Sonographically guided percutaneous treatment of hepatic hydatid cysts: Long‐term results

Sonographically Guided PercutaneousTreatment of Hepatic Hydatid Cysts:Long-Term Results

Kemal Odev, MD,1 Yahya Paksoy, MD,1 Ahmet Arslan, PhD,2 Ersan Aygun, MD,3 Mustafa Sahin, MD,3

Serdar Karakose, MD,1 Mahmut Baykan, MD,4 Hilal Arıkoglu, MS,2 Faruk Aksoy, MD3

1 Department of Radiology, Selcuk University, Faculty of Medicine, 42080 Konya, Turkey2 Department of Medical Biology and Genetics, Selcuk University, Faculty of Medicine, 42080 Konya, Turkey3 Department of General Surgery, Selcuk University, Faculty of Medicine, 42080 Konya, Turkey4 Department of Microbiology, Selcuk University, Faculty of Medicine, 42080 Konya, Turkey

Received 1 October 1998; accepted 12 June 2000

ABSTRACT: Purpose. The purpose of this study was toevaluate the safety and efficacy of sonographicallyguided percutaneous drainage and irrigation of he-patic hydatid cysts.

Methods. Sixty-one patients with 84 hepatic hyda-tid cysts were treated using the puncture, aspiration,injection, and reaspiration (PAIR) technique undersonographic guidance. Patients with cysts larger than6 cm in diameter underwent PAIR followed by percu-taneous drainage (PAIR-PD). The cysts were sterilizedby the injection of 1 of 2 scolicidal agents, 20% hyper-tonic saline solution (38 patients) or 0.5% silver nitrate(23 patients). All patients underwent follow-up exami-nations for 1 month–6 years after aspiration. Clinicaland radiologic examinations and laboratory analyseswere performed every month for the first 6 monthsand then at 3-month intervals.

Results. Serial sonographic examinations revealeda heterogeneous echo pattern in 78 cysts (93%); a pro-gressive decrease in diameter in 76 cysts (90%); cal-cification of the cyst wall, cystic contents, or both in 10cysts (12%); and complete disappearance of 1 cyst(1%) in a patient who had been monitored for over 6years. Five patients developed urticaria, and 6 devel-oped fever. One patient developed a biliary fistula af-ter the first aspiration attempt. Two patients devel-oped infection of the cyst cavity after PAIR-PD andwere successfully treated with oral antibiotics. Ananaphylactic reaction developed in 2 patients and wassuccessfully treated with antiallergenic medication.No recurrence of hydatid disease after PAIR or PAIR-

PD was observed in any patient over the follow-upperiod of 72 months (mean, 26 ± 27 months).

Conclusions. Percutaneous drainage of hydatidcysts is a safe, effective, and reliable treatment. Anti-allergenic medication is required before PAIR or PAIR-PD. Both sclerosing agents, hypertonic saline and sil-ver nitrate solutions, gave excellent results. © 2000John Wiley & Sons, Inc. J Clin Ultrasound 28:469–478,2000.

Keywords: hydatid cyst; percutaneous treatment; hy-pertonic saline; ultrasonography; liver; silver nitrate

Abdominal hydatidosis, caused by the larvae ofEchinococcus granulosus, is the most com-

mon form of hydatid disease.1 The radiographic,radioisotopic imaging, sonographic, CT, and MRIappearances of various forms of hydatid cystshave been described in detail.1–5 Hydatid diseaseis usually asymptomatic but may cause symp-toms and even death, depending upon the extentof the disease. Abdominal sonographic screeninghas shown that, in sheep-raising regions, approxi-mately 2% of the population is infected with hy-datid disease.6 Although surgical excision re-mains the preferred treatment, it may bedangerous or impossible to perform under certaincircumstances, eg, the patient is old or in poorhealth, the lesion is a postsurgical recurrence,there is multiple-organ involvement, or the hyda-tid cyst is near an inoperable site such as a majorbiliary or vascular structure.6,7 Some reportshave indicated that percutaneous irrigation anddrainage of hydatid cysts are effective.6–8

Correspondence to: K. Odev

© 2000 John Wiley & Sons, Inc.

