[1650] Diabetic Nephropathy with an Atypical Clinical Course: A Potentially Treatable, Second Disease Is Commonly Found on Renal Biopsy

Patrick D Walker, Larry Nicholas Cossey, Josephine M Ambruzs, Fred S Silva. Nephropath, Little Rock, AR; University of Arkansas for Medical Sciences, Little Rock, AR

Background: Diabetes mellitus (DM) is now a world wide epidemic and diabetic renal disease is a significant cause of morbidity and mortality. Increasingly, renal biopsies are performed on atypical cases of diabetic nephropathy (DN) to look for treatable secondary causes of renal injury. The aim of this study was to determine the nature and prevalence of medical renal diseases occurring on a background of diabetic nephropathy (DN).
Design: Our surgical pathology database was searched for all non-transplant renal biopsies with DN over the last eleven years. 5289 had a diagnosis of DN accounting for 15.7% of all renal biopsies from that time period. These cases were evaluated for diagnoses in addition to DN. Each case was examined by light microscopy, immunofluorescence microscopy and electron microscopy using standard techniques.
Results: Clinical indications for biopsy included: acute or rapidly progressive renal failure and/or, increased proteinuria and/or hematuria with or without RBC casts. A second renal condition was found in 47.2% of cases in addition to DN. Of the 47.2%, primary glomerular disease was the most common secondary diagnosis (45.3%) including: IgA nephropathy (7.8%), crescentic glomerulonephritis (GN) (4.3%) and acute proliferative GN (4.3%). Lupus, amyloid, fibrillary GN, minimal change disease, membranoproliferative GN and others were found in ≤ 5%. Tubulointerstitial conditions were also common with acute tubular injury in 40.34% followed by acute interstitial nephritis in 8.9%. Other conditions such as microscopic polyangiitis, IgG4 sclerosing disease, crystal nephropathy, cholesterol emboli et al were also seen (n ≤ 55 each).
Conclusions: The differentiation between DN alone and DN with other primary renal diseases is important when the clinical course is atypical. In this, the largest series to date and from centers across the US, we found that 47% of patients with an atypical course for DN have another medical renal disease with a second primary GN being the most common. This study supports the use of renal biopsy in patients with DM and an acute change in renal parameters to determine the presence of potentially treatable causes of altered renal function.
Category: Kidney (does not include tumors)

Monday, March 4, 2013 1:00 PM

Poster Session II # 239, Monday Afternoon

 

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