Acute Kidney Injury
at the bedside
- AKI = creatinine ≥ 1.5× baseline in 7 days, or a rise ≥ 26.5 µmol/L in 48 h, or urine < 0.5 mL/kg/h for 6 h
- stage 1: 1.5–1.9× · stage 2: 2–2.9× · stage 3: ≥ 3×, ≥ 354 µmol/L, or urine < 0.3 mL/kg/h for 24 h; stage 3 → nephrology today
- check vitals, fluid status, urine output, bladder: dry, overloaded, or obstructed?
- stop nephrotoxins now; ECG if K⁺ high
escalate now if
- hyperkalemia → potassium
- pulmonary edema → overloaded
- severe metabolic acidosis → nephrology now
- uremic encephalopathy or pericarditis → dialysis
- anuria with a distended bladder → obstructed
focused check
- dry → vomiting, diarrhea, poor intake, diuretics, bleeding, sepsis
- obstructed → retention, LUTS, flank pain, anuria, single kidney
- intrinsic → hematuria, foamy urine, rash, hemoptysis; drugs: NSAIDs, ACEi / ARB, contrast, aminoglycosides, vancomycin
send now
- RFT, CBC, VBG (K⁺, pH), Ca²⁺, Mg⁺⁺, PO₄; CK if rhabdomyolysis possible
- urinalysis + microscopy; bladder scan
- renal ultrasound if obstruction suspected or no cause found; CT KUB if stones
- contrast needed → balanced crystalloid before and after; no NAC; do not delay urgent imaging for AKI
calculator FENa · MDCalc ↗︎
treat
- treat the cause; stop nephrotoxins, renally dose everything else; strict input / output, daily weight
CrCl calculator
- dry → balanced crystalloid 250–500 mL IV bolus, reassess, repeat until euvolemic, then maintenance
- obstructed → catheter now; not relieved or upper tract → urology (nephrostomy / stent); urine > 200 mL/h for 2 consecutive hours after relief → post-obstructive diuresis: replace cautiously by volume status and electrolytes, not 1:1
- overloaded → loop diuretic by prior exposure: furosemide 40 mg IV if diuretic-naive, or double the daily oral dose given IV; restrict fluids by congestion and intake, not a fixed figure; diuretics treat overload, not AKI, never when dry
- creatinine + K⁺ daily, twice daily in stage 2–3 or after any correction
- nephrology now → refractory K⁺ or acidosis (pH < 7.1), overload not responding to diuretics, uremic encephalopathy or pericarditis, dialyzable poison, suspected GN / vasculitis
- urology now → infected obstructed system, bilateral or single-kidney obstruction, catheter fails
- hand over → creatinine and urine-output trend, dialysis triggers, who to call
evidence
| source | type |
|---|---|
| KDIGO AKI staging criteria | international guideline |
| PRESERVE trial 2017, ACT trial 2011 (contrast-AKI, N-acetylcysteine) | major peer-reviewed trials |
| ACR Manual on Contrast Media, 2024 edition (current NAC/hydration guidance) | specialty-society guidance |
Verify indication, dose, allergies, interactions, renal/hepatic function and local protocols before prescribing.
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reviewed Jul 2026updated Oct 2026file lab/rft-acute-kidney-injury