Management of Acute Kidney Injury (AKI)

Diagnosis and Classification

The American College of Cardiology defines AKI as an increase in serum creatinine ≥0.3 mg/dL within 48 hours, an increase ≥50% from baseline within 7 days, or a decrease in urine output to <0.5 mL/kg/hour for 6 hours 1

Obtain urinalysis to detect hematuria, proteinuria, or abnormal urinary sediment to exclude structural renal diseases 2
Immediately discontinue all nephrotoxic medications including ACE inhibitors, ARBs, NSAIDs, and diuretics 1, 2
Adjust dosages of all medications based on reduced GFR 1
Perform kidney ultrasound to rule out obstructive uropathy 1

Assess volume status through clinical examination and potentially central venous pressure monitoring 1
For hypovolemic patients: provide fluid repletion with isotonic crystalloids rather than colloids 1, 3
For euvolemic or hypervolemic patients: implement fluid restriction to prevent volume overload 1, 3
Monitor for signs of fluid overload including peripheral edema, pulmonary congestion, and weight gain 1
Avoid hypotonic fluids which can worsen hyponatremia 1

Determine optimal vasopressor targets to improve kidney outcomes in acute medical illness and perioperative settings 4

Monitor serum electrolytes, BUN, and creatinine every 4-6 hours initially 1
Track fluid balance with strict input/output measurements 1
Monitor for signs of uremic complications 1
Avoid overly rapid correction of hyponatremia, which can lead to osmotic demyelination syndrome 1
Explore the role for sodium bicarbonate in patients with AKI and metabolic acidosis 4

Consider RRT for severe AKI (stage 3) or when complications are present such as refractory volume overload, severe electrolyte abnormalities, or metabolic acidosis 3
Indications for urgent RRT include severe oliguria unresponsive to fluid resuscitation, severe metabolic derangements, uremic symptoms, and fluid overload 1
Investigate the optimal timing, dose, and modality of RRT and identify indicators that predict successful discontinuation 4
Reassess the need for continued RRT daily 1

Evaluate renal function within 3-7 days after the last RRT session 3
Perform follow-up at 3 months after AKI to assess resolution or progression to chronic kidney disease 3
Consider nephrology referral for patients with severe AKI or risk factors for progression to chronic kidney disease 3

For cirrhosis patients with AKI, perform rigorous search for infection including diagnostic paracentesis to evaluate for spontaneous bacterial peritonitis 5
In cirrhosis patients, hold diuretics, beta-blockers, and nephrotoxic drugs and discontinue NSAIDs 5, 6
For cirrhosis patients with AKI, administer albumin 1 g/kg/day (maximum 100 g/day) for 2 days if serum creatinine shows doubling from baseline 5

Implement a comprehensive drug stewardship program that includes identification of patients at risk for AKI 1
Avoid the "triple whammy" combination of NSAIDs, diuretics, and ACE inhibitors/ARBs 1
Provide patient education regarding medication avoidance, especially over-the-counter NSAIDs 1