Steroid-sensitive nephrotic syndrome and juvenile idiopathic arthritis.

Abstract

Steroid-sensitive nephrotic syndrome · Juvenile idiopathic arthritisSirs,Secondary nephrotic syndrome (NS) and kidney involve-ment are common in adults with rheumatoid arthritis(RA). Nephropathy in patients with RA varies and couldbe due to RA itself and/or to anti-rheumatic therapy [1].Renal involvement usually occurs several years after thediagnosis of RA [2] and can present as glomeruloneph-ritis (mesangial, membranous, focal proliferative, andminimal change lesions), amyloidosis, or interstitial ne-phritis [1, 2]. Similarly, NS may complicate juvenile idiopathic arthritis (JIA) and has been described in adults[3], children [4], and infants [5] with JIA. In these pa-tients, it has been characterized by amyloidosis [3, 4, 5]and glomerulonephritis [6].We report a case of primary steroid-sensitive NS(SSNS) and JIA in which nephrosis preceded the devel-opment of JIA by years. A 2.5-year-old Serlankian girlpresented to King Abdul Aziz University Hospital withSSNS. She responded to steroid therapy, but demonstrat-ed a frequently relapsing NS. She was maintained on lowdoses of alternate-day prednisolone to prevent relapsesof NS. Four years later, at the age of 6.5 years, she pre-sented with monoarticular arthritis in the knee joint. Shehad left knee effusion that lasted for more than 6 months.Slit-lamp examination of her eyes revealed no abnormal-ities. At presentation of her arthritis, her erythrocyte sed-imentation rate was elevated at 96 mm/h, her comple-ment levels were normal, and anti-nuclear antibody andanti-DNA antibody titers were negative. Radiographsdemonstrated left knee effusion with slight enlargementof the left femoral epiphysis, thought to be due to chron-ic inflammation. Magnetic resonant imaging revealedmarked effusion in the left knee with features suggestiveof synovitis, but no cartilaginous or osseous lesions. Thepatient was diagnosed with monoarticular JIA after ex-cluding infection, as synovial fluid showed a normal cellcount and negative culture. A skin test for tuberculosiswas negative. She required intra-articular steroid injec-tions and oral naproxen to control her joint symptoms.Her NS continued in remission with minimum doses ofalternate-day prednisolone. Her height standard devia-tion score at 7.5 years of age was –0.16 and her bodymass index was 23.3.The clinical pattern in which childhood SSNS pre-cedes JIA is quite different from that described as sec-ondary NS complicating JIA or RA. Mesangial glomeru-lonephritis is commonly identified as the renal lesionwhen renal disease is described in adults with RA; thisconcurrence has been described in only one child withJIA [6]. Similarly, the minimal change NS (MCNS) le-sion has been described as a cause of NS associated withRA in adults, but not in children [1]. Secondary NS asso-ciated with chronic arthritis is usually steroid resistant,difficult to treat, and requires other immunosuppressivetherapies to achieve control [3]. Nephropathy complicat-ing RA usually occurs several years after the onset ofRA. Our patient presented with renal manifestations be-fore the onset of features of JIA. While the occurrence ofSSNS and JIA could be coincidental, it is possible thatchronic juvenile arthritis and MCNS share some com-mon pathogenic basis or mechanism [7]. Both conditionsare associated with T lymphocyte dysfunction, often trig-gered by viral infections, the production of circulatingfactor(s), and abnormal cytokine expression. Both condi-tions also seem to have genetic predisposition and link-age to HLA-DR antigens of major histocompatibilitycomplex type II. This patient represents the first reportedexample of a child with steroid-responsive NS who sub-sequently developed JIA.