Kidney nontumor


Chronic pyelonephritis

Topic Completed: 3 December 2012

Minor changes: 18 June 2021

Copyright: 2002-2021,, Inc.

PubMed Search: Chronic pyelonephritis [title] kidney

Nikhil Sangle, M.D.
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Cite this page: Sangle N. Chronic pyelonephritis. website. Accessed December 6th, 2021.
Definition / general
  • Chronic tubulointerstitial inflammation and renal scarring with severe involvement of calyces and pelvis
  • Pyelocalyceal damage / blunting rules out other tubulointerstitial inflammation
Clinical features
  • Causes 10% - 20% of end stage renal disease in transplant or dialysis units
  • Associated with pyelitis and ureteritis cystica
  • Some patients with pyelonephritic scars develop focal and segmental glomerulosclerosis with proteinuria in nephrotic range, perhaps due to renal ablation nephropathy

  • Types: reflux (chronic reflux-associated pyelonephritis) and obstruction (chronic obstructive pyelonephritis)
  • Reflux: more common, usually arises in childhood, unilateral or bilateral; damage often due to infection; associated with calyceal dilation (usually upper pole); see tubular atrophy and thyroidization, interstitial fibrosis
  • Obstruction: associated with parenchymal scarring, usually not in children
Case reports
Gross description
  • Irregular scarred cortical surface usually at poles, dilated and blunted calyces
  • Dilated ureter; retraction and destruction of papillae with "U” shaped scars
Microscopic (histologic) description
  • Tubular thyroidization (filled with colloid casts), tubular atrophy
  • Interstitial fibrosis and inflammation (intense diffuse lymphoplasmacytic inflammatory infiltrate with germinal centers)
  • Obliterative endarteritis of vessels, interstitial Tamm-Horsfall protein (amorphous, fibrillary, PAS+ material surrounded by inflammatory cells)
  • Normal glomeruli early in disease course
Microscopic (histologic) images

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Various images

Differential diagnosis
  • Chronic glomerulonephritis: diffusely scarred cortex
  • Vascular disease: can cause wedge shaped cortical scars, but underlying medullary and calyceal areas are normal
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