Hydatid Cyst Of Liver
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Hydatid Cyst Of Liver

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Hydatid Cyst Of Liver Hydatid Cyst Of Liver Document Transcript

  • HYDATID CYST OF LIVER Dr.Anil Haripriya
  • 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. Liver hydatidosis is characterized by progressive growth of the hydatid cyst, which in its mature form is a fluid filled cavity, delimited by an external dense host fibrous reaction (pericyst) and two internal parasite derived layers (endocyst). The hydatid cyst grows slowly and remains asysmptomatic for many years. Symptoms arise only when the cyst has grown large enough to cause the pressure on adjacent organs or when a complications occurs. Infection and intrabiliary rupture are the most common complications. Etiopathogenesis Causative Agent Intermediate host Final host Echinococcus granulosus Sheep, Human dog
  • (hydatinosus, cysticus) Echinococcus vogeli Paca dog, fox (Brazil) Echinococcus multilocurlaris Rodents dog,fox, (alveolaris) Echinococcus oligarthrus ? Human dog, fox In E. multilocularis infestation the germinal layer of the cyst sends out processes Into the surrounding host tissue which in turn form fluid filled pockets containg proto-Scolices.The germinal layer continues to spread and multiply like a cancer,therefore It carries mortality upto 50%. E.vogeli infestation is very rare and found occasionally in Brazil.Paca a wild Rodent is the intermediate host and final host is the hunting or domestic dog. Epidemiology It is world wide in distribution and is endemic in many countries like Mediterranean area, the Middle East and South America. In India it is found in the northern states. 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 (psuedocyst / 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 Patients with simple or uncomplicated multivesicular or univesicular cysts are asymptomatic. When symptoms occurs they are caused by pressure on the adjacent organs. Abdominal pain and tenderness are the most common complaints followed by palpable mass. Jaundice and ascites are uncommon. With secondary infection tender hepatomegaly, chills, and spiking temperatures occurs. Urticaria and erythema occur in cases of generalized anaphylactic reaction. With biliary rupture the classic triad of jaundice, biliary colic and urticaria occurs. COMPLICATIONS OF HYDATID CYST Intrabiliary rupture of Hydatid cyst When ruptured in to biliary tree, hydatid cysts commonly manifest with findings of biliary obstruction and cholangitis. The presence of dilated common bile duct, jaundice, or both in addition to a cystic lesion of liver is strongly suggestive of a hydatid cyst with intrabiliary rupture. This
  • complication can be most specifically diagnosed by ERCP or PTC. ( because of risk of intraperitoneal rupture of the hydatid cyst which may result in peritoneal dissemination and anaphylactic reactions because of the spillage of the highly antigenic cyst fluid PTC is contraindicated in hydatid disease of liver). The presence of intrabiliary rupture requires exploration and drainage of the biliary tract. During the exploration the biliary tree is cleared of any hydatid material which is confirmed by intra- operative choliangiography or choledochoscopy. After evacuation of hydatid elements from the biliary tree, either side to side choledochoduodenostomy or external T-tube drainage is done. Infection Suppuration of cysts takes place in 5 to 15 % of cases. The clinical picture resembles liver abscess and urgent surgery is necessary. Recurrence Incidence of recurrence is estimated to range from 8.5 % to 25 %. The causes of recurrence are peritoneal spillage and implantation during operations. New cyst formation from exogenous vesicles attached to the remaining pericyst after conservative treatment and reinfection.