VOL. 28, NO. 9, NOVEMBER/DECEMBER 2000 469

The purpose of this study was to evaluate thesafety and efficacy of sonographically guided per-cutaneous drainage and irrigation of hepatic hy-datid cysts. Our study differs from previous onesin that it represents a relatively large series inwhich 1 of 2 scolicidal agents was used in eachpatient and cystic regression was determined bylong-term follow-up sonographic evaluations.

PATIENTS AND METHODS

From 1992 to 1998, a total of 84 hepatic hydatidcysts in 61 patients were treated at our institu-tion, with follow-up periods ranging from 1 monthto 6 years after treatment. The patients (14 malesand 47 females) were 7–75 years old (mean, 41 ±15 years). The major complaints at presentationwere dull pain (n 4 15) and abdominal distention(n 4 30). Sixteen patients were asymptomaticand were admitted to clinics for other reasons.Oral consent was obtained from all patients whounderwent treatment.

Five of the patients included in the study had ahistory of hepatic cyst surgery; another 2 had ahistory of pulmonary hydatid cyst surgery. Theresults of liver function studies were normal for28 patients.

All patients were examined with both sonogra-phy and CT. Real-time sonography was per-formed using an RT-X200 (GE Medical Systems,Milwaukee, WI) or an EUB 420 (Hitachi, Tokyo,Japan) ultrasound scanner and a 3.5-MHz con-vex-array transducer. Cysts were classified basedon their sonographic appearances as described byGharbi et al.9 Patients who had cysts with a hy-perechoic, solid sonographic appearance andwhose cysts had ruptured into the biliary tree,pleural cavity, or peritoneal cavity were excludedfrom the study. Sonographic and CT diagnoses ofhydatid cyst were confirmed by serologic tests.We performed Casoni’s intradermal test, indirecthemagglutination test (IHA), and enzyme-linkedimmunosorbent assay (ELISA) to measure E.granulosus-specific immunoglobulin (Ig) G levelsas well as IgM antibody titers and determine thepatient’s humoral immune response and E.granulosus infection.

Each cyst was treated using the puncture, as-piration, injection, and reaspiration (PAIR) tech-nique; cysts larger than 6 cm were treated usingPAIR followed by percutaneous drainage (PAIR-PD). The state of infection following PAIR orPAIR-PD was determined based on serologic E.granulosus-specific IgG antibody levels usingELISA (Serion ELISA classic Echinococcus IgG,Institut Virion, Serion GmbH, Wirsburg, Ger-

many). Serologic test and ELISA results wereevaluated as described by Wattal et al.10

Each patient received prophylactic treatmentwith oral albendazole (10 mg/kg/day) beginning48 hours prior to PAIR or PAIR-PD and continu-ing for 3–6 months after PAIR or PAIR-PD.

Fifteen minutes prior to PAIR or PAIR-PD,each patient received diphenhydramine (10–50mg/ml), an antihistaminic drug; hydrocortisonesodium succinate (100 mg) and midazolam (0.1mg/kg), both anxiolytics; and diazepam (0.5 mg/kg), a muscle relaxant. PAIR or PAIR-PD wasperformed aseptically after local anesthesia wasadministered at the puncture site. Cardiac andhemodynamic parameters were monitored con-tinuously during the procedure.

The locations of the cysts in the liver weresonographically determined in 3 scan planes. A14–16-gauge Teflon needle was used for each cystwith a diameter equal to or greater than 6 cm,and an 18–22-gauge needle was used for each cystwith a diameter less than 6 cm.

The PAIR procedure was carried out in 3 steps.First, a percutaneous approach was selected un-der sonographic guidance, with the transducercovered by a sterile plastic bag. An intercostalroute through the liver was chosen for the punc-ture whenever possible to minimize peritonealspillage. About half of the cystic fluid was thendrained to decompress the cyst. Second, about 50–60% of the aspirated fluid volume was replacedwith a scolicidal agent, either sterile 0.5% silvernitrate or sterile 20% hypertonic saline solution.The injected scolicidal agent was left in the cystfor 20 minutes, during which the patient wasrolled from side to side into various supine posi-tions at intervals of a few minutes to achieve ahomogeneous mixture of scolicidal agents andcystic fluid. Third, the cystic contents weredrained completely. The cystic cavity was thenirrigated fully with sterile serum physiologic so-lution in an amount determined based on the sizeof the cyst. In multivesicular cysts, each daughtervesicle was drained and irrigated as above witheither of the scolicidal agents.

