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Percutaneous drainage of echinococcal cysts
  2. P A KAGER
  1. Division of Infectious Diseases
  2. Tropical Medicine and
  3. AIDS Academic Medical Centre
  4. Meibergdreef 9, 1105 AZ Amsterdam, the Netherlands
  5. Department of Radiology, Academic Medical Centre
  6. Meibergdreef 9, 1105 AZ Amsterdam, the Netherlands
  1. H G Schipper.h.g.schipper{at}

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Editor,—We read with interest the critical reply of Dr Morris (OpenUrlPubMed) to the letter on the use of PAIR (puncture, aspiration, injection, reaspiration) in the treatment of echinococcal cysts. He questioned the safety and efficacy of PAIR and wondered whether there was any other place for PAIR than in situations where surgery was not available. We comment on the risk of sclerosing cholangitis.

We agree with Dr Morris that injection of scolicidal agents into hydatid cysts is a potential risk for sclerosing cholangitis. However, this complication can be avoided when scolicidals are used for the correct indications. Scolicidals are not advocated at surgery because they have been associated with sclerosing cholangitis. The scolicidal probably enters pericystic liver tissue through breaks in the laminated membrane which cannot be identified by the surgeon's eyes.1 ,2 Therefore, in PAIR, as a standard procedure, cystography is performed before scolicidals are used.3Scolicidals can be safely instilled into the cyst if the laminated layer is intact and a cystobiliary fistula has been excluded. In our experience, cystography is only appropriate in Gharbi type 1 or type 2 cysts but not in type 3 cysts (so-called mother-with-daughter cysts). In type 3 cysts, the many daughter cysts prevent the injected contrast from reaching and demasking a possible fistula (fig 1; left). Therefore, we do not advocate the use of scolicidals in type 3 cysts.

Figure 1

Echinococcus cyst Gharbi type 3 in the liver dome of a patient. Left: The many daughter cysts which became apparent after injection of contrast into the mother cyst prevented reliable visualisation of a possible cystobiliary fistula. Right: Six weeks following percutaneous evacuation of the daughter cysts, a cystobiliary fistula was demonstrated by cystography.

Can patients with type 3 cysts be treated safely with percutaneous drainage? Faced with serious complications such as bile duct obstruction, cholangitis, rupture of cyst content into the biliary tree, sepsis due to cyst infection, and obstruction of portal and hepatic veins, we modified the PAIR procedure in these patients. After puncture and aspiration, the cyst content is evacuated via a 8–18 F catheter by frequent injection and reaspiration of small amounts of isotonic saline (20–40 ml) using a 60 ml syringe. The daughter cysts readily rupture when aspirated into the catheter. Puncture of each single daughter cyst is not necessary. We avoid injection of alcohol into the mother cyst because of the high occurrence of a cystobiliary fistula. Six of the 10 patients with type 3 cysts that we treated in this way had a cystobiliary fistula. In three the fistula was present before percutaneous aspiration was initiated. In the other three patients the fistula became apparent only after the procedure was completed (fig 1; right). In patients with type 3 cysts, scolicidals may therefore only be used, if at all, after percutaneous evacuation of all daughter cysts and subsequent exclusion of a cystobiliary fistula by cystography. Following the procedure we treat our patients with albendazole 800 mg at breakfast and dinner, for six months. During a follow up period of at least two years, ultrasound and serology are checked at regular intervals.

We do not share Dr Morris' opinion that the best indications for PAIR are only those where surgery is not available. Compared with surgery, PAIR of type 1 cysts is a simple procedure, less invasive, equally effective, and can be carried out in poorly equipped hospitals.4 ,5 Patients with type 3 cysts should be treated by experienced doctors in well equipped hospitals. Currently, most clinicians consider that surgery is the treatment of choice in these latter patients. However, the experience with percutaneous drainage as initial treatment of these complicated cases is growing. In the near future we will learn more about its pros and cons. An open mind for the clinical experience of the WHO working group and of others will be helpful in making up our minds.