[Renal manifestations in rheumatoid arthritis and spondylarthritis].

As systemic diseases it is not uncommon for inflammatory rheumatic diseases to exhibit renal involvement. In contrast to connective tissue diseases and vasculitis, in rheumatoid arthritis and spondylarthritis direct inflammatory manifestations in the sense of glomerulonephritis (GN) and autoimmune interstitial nephritis are rare. In these groups of diseases renal biopsies usually show mesangial proliferative GN and IgA nephropathy or less commonly membranous GN. These and secondary amyloid A (AA) amyloidosis are regularly associated with longer lasting disease activity and a poor prognosis; however, clinically more frequent and more relevant are other sequelae of chronic systemic inflammation, namely endothelial function disorder and the premature development of atherosclerosis, resulting in progressive kidney failure. This is accompanied by the undesired effects of antirheumatic treatment and renal complications of comorbidities.