Renal Biopsy in Type 2 Diabetic Patients

Abstract

The majority of diabetic patients with renal involvement are not biopsied. Studies evaluating histological findings in renal biopsies performed in diabetic patients have shown that approximately one third of the cases will show pure diabetic nephropathy, one third a non-diabetic condition and another third will show diabetic nephropathy with a superimposed disease. Early diagnosis of treatable non-diabetic diseases in diabetic patients is important to ameliorate renal prognosis. The publication of the International Consensus Document for the classification of type 1 and type 2 diabetes has provided common criteria for the classification of diabetic nephropathy and its utility to stratify risk for renal failure has already been demonstrated in different retrospective studies. The availability of new drugs with the potential to modify the natural history of diabetic nephropathy has raised the question whether renal biopsies may allow a better design of clinical trials aimed to delay the progression of chronic kidney disease in diabetic patients.

Keywords: diabetic nephropathy; histology; kidney biopsy; type 2 diabetes.

Figure 1

Natural history of diabetic nephropathy. There is a poor correlation between renal function deterioration, degree of albuminuria and histological findings. UAER: Urinary albumin excretion rate; CKD: chronic kidney disease; ESRS: end stage renal disease; * mg/gr creatinine; ** mL/mint/1.73 m².

Figure 2

A patient with nephrotic syndrome, type 2 diabetes and hepatitis C virus associated crioglobulinemia. (a) Hematoxilyn-eosin at 100× magnification showing a glomerulus with mesangial expansion and another with glomerular thombi; (b) periodic acid Schiff (PAS) stain at 400× magnification of the glomerulus showing thrombi; (c) same glomerular section at 400× magnification stained with Masson’s trichrome (d) immunohistochemistry showing subendothelial C3 deposition in the glomerular lumen.