Silent renal disease in systemic lupus erythematosus.

Several recent studies have focused on the discrepancy between lupus nephropathy and clinical renal involvement and, consequently, question the relevance of renal biopsy in these patients. We analyze the clinical characteristics, histological renal findings and subsequent course of patients with silent renal disease. Renal biopsy was performed in 15 patients with systemic lupus erythematosus (SLE) who had no clinical signs of renal involvement (no urinary sediment abnormalities, absence of proteinuria and serum creatinine less than 1.3 mg/dl). All biopsies were classified according to a modified classification proposed by the WHO. Six cases (40%) showed no histological or immunofluorescence changes (type I), 7 (47%) had mesangial nephropathy (3 type IIa and 4 type IIb) and 2 (13%) had focal proliferative glomerulonephritis (type III). None of the patients had previous evidence of neurological abnormalities. Patients with type I only had arthritis, skin lesions and Raynaud's phenomenon. By contrast, 7 patients with histological renal involvement had serositis or hemolytic anemia. All cases with silent nephropathy were treated with steroids and showed a benign clinical course with stable renal function and absence of urinary abnormalities during follow-up. We concluded that in the absence of clinical renal abnormalities, renal involvement is not uncommon in SLE. We believe that a renal biopsy should be performed mainly in those SLE patients presenting with clinical manifestations other than arthritis or cutaneous lesions since this policy may allow detection of significant silent renal injury.