Parasite: Echinococcus granulosus
Patients selected for PAIR are treated with a benzimidazole for 4 days prior to therapy and then for at least 1 month after the procedure (1 month for albendazole, 3 months for mebendazole).
Method:
(1) The cysts are localized using ultrasonography.
(2) A needle is passed into the cyst and the contents aspirated.
(3) A protoscolicidal solution is injected into the cyst.
(4) After waiting >= 15 minutes the cysts are reaspirated to remove the solution.
Indications for PAIR therapy:
(1) patients with contraindications for surgery, including patient refusal
(2) cysts in liver, abdominal cavity, spleen, kidney and bones
(3) relapse after surgery
(4) failure to respond to chemotherapy
Cysts for which PAIR is appropriate:
(1) anechoic lesions > 5 cm in diameter
(2) Gharbi type I or II
(3) cyst with double laminated layer
(4) Gharbi type III cysts > 5 cm diameter (multiple septal divisions) except honeycomb-type
(5) multiple cysts > 5 cm in different liver segments
Contraindications for PAIR therapy:
(1) lung cysts
(2) inaccessible cysts
(3) superficial cysts that might spill when punctured
(4) cysts with multiple septal divisions ("honeycomb")
(5) cysts with echogenic lesions
(6) inactive or calcified cysts
(7) cyst communicating with biliary ducts
(8) contraindication to benzimidazoles (first 3 months of pregnancy, allergy, etc.)
(9) noncompliance with chemotherapy
(10) very small cyst
(11) patient refusal
