Vesicoureteral reflux, chronic pyelonephritis and reflux nephropathy

Know the conditions that cause vesicoureteral reflux

• Maldevelopment – shortening of intramural portion of ureter due to abnormal embryologic development of an ectopically located ureteric bud with laterally displaced ureteric orifices.

• Obstruction – causes increased pressure

  • Organic causes

    • Bladder tumor

    • Prostate tumor / hypertrophy

    • Stones

  • Functional causes

    • Spinal cord injury

• Infection w/ mucosal edema

  • Intravesical ureter can’t function as an efficient valve

• Genetic factors

  • Male:Female ratio 5:1

  • Primarily a disorder of whites

  • Autosomal dominant, familial

  • Multiple genes exert a cumulative effect to reach a critical threshold for manifestation of reflux disease

Know the causes of renal reflux and reflux nephropathy

• Basically the same as (and including) VUR

• Allows spread of infection from lower urinary tract to kidney → pyelonephritis

• Subsequent intrarenal reflux leads to inflammation, scarring, and pelvocalcyceal deformity

• Sterile reflux may even cause damage – especially high-pressure VUR

Where are the potentially refluxing papillae in the kidneys?

• Usually located at poles

• Identified by concave surface and gaping orifices

Know the pathology of chronic pyelonephritis

• Kidneys tend to be reduced in size – unequally if bilateral

• With obstruction, there are scars with thinning of renal tissue overlying dilated calyces

• Solidification and / or hyalinization of capillary tufts

• Periglomerular fibrosis or deposition of collagen in Bowman’s capsule

• Tubular atrophy w/ eosinophilic casts (thyroidinization)

• Chronic inflammatory infiltrate in tubulointerstitium, pelvis, and calyces

• Xanthogranulomatous pyelonephritis

• Gross – Yellowish, nodular, and large lesions

• Micro – Foamy histiocytes, other acute and / or chronic inflammatory cells

• Usually associated w/ Proteus infection

Know the clinical manifestations of chronic pyelonephritis

• Recognition of chronic pyelonephritis is w/ radiologic exam, NOT biopsy

• Back pain, HTN, fever, bacteriuria, pyuria, proteinuria

• X-ray – Kidneys asymmetrically smaller, coarse scars overlying blunted papillae, deformed and dilated calyces

Category: Pathology Notes