Proteinuria in rheumatoid arthritis-drug-induced or amyloid?

SUMMARY Over a 5-year period 325 patients with rheumatoid arthritis received treatment with gold (162) or D-penicillamine (163). Thirty-eight (11-7%) developed proteinuria, which persisted in 10 patients; renal biopsies in these 10 patients revealed 6 cases of amyloid disease. These 6 cases illustrate the importance of investigation of rheumatoid patients developing proteinuria even when they are receiving potentially nephrotoxic drugs. Secondary amyloidosis is a well known complication of rheumatoid arthritis, usually coming to attention when proteinuria or impaired renal function are noticed. Reports of its incidence vary with the selection of patients and the methods of detection employed. Arapakis and Tribe ' found a 5 % incidence of amyloid on rectal biopsy in an un-selected group of patients with rheumatoid disease of greater than 3 years ' duration. Malstrom2 found amyloid in 19 % of specimens of periapical dental tissue from another unselected group of rheumatoid patients. Missen and Taylor,3 reviewing several collected series of necropsy studies on rheumatoid patients, found a 14 % incidence ofrenal involvement. In all these studies the diagnosis was made by Congo red staining, with further confirmation from thio-flavine T or methyl violet. The usual sites for biopsy are kidney, liver, gingiva, or rectal mucosa, while Westermark and Stenkvist4 have successfully used subcutaneous fat aspirates to diagnose second-ary amyloidosis. Proteinuria in rheumatoid arthritis, however, also commonly occurs as a complication of gold or D-penicillamine therapy. We report our experience over a 5-year period in patients with rheumatoid arthritis receiving antirheumatic therapy with gold or penicillamine under hospital supervision. Patients and methods A retrospective analysis was carried out from the records of all patients with rheumatoid arthriti