Fogo, Ch. 12 - Diabetic Nephropathy Flashcards
How does diabetic nephropathy present?
Persistent albuminuria > Proteinuria > Renal failure (#1 cause of ESRD)
Distinguish between DN resulting from T1DM and T2DM.
Type 2 diabetes results in a usually less severe but more heterogeneous renal phenotype than Type 1.
What are the LM findings in early diabetic nephropathy?
Early enlargement (hypertrophy, corresponds to increased GFR.
What are the later LM findings in diabetic nephropathy?
GBM & Mesangial expansion; Diffuse or nodular (nodular is more specific)
Describe Kimmelstiel-Wilson nodules.
Usually focal and segmental PAS+ expansions that may be laminated.
What other nonspecific LM findings can be seen in diabetic nephropathy?
Globular hyalinosis (insudation), crescents (in less than 5%, consider ANCA)
What are the tubulointerstitial and vascular LM findings in diabetic nephropathy?
Tubular basement membrane thickening, can progress to fibrosis.
Arteriolar hyalinosis at the glomerular hilum.
What are the IF findings in diabetic nephropathy?
Linear IgG, kappa>lambda staining of GBM. Mesangial nodules also stain IgG.
What are the EM findings in diabetic nephropathy?
GBM thickening and mesangial matrix expansion. Protein insudate (not the same as an immune complex deposit!)
What is the utility of EM in diabetic nephropathy?
Useful to rule out other diagnoses like immunoglobulin deposition disease (granular densities) and fibrillary/amyloidosis (fibrillary deposits)
What defines class I diabetic nephropathy?
Mild/nonspecific
Some GBM thickening (>395/430nm)
What defines class IIa diabetic nephropathy?
Mild mesangial expansion, affecting >25% of glomeruli.
What defines class IIb diabetic nephropathy?
Severe mesangial expansion affecting >25% of glomeruli.
What defines class III diabetic nephropathy?
Presence of Kimmelstiel-Wilson nodules
What defines class IV diabetic nephropathy?
Global sclerosis, involving >50% of glomeruli.
What genetic loci are associated with diabetes?
RAGE promoter, DR3/DR4, ACE, ApoE
What is the outlook of diabetic nephropathy?
Slow progression, directly related to the degree of proteinuria.
Can be reversed with euglycemia?
How is diabetic nephropathy managed?
Treat the underlying diabetes. Give ACE/ARB. Can transplant, but disease often recurs.
How does ocular examination correlate with renal status?
Diabetic glomerulosclerosis is unlikely to develop in the absence of vascular changes in the eye fundus.
Summarize the pathophysiology of DN.
Nonenzymatic glycosylation of basement membrane, subsequent increased production or reduced degradation, hemodynamic abnormalities…
