mindmap - Renal obstructions

Urinary Outflow Obstruction

• Renal stones
  • general characteristics
    • "urolithiasis" is calculus formation
      at any level in the urinary collecting system
      most often arising in the kidney
      very frequent - 1% of all autopsies
      men>women symptomatic urolithiasis
  • pathogenesis
    • types of stones
      • 80%
        • Ca-Oxalate
          • metabolic disorder
        • Ca-Oxalate plus Ca-Phosphate
      • 10%
        • magnesium ammonium
          phosphate (struvite)
          • urea-splitting organisms
      • 6-9%
        • uric acid
          • after chemotherapy
          • medications
            • salicylates
          • gout
        • cystine
          • hypercystinemia
          • inherited metabolic disorder
      causes of formation obscure
      the most important cause being
      increased urine concentration
      
      
      • supersaturation
      also, hypercalcemia very important
      • high Na diet
      • loop diuretic
      • cushing's
      • hyperthyrodism
      • vitD excess
      struvite almost always with UTI
  • morphology
    • stones unilateral in 80%
    • common site of formation
      • renal pelvis
      • calyces
      • bladder
    • huge stone - staghorn calculi
      • usually struvite
  • clinical course
    • stones may be present without symptoms
    • smaller stones more likely to produce symptoms
    • renal colic
      • flank pain
      • radiating toward groin
    • gross hematuria
    • may cause ulceration and bleeding
      • predisposing to UTI
    • may cause fluid retension
• hydronephrosis
  • general characteristics
    • dilation of renal pelvis and calyces
    • atrophy of parenchyma
    • caused by obstruction
      of urine outflow
      • sudden
      • insidious
    • common causes
      • congenital
        • atresia of urethra
        • valve formation
        • aberrant renal artery compressing ureter
        • renal ptosis with torsino
        • kinking of ureter
      • acquired
        • foreign bodies
          • calculi
          • necrotic papillae
        • tumours
          • BPH
          • Ca of prostate
          • Blatter tumour
          • Ca of cervix
        • inflammation
          • prostatitis
          • ureteritis
          • urethritis
          • retroperitoneal fibrosis
        • neurogenic
          • spinal cord damage
            with palaysis of bladder
        • normal pregnancy
          • mild and reversible
  • pathogenesis
    • even with complete obstruction, Glomerular Filtration goes on for some time
    • filtrate diffuse back into renal interstitium and perirenal space
    • ultimately return to lymph and veins
    • affected calyces and pelvis become dilated
    • high pressure transmitted back into the collecting ducts
    • compress renal vasculature
    • papillae most affected by pressure
    • inirial functional disturbance - impaired concentrating ability
    • later, glomerular damage occurs
    • serious irreversible damage with...
      • 3wks with complete obstruction
      • 3 months with partial obstruction
    • obstruction also triggers interstitial indlammatory reaction
      • fibrosis of interstitium
  • morphology
    • bilateral hydronephrosis
      • uremia
      • renal dailure
      • bladder distension and hydroureter
    • unilateral
      • massive kidney
      • obliteration of papillae and flattening of pyramids
    • the ureters may also be dilated
      • hydroureter
  • clinical course
    • bilateral complete obstruction
      • anuria
      • bladder distension if block is below bladder
    • incomplete obstruction
      • frequrea
      • polyurea
      • dilute urine