The arthropathy of maintenance intermittent peritoneal dialysis

Among 61 patients undergoing maintenance peritoneal dialysis for an average of 20 months, 13 (21%) had a history of attacks of acute arthritis and 19 (31%) were found to have tender and often swollen joints. Deposits of calcium pyrophosphate dihydrate crystals in articular cartilage were identified in four patients and inflammation probably induced by hydroxyapatite crystals was noted in one. Periarticular calcification was observed in 12 patients and subperiosteal resorption of the phalanges in 20. The average calcium X phosphorus product was significantly higher (P < 0.025) in patients with a history of attacks of acute arthritis or with inflamed joints (58 +/- 12) than in those without (50 +/- 12). In the 19 patients whose treatment was changed to continuous ambulatory peritoneal dialysis there was a significant decrease (P < 0.025) in the calcium X phosphorus product but not in the proportion of patients with attacks of acute arthritis or with inflamed joints. The results indicate that articular complications are frequent among patients undergoing maintenance peritoneal dialysis and may be more common than with long-term hemodialysis.