Acute Renal Failure

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Acute Renal Failure

• Anil Menon
• 11/27/06

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A simple algorithm

• Malingering
• Rapid fall in GFR leading to increased waste
  products

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Relevance

• Complicates up to 7 of admissions
• Mortality when dialysis is required ranges 50-75

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DDX

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Diagnostic Approach

• Cr/BUN, UOP, serum cystatin K, IL18
• HP
• Meds
• Labs
• Imaging

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Acute or Chronic?

• History
• Previous creatinine
• Small kidneys on u/s

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Obstruction excluded?

• History
• Complete anuria
• Palpable bladder
• Renal u/s

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Euvolemic?

• Pulse, JVP/CVP, orthostatic, wgt, I/O
• Disproportionate inc in ureaCr ratio
• FENA
• Fluid challenge

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Evidence of parenchymal dz? Other than ATN

• HP (systemic factors)
• Urine dipstick and micro
• (red cells, red cell casts, eosinophils, prot)

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Major vascular occlusion?

• Athreosclerosis
• Renal Assymetry
• Groin pain
• Complete Anuria
• Macro Hematuria

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Treatment

• Prevention
• Risk factors (age,DM,HTN,Vasc,renal)
• Maintain BP and Volume, avoid neprhotox
• Measure plasma aminoglycoside
• Allopurinol/urine alk in cancer

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General

• Correct prerenal/postrenal factors
• Optimise CO, RBF
• Review meds
• Monitor I/O
• Nutritional support
• Treat infection, bleeding
• Start dialysis before uremic

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No strong evidence

• Loop diuretic
• Dopamine
• Natriuretic peptide
• Intermittent HD vs Continuous
• ILF
• Thyroxine

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ATN

• Sepsis in ICU 35-50
• Prerenal azotemia spectrum with ischemic ATN
• Initiation, maintenance, recovery
• BUN/Cr normal 101
• Rapid rise plasma Cr
• Muddy brown epi casts
• FENa gt 2
• Ucr / PCr

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Post Op

• 18-40 hospital aquired. 1.2 surgery.
• Pre-op BP control (Carmaichael J Surgery 2003)
• Hydration and prevention
• Poor prognosis of ARF when adjusted (Svensson J
  Vasc Surg 1989)
• Nephrology

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Contrast

• Isotonic crystalloid 1-1.5ml/kg for 3-12 hours
  pre proc and 6-24 hours post
• Mucomyst not consistently useful
• Current eval of theophyline, statins, vit c, pg E
• CCB, L-arg, fenoldopam, dopamine, ANP not useful
• Prophylactic HD no gain
• (Stacul 2006 CIN consensus working panel)

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