[1652] Non-Nephrotic Range Proteinuria in Asymptomatic Children

Sharon Wu, Gina Ragsdale, Abanti Chaudhuri, Neeraja Kambham. Stanford University, Stanford, CA; Stanford Hospital and Lucille Packard Children's Hospital, Stanford, CA

Background: Persistent mild proteinuria in otherwise asymptomatic children may be the initial presentation of significant renal disease. The clinical management and the threshold for performing a renal biopsy can be difficult to determine. Retrospective review of such cases may provide insight into the anticipated histologic abnormalities and their clinical course may suggest therapeutic guidelines.
Design: Renal biopsies from asymptomatic children with non-nephrotic range proteinuria {urine protein creatinine ratio (uP/Cr) < 2}, ± microscopic hematuria, were identified in our pathology database over a ten-year period (2000-2010). Of these, adequate biopsies with nonspecific diagnoses were further evaluated for clinicopathological parameters.
Results: 52 patients with asymptomatic non-nephrotic range proteinuria were identified and 24 (46%) had non-diagnostic pathology. Other diagnostic categories included FSGS (19%), Alport's syndrome (11%), nonspecific immune complex-mediated disease (7.7%), IgA nephropathy (5.7%), membranous nephropathy (3.8%) and thin basement membrane disease (5.7%). The mean uP/Cr in the “non-diagnostic” category patients was 0.8 (range 0.05-1.9). 9 patients had associated persistent microscopic hematuria. All had normal renal function with mean GFR of 149±41 ml/min/1.73 m2, negative serological studies and normal serum complements. Histological findings were unremarkable except for minimal global glomerulosclerosis (< 3%) in seven patients. Interestingly, 4 cases demonstrated diffuse foot process effacement (FPE) which in light of only mild proteinuria was interpreted as asymptomatic minimal change disease (MCD). Only one such patient subsequently developed a full clinical picture of MCD in a couple of weeks, requiring steroid therapy. 50% of the patients received angiotensin converting enzyme inhibitors. On follow up (mean follow up 47 months; range 1-118 mo), all patients had stable renal function, 14 (58%) had resolution of proteinuria and 10 (42%) had reduced, yet persistent proteinuria (mean uPr/Cr 0.45; range 0.05-1.38); 3 developed hypertension requiring treatment.
Conclusions: Asymptomatic pediatric patients with non-nephrotic range proteinuria and non-specific renal biopsy findings have a benign clinical course. Ultrastructural diffuse FPE in such a setting may represent evolving MCD and requires close clinical follow up.
Category: Kidney (does not include tumors)

Monday, March 4, 2013 1:00 PM

Poster Session II # 245, Monday Afternoon


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