What is the best treatment for acute kidney injury (AKI)?

Best Treatment for Acute Kidney Injury

The best treatment for acute kidney injury (AKI) is to identify and address the underlying cause while implementing supportive measures including discontinuation of nephrotoxic medications, optimization of fluid status, and management of complications. 1, 2

Diagnosis and Classification

AKI is defined by:

• Increase in serum creatinine ≥0.3 mg/dL within 48 hours, or
• Increase in serum creatinine ≥1.5 times baseline within 7 days, or
• Urine output <0.5 mL/kg/h for 6 hours or more 2

AKI is classified into three stages based on severity:

Stage	Serum Creatinine	Urine Output
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 for ≥12h

Treatment Algorithm

Step 1: Identify and Treat the Underlying Cause

• Determine if AKI is prerenal, intrinsic renal, or postrenal through history, physical examination, laboratory tests, and imaging 1
• For postrenal causes (obstruction): Relieve the obstruction promptly
• For prerenal causes: Address volume depletion or hemodynamic instability
• For intrinsic causes: Treat specific conditions (e.g., glomerulonephritis, acute tubular necrosis)

Step 2: Implement Immediate Supportive Measures

1. Review and adjust medications:

   • Discontinue all nephrotoxic drugs (NSAIDs, aminoglycosides, etc.)
   • Avoid "triple whammy" combinations (NSAIDs, diuretics, ACE inhibitors/ARBs) 1, 2
   • Hold diuretics and nonselective beta-blockers 1
   • Adjust medication doses based on current renal function

2. Optimize fluid status:

   • For hypovolemia: Administer isotonic crystalloids (normal saline or balanced solutions) 2
   • For patients with cirrhosis and AKI: Consider albumin 1 g/kg/day (maximum 100 g/day) for 2 consecutive days 1
   • For volume overload: Consider diuretics once euvolemic or hypervolemic state is confirmed

3. Manage electrolyte and acid-base disturbances:

   • Correct hyperkalemia, metabolic acidosis, and other electrolyte abnormalities
   • Monitor serum electrolytes, BUN, creatinine daily 2

Step 3: Specific Interventions Based on Etiology

For Hepatorenal Syndrome (HRS-AKI):

• After volume expansion with albumin (1 g/kg/day for 2 days), if serum creatinine remains >2× baseline:
  • Initiate vasoactive therapy with albumin (20-40 g/day) plus one of:
    • Terlipressin: 1 mg every 4-6 hours, increasing to 2 mg every 4-6 hours if no response
    • Midodrine (7.5-12.5 mg TID) plus octreotide (100-200 μg TID)
    • Norepinephrine (0.5-3 mg/h continuous infusion)
  • Continue until serum creatinine returns to within ≤0.3 mg/dL of baseline for 2 consecutive days or for 14 days 1

For Infection-Associated AKI:

• Prompt initiation of appropriate antibiotics
• Source control of infection
• Hemodynamic support as needed 1

Step 4: Consider Renal Replacement Therapy (RRT)

Indications for RRT include:

• Refractory hyperkalemia
• Severe metabolic acidosis
• Volume overload unresponsive to diuretics
• Uremic symptoms (encephalopathy, pericarditis, pleuritis)
• Certain toxin removals 2

RRT modality selection:

• For hemodynamically unstable patients: Continuous RRT (CRRT)
• For stable patients: Intermittent hemodialysis
• For patients with cirrhosis: Individualize based on hemodynamic status 2

Monitoring and Follow-up

• Daily monitoring of serum creatinine, BUN, electrolytes, fluid balance
• Monitor urine output, vital signs
• For patients with cirrhosis: Consider echocardiography or CVP monitoring 1
• Follow patients who recover from AKI closely (assessment of serum creatinine every 2-4 days during hospitalization and every 2-4 weeks for 6 months after discharge) 1

Prevention Strategies

• Avoid nephrotoxic medications when possible
• Ensure adequate hydration before contrast procedures
• Use the lowest effective dose of potentially nephrotoxic medications
• Avoid large-volume paracentesis without albumin replacement in cirrhotic patients 1

Common Pitfalls to Avoid

• Delayed recognition and treatment of the underlying cause
• Failure to discontinue nephrotoxic medications
• Inappropriate fluid management (either under-resuscitation or volume overload)
• Delayed initiation of RRT when indicated
• Failure to adjust medication doses in AKI 2
• Overlooking the need for nephrology consultation in severe AKI (Stage 3) or when etiology is unclear

By following this structured approach to AKI management with prompt identification and treatment of the underlying cause, implementation of supportive measures, and appropriate use of RRT when indicated, outcomes can be significantly improved.