical and medical, garbi and who classification

1. HYDATID CYST
Dr Rojan Adhikari
FCPS Resident
General Surgery
Kathmandu Model Hospital

2. Hydatid cyst
• Echinococcosis (hydatid disease) is a
zoonosis caused by the larval stage of
Echinococcus.
• Species: granulosus , multilocularis,
ligartus, vogeli
• cestodes (flat worms)

3. Epidemology
• The first case was observed in North America
in 1808 and published in 1822.
• E. granulosus is commonly seen in the
Mediterranean, South America, the Middle
East, Australia, and New Zealand, and is the
most common type of hydatid disease in
humans
• In humans, 50–75% of the cysts occur in the
liver, 25% are located in the lungs, and 5–10%
distribute along the arterial system

4. Life cycle
• Definitve host- Dog and some other carnivore
• intermediate host – most commonly sheep,
• Humans are the accidental intermediate host
• The adult worm of the parasite lives in the
proximal small bowel of the definitive host
attached by hooklets to the mucosa

6. Life Cycle
After ingesion by intermittent host ovum
loses the protective chitinous layer and is
digested in the duodenum.
The released hexacanth embryo (oncosphere)
passes through the intestinal wall into the
portal circulation and develops into cysts
within the liver.
The definitive host eats the viscera of the
intermediate host and the cycle is completed.

7. Pathology
• By 21 days becomes visible with with naked eye
• Host tissue response- covers parasite in fibous tissue
• Parasite responds by forming inert chitinous material

8. • There are three known forms of echinococcosis in
humans:
(i) cystic echinococcosis (hydatid disease)
caused by Echinococcus granulosus,
(ii) alveolar echinococcosis (alveolar hydatid disease)
caused by Echinococcus multilocularis, and
(iii) polycystic echinococcosis caused by Echinococcus
vogeli

9. • Hydatid cyst
– Unilocular
– Increases size about 1 to 1.5mm/month
– Fluid is under pressure
– Liters of fluid

10. Pericyst
• thin, indistinct fibrous tissue layer representing
an adventitial reaction to the parasitic infection.
• acts as a mechanical support for the hydatid cyst
• metabolic interface between the host and the
parasite.
• As the cyst grows, bile ducts and blood vessels
stretch and become incorporated within this
structure, which explains the biliary and
hemorrhagic complications of cyst growth and
difficulties with resection.
• Over time, the pericyst calcifies.

11. The fully developed wall of the cyst
• Endocyst (germinative )
• microscopic dimensions
• responsible for the
production of the
– crystal-clear hydatid
fluid
– ectocyst
– brood capsules
– scoleces
– the daughter cysts
Ectocyst (laminated membrane)
• is a cuticular chitinous
structure without nuclei
• never grows thicker than 5
mm, regardless of cyst size.

12. Cyst layers and contents

13. • Hydatid fluid is antigenic
• This antigenicity is rarely of great clinical
significance
• Allergic reactions range from skin rash to a frank
anaphylactic reaction
• The antigenicity of hydatid fluid is the basis of
serodiagnostics

14. Clinical presentation
• The clinical features of hydatid liver disease
depend on the site, size, stage of
development, whether the cyst is alive or
dead, and whether the cyst is infected or not.
• Pain in the RUQ or epigastrium is the most
common symptom, whereas hepatomegaly
and a palpable mass are the most common
signs.

15. Clinical Presentation
SYMPTOMS Percentage
Asymptomatic 75%
Abdominal pain 20%
Dyspepsia 13 %
Fever and chills 8 %
Jaundice 6%

16. Clinical Presentation
SIGNS
• Right upper quadrant mass
•Right upper quadrant tenderness

17. Suppuration and Secondary Bacterial Infection
• most frequent cause of infection is a cystobiliary
communication
• Clinically presents at pyogenic liver abscess
• An infected hydatid cyst undergoes structural changes
and the parasite dies

18. Pressure Effects
• grow in the direction of the least resistance
• Pressure effects appear sooner or later
• symptoms result from direct pressure or distortion
of neighboring structures or viscera.
• An enlarging cyst
– atrophy of surrounding hepatocytes
– fibrosis
– compensatory hypertrophy of the remaining liver
parenchyma
– replaces an entire liver lobe

