AKI

• related: Nephrology
• tags: #note

• AKI is either oliguric or nonoliguric
• prerenal AKI: responds to fluids
• ATN = AKI + one of following
  • not responding to fluids
  • labs: UNa, FENA, casts
• Contrast AKI happens more often with 2 hits, contrast + one of following
  • nsaids
  • ckd
  • ace/arb
  • diabetes
• CKD-epi calculator is better than Cr or GFR alone

Prerenal azotemia is associated with decreased fractional excretion of sodium; however, once ATN sets in, the fractional excretion of sodium increases (usually >2). Response to a fluid challenge is the gold standard in distinguishing prerenal azotemia (which responds to a fluid challenge with improved urine output) from ATN. This patient's low urine output and elevated creatinine despite receiving continuous intravenous hydration and showing no signs of hypovolemia (normotension, no tachycardia) suggest ATN.