Cysts less than 6 cm in diameter (59 cysts in 36patients) were drained only once. Cysts greaterthan 6 cm in diameter (25 cysts in 25 patients)were considered large, and the PAIR-PD tech-nique was used. For the PAIR-PD technique, aninitial PAIR procedure was performed, followedby the insertion of an 8-Fr pigtail catheter, sub-sequent irrigation with 1 of the scolicidal agents,and aspiration of the cystic cavity under sono-graphic guidance. We irrigated the cyst 4–5 timesdaily during the patient’s hospital stay, which for

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470 JOURNAL OF CLINICAL ULTRASOUND

PAIR-PD treatment usually lasted 5–7 days. Dur-ing that time, daily drainage decreased to 10 ml.Catheters were removed when daily drainage de-creased to less than 10 ml. Patients who under-went PAIR-PD were subsequently monitoredwith sonography. A cystogram, in which a con-trast agent (iopromide) was delivered through acatheter under fluoroscopic guidance, was ob-tained regularly to ensure that there was no com-munication between the cystic cavity and the bil-iary tract.

Drained material from each cyst was collectedand sent for cytologic and microbiologic examina-tion. The collected cystic fluid was centrifuged,supernatants were poured off, and the pelletswere layered on slides for microscopic examina-tion. The viability of scolices was immediately as-sessed microscopically using neutral eosin dye.11

The drained fluid was cultured for both aerobicand anaerobic microorganisms to check for infec-tion.

Most follow-up evaluations included clinicaland radiologic examinations and laboratoryanalyses. Chest radiograph, sonography, and to-tal-body CT were performed every month for thefirst 6 months after PAIR or PAIR-PD and every3 months thereafter. IHA tests were donemonthly for the first 6 months and then at about3-month intervals thereafter or as needed. ELISAwas performed at 12-month intervals. Test re-sults showing E. granulosus-specific IgG levelsbelow 10 IU/ml or IgM antibody titers of less than1:160 and improved sonographic findings consis-tent with those results were considered signs oftotal recovery and indications for discontinuingfollow-up examinations.

The values for cystic size before and after PAIRor PAIR-PD were expressed as means ± standarddeviations (SD). Analysis of variance, paired ttest, chi-squared test, and regression analysis ofthe percentage reduction in cyst size were doneusing a statistical software package (SPSS 8.0). Ap value below 0.01 was considered significant.

RESULTS

Initial sonographic examinations revealed 84 he-patic hydatid cysts in 61 patients. Sixty (71%) ofthe cysts were located in the right lobe alone, 18cysts (21%) were in the left lobe alone, and 6 cysts(7%) were in both lobes. Seventy-eight cysts (93%)were type I, 2 (2%) were type II, and 4 (5%) weretype III, based on the classification established byGharbi et al.9

All 84 cysts were successfully treated withPAIR or PAIR-PD. The initial diameters of the

cysts varied from 2 to 17 cm (mean, 6.3 ± 2.6 cm),and the corresponding volume of the aspiratedcystic contents ranged from 20 to 2,500 ml. Theamount of 0.5% silver nitrate or 20% hypertonicsaline solution introduced into the cystic cavitiesranged from 10 to 1,500 ml.