  • Coexisting cholelithiasis Cholelithiasis exists with liver hydatid in three forms: true hydatid lithiasis, parahydatid lithiasis and accidential coincidence. In true hydatid lithiasis, histologic examination reveals the presence in central part of the stones of hydatid elements that constitute the lithogenic nidus. The parahydatic lithiasis is attributed to the abnormal delay in passage of bile into gallbladder provoked by an adjacent hydatid cyst. INVESTIGATIONS Routine laboratory tests are rarely abnormal occasionally eosinophilia may be present. Serum alkaline phosphatase levels are raised in one third of patients. Immunological tests Serological tests detect specific antibodies to the parasite and are the most commonly employed tools to diagnose past and recent infection with E. granulosus. Detection of IgG antibodies implies exposure to the parasite, while in active infection high titres of specific IgM and IgA antibodies are observed. Detection of circulating hydatid antigen in the serum is of use in monitoring after surgery and pharmcotherapy and in
  • prognosis. ELISA is used most commonly, but alternate techniques are counter-immuno-electrophoresis and bacterial co-agglutination. Elisa techniques have a high sensitivity above 90% and are useful in mass scale screening. The counter-immuno-electrophoresis has highest specificity (100%)and high sensitivity (80 – 90%). CASONI TEST It has been used most frequently in the past but this cutaneous hypersensitivity reaction using hydatid fluid is at present considered only of historical importance. The allergen is rarely standardized and infestation with other helminthes particularly cestodes can give a false positive response. Imaging techniques Plain abdominal radiography may reveal calcification, hepatomegaly, or indirect evidence of an hepatic SOL. (for eg. Elevated hemi diaphragm, right lung basal collapse, and pleural effusion). A coincidental lung cyst may be picked up on a plain skiagram. Ultrasound – is 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. Gharbi Classification on ultrasonographic features of Hydatid Cyst3
  • Type Ultrasound Appearance I Pure fluid Collection II Fluid collection with a split wall III Fluid collection with septa IV Heterogeneous echo pattern V Reflecting walls Type V cysts determined by ultrasound to be calcified and have been assumed to be dead cysts and do not require surgery. Computed Tomographic scan - has the highest sensitivity of imaging of the cyst (100%). 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. 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) – MRI delineates the cyst capsule better than CT scan, as a low intensity on both T1 and T2 weighted images. However CT scan is better in demonstration of mural calcifications, cysts less than 3 cm may not show any specific features and small peritoneal cysts may be missed. ASPIRATION CYTOLOGY Hydatid was considered to be a contraindication for FNAC. However, it may be used in diagnosis of hydatidosis if radiological studies reveal a
  • cyst and serological tests are equivocal. Diagnostic features include presence of laminated membrane, which gives a positive periodic acid schiff reaction, and a diagnosis of hydatid may be presumed. TREATMENT The treatment of choice is surgery. The principle of hydatid surgery are 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 operation7,8. All the surgical procedures can be divided into two large groups, conservative group and radical group. 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 (omentum is thought of fill residual cavity, to assist healing of raw surfaces and to promoted resorption of serosal fluid and macrophagic migration of septic focus)10, and suture
  • closure of the pericyst cavity after filling it with saline. Intracystic injections of scolicidal agents used in the past are formaldehyde solution, cetrimide solution 0.5%, hypertonic saline solution, 0.5% silver nitrate solution, and hydrogen peroxide solution. The arguments against the use of conventional intracystic solutions are: 1. In a large univesicular cyst, dilution of the scolicidal solution is unpredictable and impairs its efficacy. 2. If cyst communicates with the biliary system, it can lead to serious complications like sclerosing cholangitis and acute pancreatitis, have been reported with use of formaldehyde and hypertonic saline. Air embolism has been reported with the use of hydrogen peroxide. 3. Cetrimide solution produces severe adhesions formation. The best choice is silver nitrate solution 0.5% which has been reported to be safe and efficacious. The conservative surgical procedures are easy to perform but the postoperative complications and duration of hospital stay are not satisfactory.
