**2. Pathophysiology**

The agent of hydatid cysts is *Echinococcus granulosus* which belongs to the tapeworm family of cestodes. The tapeworm consists of four segments. The most important segment is the first segment, which consists of four hooked structures that help the pathogen attach to the tissues. The life cycle of the pathogen is unique and explains the pathology.

The hydatid cyst lesion has a round cystic structure and consists of three main layers: an external fibrous pericyst 2–4 mm thick, mainly composed of the host's tissues to protect itself from the cyst; 2-mm-thick middle, nucleus-free hyaline layer, also known as ectocyst, or the laminar membrane in other words; and parasitic inner germinal membrane, known as endocyst. The annual growth rate of the cysts is 1–3 cm per year.

**98**

*Overview on Echinococcosis*

[1] Manterola C, Urrutia S. Morbilidad postoperatoria en pacientes con hidatidosis hepática complicada. Revista Chilena de Infectología.

study. World Journal of Surgery.

[10] Ozaslan E. Therapeutic endoscopic retrograde cholangiopancreatography and related modalities have many roles in hepatobiliary hydatid disease. World Journal of Gastroenterology.

2001;**25**(1):28-39

2006;**12**(30):4930-4931

2014;**20**(41):15253-15261

[12] Akcakaya A, Sahin M,

stenting for selected cases of biliary fistula after hepatic hydatid surgery. Surgical Endoscopy. 2006;**20**(9):1415-1418

[13] Zeybek N, Dede H, Balci D, Coskun AK, Ozerhan IH, Peker S, et al. Biliary fistula after treatment for hydatid disease of the liver: When to intervene. World Journal of Gastroenterology. 2013;**19**(3):355-361

[14] Adas G, Arikan S, Gurbuz E, Karahan S, Eryasar B, Karatepe O, et al. Comparison of endoscopic

2010;**20**(49):223-227

therapeutic modalities for postoperative biliary fistula of liver hydatid cyst: A retrospective multicentric study. Surgical Laparoscopy, Endoscopy & Percutaneous Techniques.

[11] Dolay K, Akbulut S. Role of endoscopic retrograde

cholangiopancreatography in the management of hepatic hydatid disease. World Journal of Gastroenterology.

Karakelleoglu A, Okan I. Endoscopic

[2] Singh V, Reddy DC, Verma GR, Singh G. Endoscopic management of intrabiliary-ruptured hepatic hydatid cyst. Liver International.

[3] Al Karawi MA, Mohamed AE, Yasawy I, Haleem A. Non-surgical endoscopic trans-papillary treatment of ruptured echinococcosis liver cyst obstructing the biliary tree. Endoscopy.

[4] Al Karawi MA, Yazawy MI, El Sheikh FS, Mohamed AR. Endoscopic management of biliary hydatid disease.

Report on six cases. Endoscopy.

Ell C. 25 years of endoscopic

therapy in the management of hepatobiliary hydatid disease. Journal of Clinical Gastroenterology.

[5] Rabenstein T, Schneider HT, Hahn EG,

sphincterotomy in Erlangen: Assessment of the experience in 3.498 patients. Endoscopy. 1998;**30**(2):194-201

[6] Ozaslan E, Bayraktar Y. Endoscopic

[7] Pinto P, López R. Evolución natural de la fístula biliar externa post cirugía del quiste hidatídico hepático. Revista Chilena de Cirugía. 2010;**62**(5):476-479

[8] De Aretxabala X, Pérez OL. The use of endoprótesis in biliary fistula of hydatid cyst. Gastrointestinal Endoscopy. 1999;**49**(6):797-799

[9] Zaouche A, Haouet K, Jovini M, El Hachaichi A, Dziri C. Management of liver hydatid cyst with a large biliocystic fistula: Multicenter retrospective

**References**

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2006;**26**(5):621-624

1987;**19**(2):81-83

1991;**23**(5):278-281

2002;**35**(2):160-174

The germinative layer on the wall of the cyst is the site of asexual proliferation and secretes the cystic fluid. The larvae also emerge from this layer. If the connections between the laminar layer and the pericyst layer break down, the oxygenation of the cyst deteriorates and cannot produce liquid. The inevitable consequence of this is that the growth of the cyst stops.

#### **2.1 Life cycle of** *E. granulosus*

The disease lives in canines that are infected by eating the internal organs of sheep which contain hydatid cysts. The eggs in the cysts adhere to the small intestines of the dogs and become adult tapeworms attached to the intestinal wall. Each worm holds about 500 ovaries in the intestine. Dog feces containing infected eggs contaminate grasses and farmland, and the ovaries are swallowed by intermediate hosts such as sheep, cattle, pigs, and humans. The egg has chitinous envelopes that are dissolved with gastric juice. The released ovary then passes through the intestinal mucosa and is transported by the portal vein to the liver, where it develops in an adult cyst. Most cysts are caught in hepatic sinusoids, and therefore 70% of hydatid cysts occur in the liver, often in the right inferior segments. The placed embryo is immediately transformed into larvae. The larvae turn to the vesicle (scolex) and to the cyst at the end. The larvae can multiply asexually. Thus, there may be more than one living larva in a single cyst. Several pathogens pass through the liver, and the lung keeps them in its capillary bed, or they enter to the systemic circulation to form cysts in the lungs, spleen, brain, or bones.

