Workup-acute kidney injury (AKI)

• H&P:

  • meds, contrast, or other nephrotoxins;
  • ↓ PO intake, HoTN, infxn/sepsis;
  • trauma, myalgias;
  • BPH/retention.
  • Search for insult 24-48 hr prior ↑ Cr. VS, vol status, rash.

• Urine evaluation:

  • output,
  • urinalysis,
  • urine sediment in AKI,
  • electrolytes,
  • and osmolality

• Fractional excretion Na (FENa) = (UNa/PNa)/(UCr/PCr); if diuretic, ✓ FEUN=(UUN/PUN)/(UCr/PCr)

• Renal U/S or CT: r/o obstruction & cortical atrophy in chronic kidney disease

• Serologies (if indicated): Glomerular Diseases

• Renal biopsy (microscopy, IF, and EM): if etiology unclear (esp. if proteinuria/hematuria). Relative contraindic.: SBP>150, ASA/NSAID, anticoag, cirrhosis. DDAVP if GFR <45.