The sonographic appearances of the cystic cavi-ties following the procedure were the same forPAIR as for PAIR-PD. Detachment of the lami-nated membrane started immediately after PAIRor PAIR-PD (Figures 1A and 1B). Sonography re-vealed a collapsed cystic cavity after the reaspi-ration of the cystic content (Figure 1C). A tran-sient early increase and later decrease in thevolume of fluid reaccumulated in drained cystsoccurred in the early months of follow-up (Figures1D and 1E). A considerable reduction in cyst sizeand the resumption of a solid appearance was evi-dent after 3 months of follow-up (Figure 1E), andby 36 months, the totally resorbed cystic lesionappeared as a solid, pseudotumoral mass on so-nography (Figure 1F). Sonographic follow-upevaluations performed over a 48-month periodshowed that there was no cystic fluid reaccumu-lation (Figure 2).

All daughter vesicles of the 4 multivesicularhydatid cysts were also successfully treated withhypertonic saline solution using the PAIR proce-dure. Subsequent sonography of the 4 multive-sicular cysts showed pseudotumoral appearances(Figure 3) that could easily be confused with otherhepatic lesions, such as an abscess, an infectedcyst, resolving hematomas, congenital cysts, thenatural degeneration of daughter cysts, or hepatictumors.

The viability of scolices in the cystic contentswas microscopically checked immediately afterPAIR or PAIR-PD. The cystic fluid was again as-pirated for testing in the third and sixth monthsof follow-up. The fluid obtained from the hydatidcysts by sonographically guided fine-needle aspi-ration had an orange-juice–like consistency andcontained necrotic debris and nonviable scolices.

An anaphylactic reaction developed duringPAIR in 2 patients. Both were treated with intra-venous diphenhydramine (50 mg/ml). One ofthese patients developed peritoneal irritation andrelated abdominal pain and underwent a success-ful total cystectomy. After treatment with an an-tiallergenic medication, the second of these pa-tients underwent PAIR using hypertonic salinesolution. Urticaria developed 1 day after PAIR in5 patients; these patients responded well to intra-venous diphenhydramine (15 mg/ml). Six patientsdeveloped fever 48 hours after PAIR; the feverresolved without treatment within 12 hours. In 1

PERCUTANEOUS TREATMENT OF HEPATIC HYDATID CYSTS


patient, bile-stained fluid was aspirated at thefirst puncture from 1 of 4 cysts, suggesting a bil-iary fistula. This patient’s serum bilirubin levelwas 3 mg/dl. A catheter was placed inside thecyst, and bile-stained fluid was drained over 5days. The patient’s bilirubin level gradually re-turned to normal, and fluid drained from thecatheter became clear and decreased to less than10 ml/day after 5 days. Two patients developedinfection of the cyst cavity 1 month after PAIR-PD. These 2 patients were given oral antibiotics,

and catheters were placed in the cysts. The cystsize gradually decreased, and the catheters wereremoved when the volume of the daily drainagedecreased to less than 10 ml. These 2 patientswere monitored sonographically.

All symptomatic patients reported that theirpain was relieved and they were more comfort-able immediately after irrigation. Cystic massesthat were palpable in 30 patients prior to PAIR orPAIR-PD disappeared after the third follow-upsonographic examination. IHA titers for IgM and

FIGURE 1. PAIR-PD of 2 hepatic hydatid cysts. (A) Pre–PAIR-PD sonogram shows 2 unechoic type I (pure fluid collection) hydatid cysts, 1 in eachlobe of the liver. (B) Sonogram of the right lobe of the liver, obtained after aspiration of the cyst cavity, shows detachment of the laminatedmembranes from the pericyst. (C) Sonogram of both lobes of the liver, obtained after the completion of reaspiration, demonstrates the 2 collapsedlesions. (D) Sonogram obtained 1 month following percutaneous drainage shows an initial cystic-fluid reaccumulation and re-expansion of thecystic cavities. Echogenic pieces of the linear membrane are seen floating in the reaccumulated hydatid fluid.

