Renal Biopsy Findings of Diabetic Nephropathy in Pediatric Patients with Type I Diabetes Mellitus
Steven P Salvatore, Surya V Seshan. Weill Cornell Medical College, New York City
Background: Diabetic nephropathy (DN) occurs in 20-40% of type 1 diabetic patients with a prolonged natural course. Typically, the clinical symptoms of microalbuminuria, overt proteinuria and chronic renal insufficiency do not present until early adulthood, but in some pediatric patients, microalbuminuria or proteinuria may necessitate a renal biopsy.
Design: All native kidney biopsy records in our institution from 1995-2010 for pediatric patients, aged 17 and less, with clinical diabetes were reviewed. The pathologic features were classified (according to Tervaert et al JASN, 2010) and analyzed with clinical renal disease.
Results: Of the 6785 native kidney biopsies, 17 were pediatric diabetic patients, ranging from 10 to 17 years of age (mean 14) with a male:female ratio of 8:9. All patients had insulin dependent, type 1 diabetes, diagnosed from 4 to 12 years prior to the biopsy, mean 8 years. One 15 year old female had hypertension and one 12 year old male was on an ACE inhibitor. Three of the patients had poorly controlled diabetes, 2 with diabetic ketoacidosis. The clinical indication for biopsy was microalbuminuria in 7 patients, proteinuria in 7 (range: trace to 2.17g/day), hematuria in 1, and a decreased GFR in 2. The serum creatinine ranged from 0.3 to 0.9 mg/dL (mean 0.7). On biopsy, 16 of 17 showed diabetic glomerulopathy, Class I (isolated GBM thickening) in 5, Class IIa (mild diffuse mesangial (mes) expansion) in 8, Class IIb (marked diffuse mes expansion) in 1 and Class III (nodular mes expansion) in 1. Vascular sclerosis was seen in 9 patients: mild in 6 and moderate in 3. Arteriolar hyalinosis was present in 10. Four cases had superimposed glomerular disease, 1 IgAN, 1 post-infectious glomerulonephritis (PIGN), 1 membranous GN and 1 mes immune complex GN. Sixteen of the cases had minimal interstitial fibrosis (IF) and tubular atrophy (TA), from 0-20% (mean <5%), with one case of immune complex mes GN having 30%. Electron microscopy revealed GBM thickening, 375-1400nm (mean 675nm) with mes expansion in 10/16 (62.5%) and foot process effacement in 9 cases, ranging from 10-70%.
Conclusions: Pathological lesions of DN may be seen in a susceptible group of type I diabetic adolescents with microalbuminuria or frank proteinuria. These patients tend to have milder forms of DN, Class I to IIa glomerular lesions. Identification of parenchymal diabetic lesions may prompt more specific treatment strategies to potentially reverse or slow the progression of DN. Nearly ¼ of the cases were also found to have other renal diseases superimposed on features of DN.
Category: Kidney (does not include tumors)
Wednesday, March 21, 2012 1:00 PM
Poster Session VI # 297, Wednesday Afternoon