Sclerosing encapsulating peritonitis in rats induced by long-term intraperitoneal administration of antiseptics

Continuous ambulatory peritoneal dialysis (CAPD) is an effective long-term treatment for renal failure. Sclerosing encapsulating peritonitis (SEP) is a rare but devastating complication of CAPD and may be caused by long-term peritoneal antiseptic exposure. We examined the peritoneal injury resulting from daily inoculations of moderately high concentrations of the following antiseptics: povidone-iodine, Dakin's solution, Amuchina, and Ampercide. After 4, 8, and 12 weeks of daily intraperitoneal injections in rats, a 10% solution of povidone-iodine in dialysis fluid caused a condition that mirrors human SEP. Animals had poor early weight gain, and gross necropsy examination revealed intestinal adhesions and a mesothelium that was sclerotically thickened. From 4 to 8 weeks to 10% povidone-iodine-injected animals showed progressive conditions and the prevalence of multiple encapsulating adhesions increased from 0/6 to 4/4, p = 0.005. Marked visceral mesothelial thickening in the 10% povidone-iodine-injected animals was quantitated after 4, 8, and 12 weeks at 92.0 ± 11.6, 151.5 ± 28.8, and 206.0 ± 36.2 μm, respectively. Rats injected with dialysis fluid (controls) had normal-appearing mesothelial surfaces measured at 1.8 ± 0.2, 2.4 ± 0.2, and 2.2 ± 0.2 μm after 4, 8, and 12 weeks, respectively. The marked thickening of the mesothelium in the 10% povidone-iodine group compared with the controls was highly significant, p<10^-8. We conclude that povidone-iodine, the most commonly used antiseptic in CAPD, caused severe tissue injury, whereas other antiseptic solutions, Dakin's, Amuchina, and Ampercide, at the similar dilution did not appear to cause mesothelial injury. The amount of antiseptic peritoneal exposure that occurs with proper use of the CAPD connecting systems studied here is low. However, because the threshold dose of antiseptic that induces peritoneal injury is not known, CAPD connecting system design should attempt to minimize this exposure.