ÖDEV ET AL


ELISA results for IgG antibody levels decreasedover time. Of 30 patients who were tested 6–12months after PAIR or PAIR-PD, 12 had IHA titersbelow 1:160 and 14 had IHA titers that were 1:160 or higher but that had decreased from levelsof up to 1:16,000. Of 31 patients who were tested18–24 months after PAIR or PAIR-PD, 18 hadIHA titers below 1:160 and 5 had IHA titers thatwere 1:160 or greater but that had decreased fromlevels of up to 1:16,000. The remaining 12 pa-tients had IHA titers below 1:160 before the pro-cedure. On follow-up 1–72 months after PAIR orPAIR-PD, ELISA results for IgG antibodies werepositive (>15 IU/ml) in 23 patients, borderline(10–15 IU/ml) in 18 patients, and negative (<10IU/ml) in 20 patients; and IHA titers for IgM weregreater than 1:160 in 10 patients and 1:160 or lessin 51 patients.

Chest radiography, sonography, and total-bodyCT revealed no secondary vesicle formation, aprogressive decrease in all cyst diameters, andthe collapse of all cysts. Follow-up sonographicexaminations revealed a decrease in fluid contentand cyst size in 76 cysts (90%) and the completedisappearance of 1 cyst (1%) (Table 1). Seventy-eight cysts (93%) were obliterated, yielding a het-erogeneous echo pattern with a pseudotumoralappearance (Table 1). Calcification of the cystwall, intracystic contents, or both were found in

10 cysts (12%) (Table 1). The reduction in cyst sizewas slow and depended upon the time elapsedafter PAIR or PAIR-PD. The complete disappear-ance of a hepatic cyst occurred in only 1 patientand took 6 years (Table 1). No patient had a re-currence of hydatid disease after PAIR or PAIR-PD over a follow-up period of 72 months (mean,26 ± 27 months).

The comparative cost-effectiveness of the per-cutaneous (PAIR and PAIR-PD) and surgicaltreatments is shown in Table 2. The costs of hos-pital stays, health-care services, and surgical in-tervention are based on the fees at governmenthospitals for the public; these fees are fixed by theTurkish government and are the same through-out the country. The fees at private hospitals varyregionally but are usually several times higherthan the fees set by the government. Based on thegovernment’s fixed fees, percutaneous treatmentis 7–13 times less expensive than surgical treat-ment (Table 2).

Patients treated with either PAIR or PAIR-PDwere able to resume normal daily activities im-mediately after discharge from the hospital.

DISCUSSION

The results of our study show that the percutane-ous drainage of hydatid cysts using the PAIR or

FIGURE 1. (Continued) (E) Sonogram of the right lobe of the liver demonstrates a reduction in the size of the cyst (from 150 mm to 55 mm) 3 monthsafter PAIR-PD. Note that the cyst has the echogenic appearance of a semisolid mass. (F) Sonogram of both lobes of the liver shows the solid,pseudotumoral appearance of the cysts 36 months after PAIR-PD.



PAIR-PD technique is a safe and effective treat-ment.

Surgery is often the only treatment consideredfor hydatid disease.6,7 Surgical removal of thecysts is occasionally difficult or impossible and

FIGURE 2. PAIR of hepatic hydatid cysts. (A) Sonogram obtained be-fore PAIR shows 2 unechoic type I (pure fluid collection) hydatid cysts(70 × 67 mm) in the subdiaphragmatic area of the right lobe of theliver. Two daughter cysts (arrows) are also visible. (B) Sonogramobtained 24 months after PAIR shows a solid echogenic mass (ar-rows) due to resorption of cystic fluid. (C) Sonogram obtained at a48-month follow-up examination shows no reaccumulation of fluid inthe lesions (arrows).

FIGURE 3. PAIR of multivesicular hepatic hydatid cyst. (A) Sonogramof the right lobe of the liver shows a type III hydatid cyst before PAIR.Multiple daughter cysts, visible on the sonogram, were aspirated in-dividually. (B) Sonogram obtained 18 months after PAIR shows thatthe cystic cavity was obliterated. Note the echogenic structures (ar-rows). D, diameter; R, right.