19. • Serious consequence of cyst enlargement is cyst
Rupture
• Three types of cyst rupture have been addressed:
– obscure
– free
– communicant rupture

20. Obscure (Internal) Rupture
Injury or penetration of bile between pericyst and ectocyst
Ruptue of ectocyst
Protoscolesces occupies spaces
Develops 100s of daughter cyst
Unilocular  multilocular
Within yellow fluid of gelatin like amorphous mass inside
pericyst

21. Free Rupture
In free rupture, the hydatid contents disseminates throughout the
peritoneal or pleural cavity

22. Intraperitoneal Rupture
• Hydatid cyst grows in the direction of the least resistance
• superficial portion of the pericyst is stretched, thinned out
• cyst irregularly shaped, fibrous whitish structure
protruding from normal liver parenchyma
• Cysts reaching the anterior and inferior part of the liver
continue to grow, protruding into the abdominalcavity
•high intracystic pressure causes rupture
of both univesicular and multivesicular
cysts

23. Clinical presentations of
intraperitoneal rupture
(i) In acute symptomatic rupture,
– peritoneal irritation and acute abdominal symptoms occur
– The incidence is about 1% to 4%.
(ii) In anaphylactic shock
– rupture precipitates severe circulatory collapse, which
may be fatal mask the abdominal manifestations
(iii) In silent rupture, the patient presents with disseminated
abdominal hydatidosis, unaware when the rupture occurred

24. • Intraperitoneal rupture is a life-threatening complication that
results in secondary echinococcosis
• •Multiple cysts develop throughout the peritoneal cavity
causing
– intestinal obstruction,
– gross abdominal distention,
– ascites,
– and cachexia after years of the rupture.
• This is the secondary, smaller life cycle for the parasite,
occurring only in the intermediate host.

25. Intrathoracic Rupture
• Elevated hemidiaphragm and a sterile pleural effusion
can be the first signs of liver hydatid disease
• Upward extension of a subdiaphragmatic cyst is usually
asymptomatic, although it can cause dry cough,
dyspnea, chest pain, and toxemia
• The pleura and adherent basal lung segments often
become inflamed and indurated
• Frank intrapleural rupture with empyema
(hydatopiothorax) is rare
• pneumonitis or lung abscess

26. • The hydatid cyst may erode into a bronchiole and the contents
can be evacuated
• Rupture into bronchiole daughter cysts in the sputum
• Ocassionally a bronchobiliary fistula will arise
Expectoration of bile-tinged sputum
• The incidence of diaphragmatic or transdiaphragmatic
thoracic involvement by hydatid cysts in the dome of the liver
is rare

27. Communicant Rupture
Hydatid cysts can rupture into physiologic
channels (e.g., biliary, blood vessels) or
adjacent organs (e.g., digestive tract)

28. • In silent rupture, bile leaks from eroded small ducts into the
cyst, causing
– endogenic vesiculation
– suppuration
– eventually death of the parasite
• Such cysts are filled with bile-stained fluid, although no
visible bile duct communications can be seen.
• Probably 80% to 90% of hydatid cyst bile duct ruptures are of
the silent type.

29. • A triad of symptoms characterizes rupture into the bile
ducts:
I. biliary colic
II. partial intermittent or complete ductal obstruction
with cholangitis and jaundice
III. germinative membranes in the feces.

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

31. Lab
• Eosinophilia - 35%
• Bilirubin >2 mg/Dl - 20%
• WBC count <10,000/mm
3
- 10%

32. Investigation
X-ray
• Limited value
• In endemic areas, elevation of the right hemidiaphragm in an
otherwise healthy, asymptomatic patient is highly indicative of
liver hydatidosis
• Sometimes streaklike or round calcification of a senile hydatid
cyst.

33. Ultrasound Imaging
• comparatively cheap, noninvasive, enables
interventional procedures

34. • Pathognomonic USG diagnostic features are
I. unmistakable daughter cysts (rosettes) within the main cyst
cavity
II. detachment of the membrane of the cyst (double-contoured
membrane)
III. agglomeration of daughter cysts in the dependent portion of a
hydatid cyst
IV. calcification of the cyst wall

35. • Based on USG signs, Hassen Gharbi in 1981 classified
liver hydatid cysts into five types
I. pure fluid collection
II. fluid collection with a split wall
III. fluid collection with septa
IV. heterogeneous appearance, and
V. reflecting thick walls

38. CT
• CT gives similar information to ultrasound,
more specific information about the location
and depth of the cyst within the liver.
• Daughter cysts and exogenous cysts are also
clearly visualized, and the volume of the cyst
can be estimated.
• CT is imperative for operative management,
especially when a laparoscopic approach is
utilized.

