Hydatid Cyst Of Liver

Treatment of the hydatid cysts:

Ans. is ‘b’ i.e., Echinococcus granulosus

Ans. is ‘a’ Caused by E. granulosus; ‘b’ In 80% of cases, cyst is single

Hydatid cyst of liver (or Echinococcosis)

• Cystic hydatid disease is caused by the larval/cyst stage of the tapeworm – Echinococcus granulosus (Other Echinococcus species affecting human are E. multiloculasis, E. vogeli & E. oligarthus).

– Man is the intermediate host of Echinococcus.

– Dog is the definitive host.

– Sheeps are the usual intermediate host, but humans are accidental intermediate hosts.

• Organs commonly involved are liver and lung.

– The liver is involved in about two-third of E. granulosus infection and in nearly all E. multiloculasis infection.

• Usually the cysts are single and involve the rt. lobe of liver.
• Clinical manifestation:
• Slowly enlarging echinococcal cysts are usually asymptomatic until their expanding size or their space occupying effect in the involved organ prduces symptoms.
• Symptoms when produced are – abdominal pain, dyspepsia, vomiting, hepatomegaly.
• Diagnosis
• U/S and CT can diagnose the cystic lesion. There are certain signs which if present are pathognomic of hydatid ds.

– daughter cyst within the large cyst (may produce rosette appearance)

– calcification of the wall

• Serodiagnostic assay (ELISA) can be helpful in over 85% of patients.
• Treatment

Books differ on the treatment.

According to Harrison

• Surgery has traditionally been the principal definitive method of treatment.
• Currently ‘PAIR’ is the preferred method of t/t for sonologically appropriate lesions.

– PAIR is contraindicated for

–   superficially located cysts (because of the risk of rupture)

– for cysts with multiple thick internal septal divisions (honeycombing pattern)

for cysts communicating with the biliary tree.

– dead or inactive cysts

– PAIR stands for percutaneous aspiration, infusion of scolicidal agents and reaspiration.

–           In PAIR pt. is given prophhylactic coverage of albendazole; cyst is aspirated under ultrasound or CT guidance and scolicidal agents (ethanol or hypertonic saline) infused. Scolicidal agent is then reaspirated.

–           PAIR has been found to be equally effective as surgery with less morbidity and shorter hospital stay.

• Surgery remains the treatment of choice for cysts where PAIR is not possible or cysts are refractory to PAIR and for complicated cysts (e.g. those communicating with the biliary tract).

Pericystectomy is the preferred surgical approach, in which the complete cyst with surrounding fibrous tissue are removed.

If surgical cystectomy is not technically feasible, then formal liver resection can be done.

• For those patients who are poor candidates for cyst directed intervention (i.e. PAIR or surgery) – long durations of Albendazole is the mainstay of therapy.

According to Schwartz (and Sabiston)

– Surgery is the preferred method of treatment, unless the cysts are small or the patient is not a suitable candidate for surgical resection.

– For most cysts surgical resection involving laparoscopic or open complete cyst removal with instillation of a scolicidal agent is preferred and usually is curative.

– If complete cystectomy is not possible, then formal anatomic liver resection can be used.

• Treatment of Echinococcus multilocularis.

–  E. multilocularis cyst is always multiloculated

– T/t is surgical resection

Ans is ‘d’ i.e. Hepatic resection is never done 

Laparoscopic aspiration, unroofing and evacuation of the hepatic hydatid cysts can be done.

Ans. is ‘a’  i.e. lung cyst 

• The PAIR technique can be performed on liver, bone, and kidney cysts but should not be performed on lung and brain cysts. 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.
• Contraindications:

1. Early pregnancy
2. Cysts in lung, spine, brain & heart.
3. Inaccessible cysts or cysts in risky location
4. superficially located cysts (risk of spillage)
5. Inactive or calcified lesions (type IV & type V according to Gharbi classification)
6. Cysts communicating with the biliary tree (risk of sclerosing cholangitis from the scolecoidal agent)
7. Cysts communicating with abdominal cavity, bronchi or urinary tract

Ans. is ‘c’ i.e. 20% saline is scolicidal 

• Most common site is liver followed by lung. Other sites which may be involved by E. granulosus are abdominal cavity

– kidney

– brain

– hone

• Scolicidal agents used in hydatid surgery

20% hypertonic saline

–       0.5% silver nitrate

95% sterile ethanol

Absolute alcohol

– Mebendazole 2.4 ,ug/m1

There is no place for the use of formaldehyde as a scolicidal agent.

Answer is ‘d’ Serum examination 

• Serological tests are the most sensitive and specific tests; includes Immunoblast test, arcs test, ELISA and indirect hemagglutination tests.
• “The immunoblast test, where available, is the test of choice.” – CMDT, 2005, p 1463.
• Casoni’s test – Intradermal injection of 0.2 ml of fresh sterile hydatid fluid produces a wheal of 5 cm in diameter within half an hour in pts with hydatid disease. It has been abandoned because of poor specificity.

Ans. is ‘c’ i.e., Cirrhosis 

Ans. is ‘d’ i.e., Povidone Iodine 

Ans. is ‘d’ is more common in lower lobe

After going through so many books I could get hold of the following points regarding hydatid cyst of lung.

