HYDATID CYST OF THE LIVER

HYDATID CYST OF LIVER

1. HYDATID CYST OF THE LIVER

2. The disease is caused by Echinococcus granulosus , transmitted by dogs which are the chief mediators (host) and man is the intermediate host . After swallowing the ova, they penetrate gastric mucosa, reach retroperitoneal structures, penetrate portal vein directly and then enter into liver. Having reached liver, the organisms grow and develop their own protective layer and form hydatid cyst.

3. Layers of hydatid cyst 1 . The adventitia ( pseudocyst ) : This is the fibrous layer derived from the liver tissue. It is the reaction of liver to the parasite . It is adherent to the liver and cannot be separated pericyst .

4. 2. The ectocyst (laminated membrane): It is white anc elastic and is produced by endocyst . It is this layer which gets peeled off at surgery.

5. 3. The endocyst : This is called germinal epithelium and it is the innermost part of hydatid cyst. It secretes hydatid fluid inside and ectocyst outside. Within the hydatid fluid, the 'brood capsules' develop within which the scolices of Echinococcus granulosus develop.

6. LAYERS OF HYDATID CYST

7. Clinical features It can be silent-without any symptoms throughout life, accidentally discovered on routine examination. Dragging pain in the upper abdomen due to hepatomegaly . Liver is enlarged, has a smooth surface, round borders and is nontender .

8. Typical hydatid thrill can be present on rare occasions. Hydatid thrill is demonstrated by 3-finger method. Keep 3 fingers over the liver, percuss over the middle finger and get the impulse by other 2 fingers (fluid thrill). Patient may present as an emergency with severe abdominal pain following minor trauma. May present as an emergency with features of anaphylatic shock without any obvious cause.

9. Investigations 1 . USG can detect the cyst, localise the cyst and is used for aspiration purposes. Group-I : Active group-cyst larger than 2 cm and often fertile Group-2: Transition group-cyst starting to degenerate because of host resistance or treatment; may contain viable protoscolices Grou p-3: Inactive group-degenerated partially or totally calcified cyst; unlikely to contain viabl protoscolices

10. 2. Plain X-ray abdomen may demonstrate speckled calcification. 3. CT scan may be necessary in selected cases The cyst which is superficial and has reached surface , should be operated upon . 4 . ERCP if there is obstructive jaundice-in such cases, a wide sphincterotomy should be given so as to allow free drainage of the hydatid contents into the duodenum.

11. 5. Casoni's intradermal test: Sensitivity and specificity of this test is low and hence, no longer used. 6. ELISA and immunoelectrophoresis may point towards the diagnosis. PAIR TEST : Puncture , Aspiration, Injection and Reaspiration .

12. Treatment I . Conservative 1. Calcified cysts are dead cysts. They are left alone. 2. Symptomless, small hydatid cyst can be left alone. Once symptomatic , or if the size is more than 5 cm, they may be treated. II. Medical treatment Albendazole 8 mg/kg or 400 mg BD is given for 21 days followed by drug holiday for 2 weeks.

13. If no improvement occurs maximum of 3 such cycles can be given. Watch for neutropenia

14. III. Surgery There are different types of surgeries for hydatid disease of the liver which have been summarised below.

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