Clinical, radiological and serum amyloid P component scintigraphic features of beta(2)-microglobulin amyloidosis associated with continuous ambulatory peritoneal dialysis

Background. beta(2)-Microglobulin (beta 2M) amyloidosis occurs in patients with end-stage renal failure (ESRF) who undergo long-term continuous ambula tory peritoneal dialysis (CAPD), but its prevalence in patients treated exc lusively by CAPD is unknown. In addition, its features may differ from thos e of haemodialysis-associated beta 2M amyloidosis because CAPD is more bioc ompatible. Methods. We performed serum amyloid P component (SAP) scintigraphy, a speci fic technique for imaging amyloid deposits, in 13 consecutive patients with ESRF who had been dialysed for >5 years, at least 80% of the time by CAPD. Clinical and radiological features of beta 2M amyloidosis were sought and compared with the results of SAP scintigraphy. Results. SAP scans showed articular amyloid deposits in seven patients, all of whom had evidence of carpal tunnel syndrome and four of whom had arthra lgia characteristic of dialysis amyloidosis. Typical radiographic bone cyst s were present in only one case who had been dialysed for >17 years. The re maining six patients had no clinical, radiological or scintigraphic evidenc e of beta 2M amyloidosis. Conclusions. The prevalence of beta 2M amyloidosis in this study was compar able with that in reported haemodialysis populations. Many of the amyloid d eposits demonstrated by SAP scintigraphy were not associated with symptoms, but larger and longer term studies are required to determine whether CAPD favourably influences their clinical expression.