TABLE 1

Sonographic Appearance of Hydatid Cysts Following PAIR

or PAIR-PD

Sonographic ChangeNo. Cysts (%)

(N = 84)No. Patients (%)

(N = 61)

Decrease in cyst size 76 (90) 57 (93)Heterogeneous echo pattern 78 (93) 59 (97)Calcification of cyst wall

and/or cystic content 10 (12) 3 (5)No change in cyst morphology 0 (0) 0 (0)Disappearance of cyst 1 (1) 1 (2)

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often leads to morbidity, dissemination of viablescolices elsewhere in the body, or both.7 More-over, the proximity of major biliary or vascularstructures may discourage surgical intervention.7

Surgical techniques such as partial pericystec-tomy or deroofing of the cyst, however, risk dis-seminating the cystic contents.7

The morbidity and mortality rates followingsurgical treatment for hepatic hydatid cysts varydepending upon the degree of liver involvementand the technique used for treatment. The mor-tality rates range from 1.1% to 6.3%,12 and thepostoperative complication rates range from12.5% to 80%.12,13 The length of the hospital stayfor surgically treated patients also varies. Thehospital stay following surgery can range from 7days for patients without complications to 30 daysfor patients with biliary fistulae, abscesses, or in-fection.14 The length of the hospital stay is alsoaffected by the surgical technique that is used.12

Percutaneous treatment shortens the length ofhospitalization considerably; most patients aredischarged within 48 hours after PAIR.

It may take a year for surgically treated pa-tients to resume normal daily activities, depend-ing upon the extent and number of surgical pro-cedures. Patients who undergo multiple surgicalprocedures are sometimes permanently disabled,an outcome that does not occur with percutaneoustreatment. Percutaneous treatment may be espe-cially advantageous for diabetic patients with he-patic hydatid cysts because the incision is mini-mal and the patients heal faster.

Hydatid disease is considered to have recurredif follow-up sonography and CT show either thegrowth of daughter vesicles within the principal

cyst or new cysts in the neighboring tis-sues.12,13,15 In the past, postoperative screeningfor recurrences was done by physical examinationand radiography; these methods, however, wereinsufficient for accurate assessment of recur-rences.16 Advances in imaging techniques and theroutine use of sonography and CT during follow-up have revealed that the postsurgical recurrencerate is actually higher than 11%,16 ranging from18% to 30%.17–19 By comparison, a recurrencerate of 3–4% was reported after percutaneoustreatments,6,20 confirming the effectiveness of theprocedure. During the 6 years of follow-up in ourseries, we did not observe any recurrences, re-gardless of whether the patient had been treatedwith hypertonic saline solution or silver nitratesolution.

On both postsurgical and post-percutaneoustreatment sonograms, the hydatid cysts havepseudotumoral appearances. The loss of the char-acteristic sonographic appearance of hydatidcysts makes it difficult to distinguish these le-sions from other hepatic lesions.17 With surgicalintervention, the cystic contents are evacuatedand the residual cavity is filled by omentoplasty,ie, introducing into the cavity a piece of viableomentum, which is supported by a few absorbablesutures placed between the pericystium andomentum to prevent displacement; by the intro-flexion of the adventitia into the cavity; or by bothmethods.17–23 Postoperative sonograms show theomentoplasty as a smooth, hyperechoic mass (Fig-ure 4A),17 and CT scans show it with a distinct,smooth surface with negative attenuation values,which can be attributed to the fat content of theomentoplasty (Figure 4B).21,22 Sonograms of cystsafter PAIR or PAIR-PD show a diffusely hetero-geneous echo pattern with a pseudotumoral ap-pearance that may be erroneously interpreted ashepatic tumors (Figures 1F, 2C, and 3B) or con-fused with other cystic lesions, such as abscesses,infected cysts, resolving hematomas, congenitalcysts, and naturally degenerating daughter cysts.However, this pseudotumoral pattern graduallydecreases in size and becomes indistinguishablefrom the liver parenchyma 4–5 years after PAIRor PAIR-PD.

