Renal Lesions of Juvenile Idiopathic Arthritis in Children: A Literature Review

The literature review presents current data on the frequency, mechanisms of development, clinical manifestations, diagnosis and treatment of renal AA-amyloidosis and describes different forms of glomerulonephritis (GN) in children with juvenile idiopathic arthritis (JIA). The frequency of AA renal amyloidosis in JIA in children ranges from 0.8% to 2%, in adults with JIA duration of 28.3 years - 8.9%. In recent years, against the background of immunobiological therapy, the incidence of AA-amyloidosis of the kidneys in adults has decreased to 2%. AA-amyloidosis of the kidneys most often develops in children with the systemic form, in adults - with systemic and polyarticular forms of JIA. The first symptom of AA-amyloidosis of the kidneys is isolated proteinuria, which transforms into nephrotic syndrome. The peculiarity of the nephrotic syndrome is the absence of hypercholesterolemia in most cases, combined in some patients with arterial hypertension, hematuria, and impaired renal function. The available literature presents clinical cases of renal GN in children with JIA, viz: ANCA-associated GN, mesangioproliferative GN, including IgA- and IgM-nephropathy, membranous nephropathy, focal-segmental glomerulosclerosis, minimal change disease, extracapillary GN. Most publications are devoted to ANCA-associated HN, which developed in patients with a torpid course and a high degree of activity of polyarticular and systemic forms of JIA. The peculiarity of ANCA-associated HN was the presence of hypercreatininemia and, in almost half of cases, the development of terminal renal failure, despite the ongoing immunosuppressive therapy. The main method confirming the diagnosis of AA-amyloidosis and renal HN is the intravital renal morphological study. The use of immunobiological drugs in renal AA-amyloidosis and HN in children with JIA has therapeutic efficacy.