What are the management strategies for Acute Kidney Injury (AKI)?

Management Strategies for Acute Kidney Injury (AKI)

The management of AKI should focus on identifying and treating the underlying cause, discontinuing nephrotoxic medications, optimizing fluid status, and providing appropriate supportive care based on AKI stage and severity. 1

Definition and Diagnosis

• AKI is defined as:

  • Increase in serum creatinine ≥0.3 mg/dL within 48 hours, OR
  • Increase in serum creatinine ≥50% from baseline within 7 days, OR
  • Urine output <0.5 mL/kg/h for >6 hours

• AKI is staged according to severity:

  Stage	Creatinine Criterion	Urine Output Criterion
  1	Increase ≥0.3 mg/dL or 1.5-1.9× baseline	<0.5 mL/kg/h for 6-12h
  2	2.0-2.9× baseline	<0.5 mL/kg/h for ≥12h
  3	≥3.0× baseline or ≥4.0 mg/dL or RRT initiation	<0.3 mL/kg/h for ≥24h or anuria ≥12h

Initial Management Steps

1. Identify and treat the underlying cause 2, 1

   • Determine if AKI is prerenal, intrinsic renal, or postrenal
   • Address specific etiologies (infection, obstruction, hypovolemia)

2. Medication management 2, 1

   • Discontinue nephrotoxic medications (NSAIDs, aminoglycosides, contrast agents)
   • Temporarily hold diuretics and beta-blockers in appropriate cases
   • Adjust medication dosages based on kidney function

3. Volume management 2, 1

   • Use isotonic crystalloids rather than colloids for initial volume expansion
   • Administer 500-1000 mL initial bolus for hypovolemic patients, then reassess
   • For patients with cirrhosis and ascites, use albumin 1 g/kg/day (maximum 100g) for two consecutive days

4. Hemodynamic support 2

   • Use vasopressors in conjunction with fluids in patients with vasomotor shock
   • Consider protocol-based management of hemodynamic parameters in high-risk perioperative patients or those with septic shock

Nutritional Support

• Provide 20-30 kcal/kg/day total energy intake 2, 1
• Do not restrict protein intake to delay RRT initiation 2
• Administer protein based on clinical status 2:
  • 0.8-1.0 g/kg/day in non-catabolic AKI patients without dialysis
  • 1.0-1.5 g/kg/day for patients on RRT
  • Up to 1.7 g/kg/day for patients on continuous RRT and hypercatabolic patients
• Provide nutrition preferentially via the enteral route 2

Specific Interventions to Avoid

• Do not use diuretics to prevent AKI 2
• Do not use diuretics to treat AKI, except for managing volume overload 2
• Do not use low-dose dopamine to prevent or treat AKI 2
• Do not use fenoldopam to prevent or treat AKI 2
• Do not use atrial natriuretic peptide to prevent or treat AKI 2
• Do not use recombinant human IGF-1 to prevent or treat AKI 2

Renal Replacement Therapy (RRT)

Consider RRT when any of the following are present 1:

• Severe metabolic acidosis (pH < 7.15)
• Hyperkalemia (K > 6.5 mEq/L) refractory to medical management
• Volume overload unresponsive to diuretics
• Uremic symptoms (encephalopathy, pericarditis)
• BUN > 100 mg/dL

Special Considerations

Cirrhosis-Associated AKI

• Discontinue diuretics and beta-blockers 1
• Administer albumin 1 g/kg/day for two consecutive days (maximum 100g/day) 2, 1
• Consider vasoconstrictors (terlipressin first-line) with albumin for hepatorenal syndrome 1

Medication Dosing

• Monitor aminoglycoside drug levels when treatment with multiple daily dosing is used for more than 24 hours 2
• If aminoglycosides must be used, administer as a single daily dose rather than multiple-dose regimens in patients with normal kidney function 2

Monitoring and Follow-up

• Monitor daily serum creatinine, BUN, electrolytes, and urinalysis 1
• Target blood glucose of 110-149 mg/dL (6.1-8.3 mmol/L) 2, 1
• Schedule follow-up within 3 months to assess for development of CKD 1
• Consider earlier and more frequent monitoring for high-risk patients (severe AKI, pre-existing CKD) 1

Prevention of Complications

• Provide thromboprophylaxis with UFH or LMWH unless contraindicated 1
• If creatinine clearance is < 30 mL/min, use dalteparin or UFH 1
• Monitor for and treat electrolyte abnormalities, particularly hyperkalemia

Common Pitfalls to Avoid

• Inappropriate fluid administration leading to volume overload
• Failure to identify and address the underlying cause of AKI
• Continued use of nephrotoxic medications
• Delayed recognition of indications for RRT
• Inadequate follow-up after AKI episode, missing progression to CKD

The KDIGO guidelines emphasize that AKI management should be tailored to the stage and cause, though this approach has been criticized for assuming homogeneity within AKI stages and may not be clinically helpful in all cases 2. A systematic approach focusing on treating the underlying cause while providing appropriate supportive care remains the cornerstone of effective AKI management.