Anthelmintics such as albendazole, mebenda-zole, and praziquantel may be effective in treat-ing hydatid disease. In our series, anthelminticdrugs were routinely used beginning 48 hoursprior to PAIR or PAIR-PD and continuing for 3–6months after the treatment, to prevent recur-rence from spilled cystic contents. To explain whymedical treatment may be effective in some butnot all cases, a comparative in vitro study was

TABLE 2

Cost-Effectiveness of Percutaneous and

Surgical Treatments

Item

PercutaneousTreatment

PAIR PAIR-PD Surgery

Hospital stay, days 2 5–7 7–15Additional hospital stay due to

complications, days — — 20–30Hospital-stay cost,*

in United States dollars 14 14–49 49–315Medical-care cost,

in United States dollars 50† 150‡ 1,200§

*Regulated and set by the Turkish government.†Includes disposable polyethylene needle, anesthetics, and medi-

cation for a single cyst.‡Includes 8-Fr pigtail catheter, anesthetics, and medication for a

single cyst.§Cost may be higher for cases in which there is multiple-organ

involvement.



performed, using the cystic fluids that were sur-gically removed from the patients.24 The effec-tiveness of hypertonic saline solution and of silvernitrate solution was microscopically determinedusing eosin-Y dye. The effects of hypertonic salineand silver nitrate solutions were apparent after20 and 60 minutes, respectively, and the effect ofalbendazole was apparent at 48 hours.24 The ef-fectiveness of saline and silver nitrate solutionscan be attributed to the irreversible destruction ofscolices in cystic fluid and the protoscolex contentof the germinative membrane.24 The delayed ef-fect of the albendazole and the regrowth of cystsafter oral albendazole treatment may be attrib-uted to the fact that this treatment was effectiveonly in destroying scolices in the cystic fluid. Thegerminative membrane was apparently not com-pletely destroyed; the cystic regrowth that oc-curred must have come from the protoscolices ofintact germinative membrane.24

The work of Bezzi et al15 and Todorov et al25

further supports our hypothesis. In our experi-ence, oral albendazole treatment has clearlyeradicated uncomplicated hydatid cysts in thelungs. Similar results for lung hydatid cyst treat-ment were also reported by Todorov et al.25 How-ever, treatment of liver hydatid cysts by oral an-thelmintic medication yielded inconclusiveresults.25 We concluded that the differential effectof albendazole in lung and liver hydatid cysts maybe due to inactivation of the oral albendazole inthe liver, although the direct use of albendazolesolution as an irrigation agent at the site appearsto be an alternative treatment for liver hydatidcysts. Still, the poor solubility of anthelminticdrugs remains a problem when using these drugsfor percutaneous treatment.

The possible dissemination of daughter cysts tothe neighboring tissues and the strong antigenicproperties of spilled cystic fluid were the majorconcerns in using PAIR or PAIR-PD for hydatiddisease treatment.6,20,26,27 In a study by Schiller,28

2 of 3 patients with ruptured hydatid cysts diedwithin 48 hours as a result of tachypnea, tachy-cardia, and hypotension. As shown in our study,minor complications such as fever, urticaria, andhypotension can develop20,29–31 during percutane-ous treatment; therefore, it is recommended thatan antiallergenic cocktail be administered to thepatient prior to PAIR as a precaution.

Akhan et al20 observed that the use of a cath-eter rapidly reduced the size of large cysts andcaused the collapse of the detached laminatedmembranes. In our study, PAIR was used forcysts less than 6 cm in diameter, and the cystswere drained at once. For larger cysts, we used

FIGURE 4. Surgically treated hepatic hydatid cysts. (A) Sonogram ofthe left lobe of the liver obtained after partial cystectomy and omen-toplasty shows a hyperechoic mass (arrows) within the liver tissue.To differentiate a mass with this sonographic appearance from otherhepatic lesions, the patient’s medical history is needed. KC, liver(Turkish). (B) Contrast-enhanced CT scan obtained 12 months afteromentoplasty shows a smooth-contoured residual cystic cavity dur-ing follow-up. Negative attenuation values of fat tissue on CT scansare typical of omentoplasty.

ÖDEV ET AL


the PAIR technique initially to reduce internalpressure in the cystic cavity, and an 8-Fr pigtailcatheter was then inserted into the cavity. Thecystic cavity was then irrigated with a scolicidalagent and drained for 5–7 days. This proceduredestroyed potentially viable germinative mem-branes and viable scolices. Multivesicular cysts(type III) can also be treated successfully byPAIR,20,26 as was done with the 4 type III cysts inthis study.

