Diabetic nephropathy

DIABETIC NEPHROPATHY

• Diabetic nephropathy occurs as a consequence of microangiopathic disease

• 30 – 40% of patients develop

• Early manifestation is microalbuminuria (albumin in urine between 30 – 300mg/day

• In 20yrs 75% of type 1 Db and 20% of type 2 Db develop end stage renal failure

• Grossly – kidney is contracted and reduced in size

• Microscopy 

• Three lesions encountered in kidney in Diabetic nephropathy are

  • Glomerular lesions

  • Renal vascular lesions principally arteriosclerosis

  • Pyelonephritis including necrotizing papillitis

• The most important glomerular lesions are –

  • Capillary basement membrane thickening

  • Diffuse mesangial sclerosis

  • Nodular glomerulosclerosis ( kimmelstiel-wilson lesion )

• Capillary basement membrane thickening

  • Thickening of basement membrane of glomerular capillaries leads to diabetic microangiopathy

  • Thickening leads to mesangial widening

  • Thickening of BM of capillaries starts at as early as 2 years

  • Later thickening of tubular basement membrane occurs

• Diffuse mesangial sclerosis

  • Lesion consists of diffuse increase in mesangial matrix

  • Initially there is mesangial proliferation but later mesangial increase is associated with overall thickening of GBM and matrix deposition of PAS positive material

  • As the disease progresses mesangial deposition takes nodular configuration

• Nodular glomerular sclerosis

  • Also known as “intercapillary glomerulosclerosis” or “Kimmelstiel-Wilson disease”

  • Glomerular lesions take the form of ovoid or spherical laminated nodules of matrix situated in the periphery of the glomerulus

  • Nodules are PAS positive and are surrounded by capillary loops

  • Nodular lesions are accompanied by accumulations of hyaline material in capillary loops or adherent to bowman’s capsules

  • As the disease advances individual nodules enlarge and compress capillaries, obliterating the glomerular tuft

  • Both afferent and efferent arterioles show hyalinosis

  • Later due to arteriole and glomerular lesions, kidney develops ischemia which leads to tubular atrophy, interstitial fibrosis and contraction in size of the kidney

• Renal atherosclerosis and arteriosclerosis

• Pyelonephritis  –

  • chronic inflammation of interstitial tissue is more common

  • Special pattern of acute pylonephritis is necrotizing papillitis (papillary necrosis)

Reference 

1. Anirban Maitra. The Endocrine system.In: Robbins and Cotran Pathologic basis of disease.9th edition.volume II.chapter 24. pp 1073-1141.