### **3. Diagnosis**

Uncomplicated cysts may be silent and incidental. Rarely, the affected patient has symptoms such as right upper quadrant pain or abdominal distension. The cysts may be secondary infected (usually by *E. coli*), invade other organs, or even cause ruptures leading to an allergic or anaphylactic reaction.

There are four medical tests used in diagnosis: Casoni skin test, the complement fixation test, *Echinococcus* IHA (indirect hemagglutination) test, and enzymelinked immunosorbent assay (ELISA). The Casoni skin test is no longer used. The complement fixation test (Weinberg) is not widely used in diagnosis (the sensitivity is about 80%), but it is useful in follow-up because it becomes negative after the first year of the treatment. Its sensitivity is about 90% by then.

The *Echinococcus* IHA (indirect hemagglutination) is the most commonly used diagnostic test in practice. Its sensitivity is 90%. The *Echinococcus* IHA test is done by the patient's serum taken and diluted on microplates in times of 2, 4, 8, 16, 32, 64, 128, 256 … 2048. A kit recognizing echinococcal antibodies is added to each microplate medium. If erythrocytes form agglutination in the presence of a kit, this indicates that the test is positive at that density. It is significant that IHA is positive at dilutions exceeding 1/128. However, many authors accept a 1/256 dilution as the presence of the disease. Positivity at lower dilutions means that the patient got cured or the disease is currently inactive.

It should be kept in mind that once IHA is positive, it may remain positive for more than 20 years. In a comprehensive epidemiological study published in Turkey, the positive prevalence of the *Echinococcus* IHA is 291/100,000 in the general population.

The diagnosis of hydatid cyst disease is based on the findings of ELISA for echinococcal antigens, and results are positive in approximately 85% of infected

**101**

*The Surgical Management of Hydatid Cyst of the Liver: What is New?*

patients. The test may be negative if it is not leaking or the parasite is no

In conclusion, the serological screening tests based on antigens (e.g., indirect hemagglutination, latex agglutination, ELISA) are highly associated with falsepositive and false-negative results. However, while ELISA detection of specific antigens and immune complexes of the cyst has a much higher sensitivity, ELISA and radioallergosorbent test (RAST) can also detect specific IgE antibodies. Antigen 5 (arc-5) and antigen B8 are the major parasitic antigens having diagnos-

Eosinophilia occurs in approximately 30% of infected patients. Ultrasonography

Calcification of female cysts occurs in approximately 75% of cases and 50% of the surrounding cyst wall [1]. As healing occurs, the entire cyst densely calcifies, and a lesion with this appearance is usually dead or ineffective. Daughter cysts usually occur at a peripheral location within the mother cyst and are typically more hypodense than the mother cyst. Abdominal MRI may be useful in assessing pericyst, cyst matrix, and daughter cyst characteristics. MRI is the technique that best shows pericyst or "cyst hydatid sand" (free floating membranes) and daughter cysts. Fibrous and rigid pericysts appear as a hypodense ring on both T1- and T2-weighted images. The hydatid matrix is hyperdense in T2-weighted images and hypodense in T1-weighted images. Daughter cysts may be seen in both T1-

The treatment and the follow-up procedures are based on the cyst and the symptoms of the patients. Below, you may find the clinical and radiological staging

Stage 3: Symptomatic + presence of liver dysfunction (e.g., AST, ALT

Type 2: The decomposition of the germinative membrane and the pericyst.

and CT scan of the abdomen are very sensitive in hydatid cyst detection, and the appearance of cysts on images depends on the stage of cyst development. Ultrasound images may show peripheral calcifications of cysts or curved bands of delaminated endocysts, called lotus. In CT scans, hydatid cysts are usually seen as

*DOI: http://dx.doi.org/10.5772/intechopen.90726*

longer alive.

tic value.

hypodense lesions.

and T2-weighted images.

**3.1 Clinical staging**

elevation).

• CL

Stage 1: Asymptomatic.

**3.2 Gharbi classification in USG**

Type 1: Pure liquid collection.

Type 3: Multivesicular type.

Type 5: The calcified wall.

**3.3 2001 WHO classification**

Type 4: Heterogeneous echo pattern.

○ Unilocular anechoic cystic lesion [2]

○ No any internal echoes or septations

as well as WHO classification for hydatid cysts.

Stage 2: Symptomatic (right upper quadrant pain).

#### *The Surgical Management of Hydatid Cyst of the Liver: What is New? DOI: http://dx.doi.org/10.5772/intechopen.90726*

patients. The test may be negative if it is not leaking or the parasite is no longer alive.

