In a patient with long-standing type 2 diabetes, which glomerular structural change appears earliest and precedes the onset of microalbuminuria?

• A Thickening of the glomerular basement membrane ✓
• B Formation of Kimmelstiel-Wilson nodules
• C Global glomerulosclerosis of more than half the tuft
• D Subendothelial electron-dense immune deposits

Explanation

GBM thickening, driven by nonenzymatic glycosylation and altered matrix synthesis, begins within a few years of diabetes onset and precedes detectable albuminuria. Diffuse mesangial expansion follows, then nodular glomerulosclerosis and eventually global sclerosis. Immune deposits are not part of diabetic nephropathy; its deposits are hyaline material such as capsular drop and fibrin cap lesions, not immunoglobulin complexes.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.