15. Renal Pathology G - Cox

• Tubulointerstitial Nephritis (TIN) - affect tubules and interstitium
• TIN - most is caused by bacterial infection
• Interstitial Nephritis - caused by nonbacterial origin
• acute pyelonephritis - suppurative inflammation of kidney

  • involve Lower UTI
• acute pyelonephritis - most common causative organism?

  • enteric gram negative rod - E coli
• What is the most common route of entry for bacteria in acute pyelonephritis?

  ascending infection of lower UTI
• Acute pyelonephritis - patho-mechanism

  1. obstruction of bladder
  2. urinary stasis
• acute pyelonephritis - can also be caused by vesicoureteral reflux

  • incompetence vesicoureteral orifice = retrograde flow allow bacteria to go into ureter
• acute pyelonephritis lab

  • bacteriuria
  • WBC cast only in tubules
• Acute Pyelonephritis - characteristic

  • necrosis + abscess formation in renal parenchyma
• Emphysematous Pyelonephritis (EPN) - intraparenchymal gas
• ** Emphysematous Pyelonephritis (EPN) - gas is located within parenchyma
• Pyonephrosis - pus in renal pelvis due to UT obstruction + pyelonephritis
• Papillary necrosis - combination of ischemic and suppurative necrosis

  • predisposing condition
  • DM
  • UT obstruction
  • analgesic abuse
• renal corticomedullary abscess associated with ascending infection
• Xanthogranulomatous pyelonephritis (XPN) - due to chronic nephrolithiasis

  • feature - lipid laden foamy macrophage
• ** XPN - staghorn calculus

  • struvite - mg2+ ammonium phosphate + calcium phosphate
  • associated with urease producing bacteria - proteus
• ** Malakoplakia - granulomatous disease

  • Characterized by von Hansemann - may be results of defective macrophage phagolysosomal function
• ** Malakoplakia - deposition of calcium and iron on residual bacterial glycolipid = Michaelis Gutmann bodies