  • Radical surgical procedures include cystectomy, pericystectomy, lobectomy and 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. Cystectomy – The procedure of choice is cystectomy. The procedure involves removal of hydatid cyst, comprising laminar layer, germinal layer and cyst contents i.e. daughter cysts and brood capsules. No attempt is made to remove the pericyst. The procedure is simple to perform and has low recurrence rates. 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 walls9. COMPLICATIONS OF SURGERY Biliary leakage is the most frequent postoperative complication following surgery for hydatid 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 third1. PERCUTANEOUS DRAINAGE OF HYDATID CYST Puncture of hydatid cysts have been discouraged in the past due to the potential risk of Anaphylactic shock and peritoneal dissemination. However, in the recent years percutaneous drainage has been used successfully to treat the hepatic hydatid cysts. Khuroo et al from India reported 88% disappearance of cysts with percutaneous drainage which was preceded by Albendazole therapy (10 mg/kg body weight) for 8 weeks5,6. 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. CHEMOTHERAPY FOR HYDATID DISEASE OF LIVER The compounds in clinical use are the benzimidazole derivatives (mebendazole and albendazole), which inhibit the uptake of glucose by the parasite and inhibit production of adenosine triphosphate, isoquinolone compounds (praziquantel) and immunostimulatory compounds: isoprinosine and trans-2- phenoxycyclohexonol ethers Mebendazole was the first drug to show any activity against hydatid cysts. It inhibits glucose uptake in susceptible parasites resulting in depletion of the worms energy sources and slow death. Its disadvantages are that it is poorly absorbed from the gastrointestinal tract. Although progressively higher doses for long periods have been given in an attempt to boost plasma concentrations, it has resulted in a plethora of side effects like prolonged fever, major liver disturbance, bone marrow depression and glomerulonephritis. It is no longer used in hydatid disease. Albendazole The principal metabolite, albendazole sulfoxide has antihelminthic activity
  • over a half-life of 8.5 hours. A dose of 10 mg/kg/day achieves an intra cyst concentration in excess of 100 ng/ml, which is within the effective scolicidal range. 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. Cure is defined as disappearance of the cyst, improvement is defined as > 25% reduction is size of cyst, membrane separation and appearance of calcification and deterioration as an increase in cyst size. As reported in study by Horton et al2 on 253 patients, cure rate was 32%, improvement was seen in 43%, 21% had no response and 1.5% patients showed increase in size of cyst. 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 is seen. Praziquantel increases the permeability of plasma membrane to calcium ions resulting in rapid loss and extreme contraction and paralysis of worms. Oral dose of 50 mg/kg/day for upto two weeks shows rapid scolicidal activity. Side effects are mild headache, dizziness, drowsiness, abdominal pain, and nausea. WHO has recommended the use of praziquantel preoperatively to achieve the sterilization of the cysts or postoperatively in cases of cyst rupture and spillage. Immunostimulatory compound Isoprinosine is an immunomodulatory drug, which appears to act via cytolytic effects on the cellular elements of the germinal layer, While the persisting superficial structures prevent the dissemination of viable cells. The drug has shown efficacy against E. granulosus and E. multilocularis in an animal model. References
  • 1. Kumar A, Lal BK, Chattopadhay TK. Hydatid disease of liver – Non-surgical options: J Assoc Physicians India 1993; Vol. 41. 2. Morris DL, Taylor DH, Optimal timing of postoperative albendazole therapy prophylaxis. Ann Trop Med 1988; 82: 65–66. 3. Gharbi HA, Hassine W, Brauner MW: Ultrasound examination of hydatid cyst liver, Radiology 1981; 139:459-463. 4. Menegelli UG, Martinelli LC, Angeles M. Polycystic hydatid disease (Echinococcus vogeli) clinical, laboratory and morphological findings in nine Brazilian patients. J Hepatology, 1992; 14:203-210. 5. Khuroo MS, Waini NA, Javid G, Khan BA. Percuatneous drainage compared with surgery for Hepatic Hydatid Cysts. N Eng J Med 1997; 13:337–400. 6. Palez V, Kugler C, Correa D, Carpio MD. PAIR as percutaneous treatment of hydatid liver cysts. Acta Tropica 2000; 75:197–202. 7. Agoglu M, DavidsonBR. A rational approach to the terminology of hydatid disease of liver. J .Infection 1992; 24:1–6. 8. Magistrelli P, Masetti r, Coppola R, Messia A. Surgical treatment of hydatid disease of liver: a 20 year experience. Arch Surg 1991; 126:518–523. 9. Saglam A. Laparoscopic treatment of liver hydatid cysts. Surg Lap Endosc 1996; 6:16– 21. 10. Dizri C, Paquet JC, Hay JM. Omentoplasty in the prevention of Deep abdominal complications after surgery for hydatid disease of liver: a multicenter, prospective randomized trial. J Am Coll Surg 1999; 188:281– 289.