In conclusion, the serological screening tests based on antigens (e.g., indirect hemagglutination, latex agglutination, ELISA) are highly associated with falsepositive and false-negative results. However, while ELISA detection of specific antigens and immune complexes of the cyst has a much higher sensitivity, ELISA and radioallergosorbent test (RAST) can also detect specific IgE antibodies. Antigen 5 (arc-5) and antigen B8 are the major parasitic antigens having diagnostic value.

Eosinophilia occurs in approximately 30% of infected patients. Ultrasonography and CT scan of the abdomen are very sensitive in hydatid cyst detection, and the appearance of cysts on images depends on the stage of cyst development. Ultrasound images may show peripheral calcifications of cysts or curved bands of delaminated endocysts, called lotus. In CT scans, hydatid cysts are usually seen as hypodense lesions.

Calcification of female cysts occurs in approximately 75% of cases and 50% of the surrounding cyst wall [1]. As healing occurs, the entire cyst densely calcifies, and a lesion with this appearance is usually dead or ineffective. Daughter cysts usually occur at a peripheral location within the mother cyst and are typically more hypodense than the mother cyst. Abdominal MRI may be useful in assessing pericyst, cyst matrix, and daughter cyst characteristics. MRI is the technique that best shows pericyst or "cyst hydatid sand" (free floating membranes) and daughter cysts. Fibrous and rigid pericysts appear as a hypodense ring on both T1- and T2-weighted images. The hydatid matrix is hyperdense in T2-weighted images and hypodense in T1-weighted images. Daughter cysts may be seen in both T1 and T2-weighted images.

The treatment and the follow-up procedures are based on the cyst and the symptoms of the patients. Below, you may find the clinical and radiological staging as well as WHO classification for hydatid cysts.

### **3.1 Clinical staging**

*Overview on Echinococcosis*

this is that the growth of the cyst stops.

cysts in the lungs, spleen, brain, or bones.

cured or the disease is currently inactive.

ruptures leading to an allergic or anaphylactic reaction.

first year of the treatment. Its sensitivity is about 90% by then.

**3. Diagnosis**

**2.1 Life cycle of** *E. granulosus*

The germinative layer on the wall of the cyst is the site of asexual proliferation and secretes the cystic fluid. The larvae also emerge from this layer. If the connections between the laminar layer and the pericyst layer break down, the oxygenation of the cyst deteriorates and cannot produce liquid. The inevitable consequence of

The disease lives in canines that are infected by eating the internal organs of sheep which contain hydatid cysts. The eggs in the cysts adhere to the small intestines of the dogs and become adult tapeworms attached to the intestinal wall. Each worm holds about 500 ovaries in the intestine. Dog feces containing infected eggs contaminate grasses and farmland, and the ovaries are swallowed by intermediate hosts such as sheep, cattle, pigs, and humans. The egg has chitinous envelopes that are dissolved with gastric juice. The released ovary then passes through the intestinal mucosa and is transported by the portal vein to the liver, where it develops in an adult cyst. Most cysts are caught in hepatic sinusoids, and therefore 70% of hydatid cysts occur in the liver, often in the right inferior segments. The placed embryo is immediately transformed into larvae. The larvae turn to the vesicle (scolex) and to the cyst at the end. The larvae can multiply asexually. Thus, there may be more than one living larva in a single cyst. Several pathogens pass through the liver, and the lung keeps them in its capillary bed, or they enter to the systemic circulation to form

Uncomplicated cysts may be silent and incidental. Rarely, the affected patient has symptoms such as right upper quadrant pain or abdominal distension. The cysts may be secondary infected (usually by *E. coli*), invade other organs, or even cause

There are four medical tests used in diagnosis: Casoni skin test, the complement

The *Echinococcus* IHA (indirect hemagglutination) is the most commonly used diagnostic test in practice. Its sensitivity is 90%. The *Echinococcus* IHA test is done by the patient's serum taken and diluted on microplates in times of 2, 4, 8, 16, 32, 64, 128, 256 … 2048. A kit recognizing echinococcal antibodies is added to each microplate medium. If erythrocytes form agglutination in the presence of a kit, this indicates that the test is positive at that density. It is significant that IHA is positive at dilutions exceeding 1/128. However, many authors accept a 1/256 dilution as the presence of the disease. Positivity at lower dilutions means that the patient got

It should be kept in mind that once IHA is positive, it may remain positive for more than 20 years. In a comprehensive epidemiological study published in Turkey, the positive prevalence of the *Echinococcus* IHA is 291/100,000 in the general

The diagnosis of hydatid cyst disease is based on the findings of ELISA for echinococcal antigens, and results are positive in approximately 85% of infected

fixation test, *Echinococcus* IHA (indirect hemagglutination) test, and enzymelinked immunosorbent assay (ELISA). The Casoni skin test is no longer used. The complement fixation test (Weinberg) is not widely used in diagnosis (the sensitivity is about 80%), but it is useful in follow-up because it becomes negative after the

**100**

population.

Stage 1: Asymptomatic.

Stage 2: Symptomatic (right upper quadrant pain).

Stage 3: Symptomatic + presence of liver dysfunction (e.g., AST, ALT elevation).