41. MRI & ERCP
• MRI provides structural details of the hydatid
cyst, but adds little more than ultrasound or
CT, and is more expensive.
• Endoscopic retrograde cholangio
pancreatography (ERCP) may show
communication between the cysts and bile
ducts and can be used to drain the biliary tree
before surgery.

42. Treatment
• Medical, surgical, and percutaneous approaches
may be part of the treatment.
Small cysts (<4 cm) locateddeep in the
parenchymaof the liver,if uncomplicated, canbe
managed conservatively.

43. • Basic principles of treatment are
(1)eradication of the parasite within the cyst,
(2)protection of the host against spillage of
scoleces, and
(3)management of complications

44. Anti helmenthics
• Medical therapy for echinococcosis is limited to the
benzimidazoles (mebendazole and albendazole)
• used alone is only 30% successful.
• Albendazole is readily absorbed from the intestine and
metabolized by the liver to an active form.
Mebendazole is poorly absorbed and is inactivated by
the liver.
• 28-day course may be repeated, after 14 days without
treatment to a total of 3 treatment cycles

45. PAIR technique (percutaneous
aspiration, injection and re-aspiration)
The most frequently utilized protoscolecidal agents
1. 15–20% saline,
2. 95% ethanol,
3. Mebendazole
4. 3% H2O2
5. Betadine
6. Silver nitrate
7. Formalin
Combination is used
Contraindicated in pregnancy, cyst communicating to
billary tree and calcified cyst

46. PAIR technique
Complication of PAIR
• Spillage and anaphylaxis,
• Recurrence
• Mechanical damage to other tissue
• Bilary fistula
• Hemorrhage
• Infection

48. Surgery
• Surgery is still the treatment of choice for
uncomplicated hydatid disease of the liver.
• The objectives of surgical treatment are to:
(1) inactivate the scoleces,
(2) prevent spillage of cyst contents,
(3) eliminate all viable elements of the cyst, and
(4) manage the residual cavity of the cyst.

49. Surgery
Indication
• Large liver cysts with multiple daughter cysts
• Superficially located single liver cysts that may
rupture
• Liver cyst with biliary tree communication or
pressure effects on vital organs or structures
• Infected cysts
• Cysts in lungs, brain, kidneys, eyes, bones

50. Surgical Procedure
• Early on, surgical management of hydatid cysts
via cyst evacuation resulted in a high rate of
peritoneal implantation.
• This problem prompted the use of scolecidal
agents for injection into the cyst and for use in
the surrounding peritoneum.
• The cyst is usually then aspirated through
close suction

51. Surgical Procedures
• The cyst is then unroofed which then can be
followed by
Conservative
• Marsupialisation
• Capittonage
• Partial Pericystectomy
This can be followed by omentoplasty

52. Surgical Procedure
• Radical Pericystectomy: cyst and surrounding
compressed liver tissue
• Hepatic Resection: lobectomy or partial
hepatectomy with entire cyst
• Laparoscopic approach

53. 57 articles were selected for final analysis: one meta-analysis, 9
randomized clinical trials, 5 non-randomized comparative prospective
studies, 7 non-comparative prospective studies, and 34 retrospective
studies

54. Conclusion
• Antihelminthic treatment alone is not the ideal treatment
for liver hydatid cysts.
• More studies in the literature support the effectiveness of
radical treatment compared with conservative treatment.
• Conservative surgery with omentoplasty is effective in
preventing postoperative complications.
• A laparoscopic approach is safe in some situations.
• Percutaneous drainage with albendazole therapy is a safe
and effective alternative treatment for hydatid cysts of the
liver.
• Radical surgery with pre- and post-operative administration
of albendazole is the best treatment option for liver hydatid
cysts due to low recurrence and complication rates.

59. References
• Mastery of surgery
• Sabiston text book of surgery
• UpTodate online
• Centre of Disease Control and Prevention
• Parasitology “K D Chatterjee”

60. Thank you
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