What are the steps for managing Acute Kidney Injury (AKI)?

Management of Acute Kidney Injury (AKI)

The management of acute kidney injury requires immediate identification of underlying causes, discontinuation of nephrotoxic agents, optimization of volume status, and timely initiation of renal replacement therapy when indicated. 1

Diagnosis and Classification

• AKI is defined 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, 2
• AKI severity is classified into stages 1-3 based on the degree of creatinine elevation or reduction in urine output 2

Initial Assessment and Management

• Perform a thorough evaluation to categorize AKI as prerenal, intrinsic renal, or postrenal through history, physical examination, laboratory tests, and imaging 3, 4
• Obtain urinalysis to detect hematuria, proteinuria, or abnormal urinary sediment to exclude structural renal diseases 5
• Immediately discontinue all nephrotoxic medications including ACE inhibitors, ARBs, NSAIDs, and diuretics 1, 5
• Adjust dosages of all medications based on reduced GFR 1
• Perform kidney ultrasound to rule out obstructive uropathy 1

Fluid Management

• 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, 6
• For euvolemic or hypervolemic patients: implement fluid restriction to prevent volume overload 1, 6
• Monitor for signs of fluid overload including peripheral edema, pulmonary congestion, and weight gain 1
• Avoid hypotonic fluids which can worsen hyponatremia 1

Hemodynamic Support

• Consider vasopressors to maintain adequate renal perfusion pressure when necessary 6, 7
• Determine optimal vasopressor targets to improve kidney outcomes in acute medical illness and perioperative settings 5

Management of Complications

• 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 5

Renal Replacement Therapy (RRT)

• Consider RRT for severe AKI (stage 3) or when complications are present such as refractory volume overload, severe electrolyte abnormalities, or metabolic acidosis 6, 8
• 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 5
• Reassess the need for continued RRT daily 1

Follow-up and Monitoring

• Evaluate renal function within 3-7 days after the last RRT session 6
• Perform follow-up at 3 months after AKI to assess resolution or progression to chronic kidney disease 6
• Consider nephrology referral for patients with severe AKI or risk factors for progression to chronic kidney disease 6

Special Considerations for Cirrhosis Patients

• 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
• 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

Prevention Strategies

• 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

Common Pitfalls to Avoid

• Delaying RRT when clear indications exist, which increases mortality 1
• Failing to identify and address the underlying cause of AKI 1
• Inappropriate continuation of nephrotoxic medications during AKI recovery 1
• Overly aggressive fluid administration in non-hypovolemic patients 1
• Neglecting to adjust medication dosages as kidney function changes 1