Renal Failure

Basics

Description

  • Decrease in function of the kidneys that can lead to accumulation of waste products
  • Disorder that can be acute, chronic, or acute-on-chronic
  • Defined by the changes in glomerular filtration rate (GFR) and urine output via RIFLE criteria:
    • RIFLE
      • Risk: Serum Cr increase of 1.5×, or urine output is 0.5 mL/kg/hr for 6 hr
      • Injury: Serum Cr increase of 2–3×, or GFR decrease of 50–75%, or urine output is 0.5 mL/kg/hr for 12 hr
      • Failure: Serum Cr increase >3×, or Cr >4 mg/dL and acute increase of >0.5 mg/dL, or GFR decrease of >75%, or urine output is 0.3 mL/kg/hr for 24 hr, or anuria for 12 hr
      • Loss: Complete loss of kidney function for >4 wk
      • ESRD: Need for renal replacement therapy for >3 mo
  • Staging is relative to patient’s baseline serum Cr and GFR and may not be available to the practitioner
  • Staging is determined by the worst marker

Epidemiology

Incidence And Prevalence Estimates

  • 1 in 7 Americans suffer from CKD
  • Slightly more common in men (14% vs 12%)
  • Elderly (>65 yr old) account for 38% of cases
  • Incidence by ethnicities:
    • Hispanics: 14%
    • Non-Hispanic Black: 16%
    • Non-Hispanic White: 13%
    • Asian: 14%
  • Mortality in those with CKD and >65 is twice as high as their counterparts without CKD at the same age

Etiology

  • Prerenal AKI:
    • Any cause of renal hypoperfusion (septic shock, hypovolemia, hemorrhage, etc.)
  • Intrarenal AKI:
    • Caused by diseases of the renal parenchyma including renal ischemia
  • Postrenal AKI:
    • Caused by physical obstruction of urinary tract (prostatic hyperplasia, prostatitis, gynecologic tumor)
  • Iatrogenic AKI:
    • NSAID, ACE, ARB, aminoglycoside use

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