What is the initial management of acute kidney injury?

Initial Management of Acute Kidney Injury

The initial management of acute kidney injury (AKI) should focus on removing potential nephrotoxic agents, optimizing hemodynamics with appropriate fluid resuscitation, and addressing underlying causes. 1

Definition and Recognition

AKI is defined by:

• Increase in serum creatinine by ≥0.3 mg/dL within 48 hours, OR
• Increase in serum creatinine by ≥50% within 7 days, OR
• Urine output <0.5 mL/kg/h for >6 hours 1

Step-by-Step Management Algorithm

1. Immediate Actions

• Discontinue nephrotoxic medications:

  • NSAIDs
  • Aminoglycosides
  • Certain antibiotics
  • ACE inhibitors/ARBs
  • Contrast agents when possible 1

• Optimize hemodynamics:

  • Administer intravenous fluids for hypovolemic patients
  • For patients with cirrhosis: albumin 1g/kg/day (maximum 100g) for 2 days 1
  • Use balanced crystalloid solutions rather than 0.9% saline when possible 1

2. Identify and Treat Underlying Causes

• Treat infections promptly with appropriate antibiotics 1
• Correct hypotension with vasopressors if fluid-resistant
• Relieve urinary obstruction if present (based on ultrasound findings)
• Adjust medication dosages according to reduced kidney function 1

3. Supportive Care

• Monitor fluid status carefully to avoid both hypovolemia and fluid overload
• Adjust diuretic therapy - typically hold diuretics initially unless treating volume overload 1
• Maintain glycemic control 2
• Provide nutritional support appropriate for kidney function 2

Special Considerations

For Patients with Cirrhosis

• Hold beta-blockers and diuretics
• Administer albumin 1g/kg/day for 2 days (maximum 100g/day)
• If AKI persists despite these measures, consider hepatorenal syndrome and initiate vasoconstrictors with albumin 1

For Critically Ill Patients

• Maintain mean arterial pressure >65 mmHg
• Avoid excessive fluid administration once euvolemic
• Consider early renal replacement therapy for severe metabolic derangements 3, 4

Monitoring Response

• Check serum creatinine daily
• Monitor urine output hourly in critically ill patients
• Reassess fluid status frequently
• Adjust medication doses according to kidney function 1, 2

Common Pitfalls to Avoid

• Delayed recognition of AKI - monitor high-risk patients closely
• Continued administration of nephrotoxic drugs
• Excessive fluid administration leading to volume overload
• Inadequate fluid resuscitation in truly hypovolemic patients
• Failure to identify and treat the underlying cause 1, 5

When to Consult Nephrology

• Stage 3 AKI (creatinine >3× baseline)
• Inadequate response to initial management
• Uncertain etiology
• Need for renal replacement therapy
• Pre-existing CKD stage 4 or higher 2

By following this systematic approach to AKI management, focusing on removing nephrotoxic agents, optimizing hemodynamics, and addressing underlying causes, patient outcomes can be significantly improved.