AMYLOIDOSIS IN PATIENTS OF CONTINUOUS AMB ULATORY PERITONEAL-DIALYSIS

Dialysis amyloidosis is a common complication of long-term hemodialysi s. Amyloid deposits have been associated with carpal tunnel syndrome, bone cysts, pathological fractures, destructive spondyloarthropathy, a nd peripheral arthropathy, and it has been demonstrated that the amylo id protein is beta(2)-microglobulin. Carpal tunnel syndrome (CTS) has been reported to occur with a similar frequency in both hemodialysis a nd continuous ambulatory peritoneal dialysis (CAPD) patients. Radiolog ical bone lesions, similar to those described in HD patients with amyl oid arthropathy, have also been reported in patiens on CAPD. However, amyloid deposits in the carpal tunnel, synovial membrane or bone have been histologically proven in only a few CAPD patients. The main aim o f our study was to assess the prevalence of CTS and amyloid osteoarthr opathy in patiens on CAPD. We studied 20 patients, aged 38-82 years (m ean 58.8 years), who had been on peritoneal dialysis for between 2 and 88 months (mean 35.2 months), to investigate the prevalence of CTS an d amyloid osteoarthropathy. The diagnostic criteria for amyloid arthro pathy were: 1) histological confirmation of amyloid substance in synov ial fluid and/or 2) bone cysts on radiographs with a diameter greater than or equal to 5 mm in the wrist, and greater than or equal to 10 mm in the shoulder knee and hip, in at least two joints, which cannot be explained by any other pathological condition. Five patients (25%) we re found to have amyloid arthropathy, 2 of them had also CTS. Articula r and systemic amyloid deposits reacting with anti-beta(2)-microglobul in were demonstrated in 1 patient at necropsy. Patients with amyloid o steoarthropathy were significantly older (69.8 vs 55.1 years old) (p < 0.05) than those without osteoarthropathy, also the age at the onset of dialysis treatment was statistically higher 9 (65.4 vs 52.2 years o ld) (p < 0.05). The duration of dialysis treatment (48.2 vs 30.9 month s) and beta(2)-microglobulin levels (32.1 vs 25.7 mg/l) were not stati stically significant. The results suggest than amyloid arthropathy occ urs in patients on peritoneal dialysis even when dialysed for less tha n 5 years. Age at the onset of dialysis treatment and at time of asses sment appears to be a majors predisposing factors in the development o f amyloid osteoarthropathy.