A number of scolicidal agents, including forma-lin, silver nitrate (0.5%), cetrimide (5%), hyper-tonic saline solution (10–20%), alcohol (95%), hy-drogen peroxide, and iodine (1%), have been usedduring surgical intervention to prevent dissemi-nation of leaking cystic fluid and spillage of thecontents of the cyst.6–8,26,30–35 Filice et al35 statethat alcohol is more effective than hypertonic sa-line over the long-term. However, we found thatin in vitro applications, both alcohol and hyper-tonic saline are effective within 20–60 minutes,whereas silver nitrate has a relatively delayed ef-fect.24 It was also reported that scolicidal agentscause inflammation of the biliary system.33,34,36,37

Formalin and alcohol were reported to have thestrongest inflammatory effects, hypertonic salineand cetrimide had intermediate effects, and silvernitrate cause the least inflammation or late stric-ture formation.36

Cure of hydatid disease depends on the abso-lute destruction of the germinative membrane.Exposure of the cystic cavity to scolicidal agentsfor 20 minutes not only had a scolicidal effect onthe cystic fluid but also was sufficient to destroythe protoscolices of the germinative membraneand cause detachment of the germinal membranefrom the pericyst.24

Immediately after PAIR, omentoplasty, and in-troflexion, a temporary cystic fluid reaccumula-tion occurs within the first month of follow-up.The reason for this occurrence is unknown. How-ever, during this time of inflammatory response,IHA titers and IgM antibody levels also remainhigh. As a corollary to the decline in IHA titersand IgM antibody levels, the fluid reaccumulationand cystic re-expansion decline gradually over 3months. The cystic cavities, then completely de-void of fluid, collapse totally after 1 year, givingrise to a pseudotumoral sonographic appearance.The IgG antibody levels in patients who have hadE. granulosus infection can remain at reduced(borderline) levels for several years. We believethat a negative IgG level may be an indication ofcomplete healing. Additionally, a decrease in cystsize, the disappearance of the cyst, an irregularityof the cystic sonographic appearance, cystic-wall

thickening, a pseudotumoral sonographic appear-ance with a heterogeneous echo pattern, calcifica-tion of the cyst wall or the cystic contents, and theloss of the antigenic properties of the parasite aregood indications of the effectiveness of the treat-ment. In our series, partial changes in cystic le-sions and the persistence of antigenic propertieswere considered to be indications of partial suc-cess, and continued follow-up is indicated in suchcases. Conversely, an increase in cyst size, thepresence of daughter cysts in the cyst cavity, andan elevation in Ig titer levels would be consideredindications that the treatment failed. We have ob-served no indications of failure after PAIR orPAIR-PD procedures in over 6 years of patientfollow-up in this study.

In conclusion, sonography, CT, and laboratoryanalyses obtained during follow-up revealed thatsonographically guided PAIR and PAIR-PD areeffective, safe, and reliable in the treatment ofsymptomatic and asymptomatic hydatid disease.PAIR and PAIR-PD are also more cost-effectivethan surgery. PAIR or PAIR-PD is especially rec-ommended in cases in which surgical treatment iscontraindicated, in cases of hydatid disease withmultiple-organ involvement or recurrent diseaseafter surgery, and for patients who refuse sur-gery. To prevent possible side effects of percuta-neous treatment, such as anaphylaxis, antialler-genic medication should be given prior to PAIR orPAIR-PD.

ACKNOWLEDGMENTS

We acknowledge the kind assistance of Dr. SaitBodur, Dr. Kemal Tahir Sahin, Dr. Mustafa Bu-lun, Dr. Mustafa Ozyoruk, Melda Aksoy, and BigeArslan with the statistical analysis and of MarniElci in editing the English text. ELISA tests forIgG were supported by the Faculty of MedicineResearch Fund.

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4. Beggs I. The radiological appearances of hydatiddisease of the liver. Clin Radiol 1983;34:555.

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Sonographically guided percutaneous treatment of hepatic hydatid cysts: Long‐term results