• Lung in the II^nd MC site for hydated cyst (Liver is the Ist)*
• Only 10% of pulmonary cyst are associated with hepatic cyst.
• About 20% of pulmonary cysts are bilateral.
• Usually seen in the lower lobes of lung.
• Calcification in rare (Note that the calcification is very common in hydatid cyst of liver).
• It may rupture into the bronchial tree or the peritoneal cavity.

Ans. C: Most commonly involves lung

Theoretically, echinococcosis can involve any organ.

The liver is the most common organ involved, followed by the lungs. These 2 organs account for 90% of cases of echinococcosis.

Two benzimidazoles are used, albendazole and mebendazole. Albendazole is administered in several 1-month oral doses separated by 14-day intervals.

In AE (alveolar echinococcosis), radical surgical excision is coupled with chemotherapy in operable cases and long-term aggressive chemotherapy for partially resected or unresectable lesions.

In CE (cystic echinococcosis), consider risks and benefits, indications, and contraindications for each case before making a decision regarding the type and timing of surgery.

Role of PAIR in CE: 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 respirations 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 (4 days prior to the procedure and 1-3 months after).

Ans. B: Man

Man is intermediate host for hydatid disease and malaria.

Man is definitive host for majority of human parasitic infections like filarial, roundworm or hookworm.

Ans. B: Liver

The majority of hydatid cysts occur in the liver

Echinococcosis/Hydatid disease/Echinococcal disease

• There are three different forms of echinococcosis found in humans, each of which is caused by the larval stages of different species of the tapeworm of genus Echinococcus.
• The first of the three and also the most common form found in humans is cystic echinococcosis (also known as unilocular echinococcosis), which is caused by Echinococcus granulosus.
• The second is alveolar echinococcosis (also known as alveolar colloid of the liver, alveolar hydatid disease, alveolococcosis, multilocular echinococcosis, “small fox tapeworm”), which is caused by Echinococcus multilocularis and
• The third is polycystic echinococcosis (also known as human polycystic hydatid disease, neotropical echinococcosis), which is caused by Echinococcus vogeli and very rarely, Echinococcus oligarthus.
• Alveolar and polycystic echinococcosis are rarely diagnosed in humans and are not as widespread as cystic echinococcosis

Definitive Hosts

• E. granulosus: dogs and other canidae
• E. multilocularis: foxes, dogs, other canidae and cats
• E. vogeli: bush dogs and dogs
• E. oligarthus: wild felids

Intermediate Hosts

• E. granulosus: sheep (optimum intermediate host), goats, swine and other wild herbivores (Man is an accidental host and leads to dead end of life cycle)
• E. multilocularis: small rodents
• E. vogeli: rodents
• E. oligarthus: small rodents

Liver cyst

• Majority of hydatid cyst occur in the liver, causing symptoms that may include chronic abdominal discomfort, occasionally with a palpable or visible abdominal mass.
• Liver cyst tend to occur more on the right side

Ans. D: USG

Laboratory Studies

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%. Almost every serodiagnostic technique has been evaluated for echinococcosis, with variable results.

– The 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 Studies

– Plain films

Findings from plain films of the chest, abdomen, or any other involved site are, at best, nonspecific and mostly nonrevealing. A thin rim of calcification delineating a cyst is suggestive of an echinococcal cyst.

– Ultrasound

Ultrasonography helps in the diagnosis of hydatid cysts when the daughter cysts and hydatid sand are demonstrated.

The accuracy of ultrasound evaluations remains operator-dependent.

CT scan

CT scan has an accuracy of 98% and the sensitivity to demonstrate the daughter cysts.

It is the best test for the differentiation of hydatid from amebic and pyogenic cysts in the liver.

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

Other Tests

–  Casoni test

Historically, an intradermal skin test (Casoni test) was used and had a sensitivity of 70%.

It is now largely abandoned because of its low sensitivity, low accuracy, and potential for severe local allergic reaction.

Ans. Will not calcify

Ans. is ‘b’ i.e., Calcification is common in lung

Hydatid disease

• Liver cysts
• The majority of hydatid cysts occur in the liver, causing symptoms :
• Chronic abdominal discomfort
• Palpable abdominal mass
• Allergic reactions due to cyst rupture – skin rash, anaphylactic shock, or death.
• Abscess formation due to secondry bacterial infection
• Liver cysts occur more frequently in the right lobe.

Lung cyst

• Second most common organ (after liver)
• Usually asymptomatic
• Occasionally may cause symptoms.
• Least common site of calcified hydatid cyst.

Radiographic signs

1. Meniscus sign
2. Water – lily sign, camalote sign
3. Rising sun sign, serpent sign
4. Empty cyst sign

Hydatid Cysts most in common in Liver.  In humans hydatid disease is caused by the larvae of a tapeworm called Echinococcus granulosus.

The disease is spread when food or water that contains the eggs of the parasite is eaten or by close contact with an infected animal.

Alveolar disease usually begins in the liver but can spread to other parts of the body, such as the lungs or brain.

When the liver is affected the person may have abdominal pain, weight loss, and turn slightly yellow from jaundice.

Ans. b. E. multilocularis

Ans. is ‘b’ i.e., CT-scan

• For hydatid cyst

• 1st line investigation – Ultrasound

• Investigation of choice – CT-scan