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

Management Strategies for Acute Kidney Injury (AKI)

The management of acute kidney injury requires a systematic approach focused on early identification, addressing underlying causes, optimizing fluid status, discontinuing nephrotoxic medications, and providing appropriate supportive care including renal replacement therapy when indicated. 1, 2

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 3, 2
• AKI should be staged according to severity using KDIGO criteria, with stage 3 being the most severe 3
• Urinalysis, kidney ultrasound, and assessment of fractional excretion of sodium help differentiate between prerenal, intrinsic renal, and postrenal causes 2, 4

Initial Management

• Immediately discontinue all nephrotoxic medications including ACE inhibitors, ARBs, NSAIDs, and diuretics 1, 2
• Implement a comprehensive drug stewardship program that includes identification of patients at risk for AKI and medication review 3, 1
• Avoid the "triple whammy" combination of NSAIDs, diuretics, and ACE inhibitors/ARBs which significantly increases AKI risk 2
• Adjust dosages of all medications based on reduced GFR and reassess frequently as kidney function changes 1, 2

Fluid Management

• Assess volume status through clinical examination and potentially central venous pressure monitoring 1, 2
• For hypovolemic patients: provide fluid repletion with isotonic crystalloids rather than colloids 2, 5
• For euvolemic or hypervolemic patients: implement fluid restriction to prevent volume overload 2, 5
• Monitor for signs of fluid overload including peripheral edema, pulmonary congestion, and weight gain 1, 2
• Track fluid balance with strict input/output measurements 1, 2

Hemodynamic Support

• Determine optimal vasopressor targets to improve kidney outcomes in acute medical illness 3, 2
• Maintain adequate mean arterial pressure to ensure renal perfusion, typically aiming for >65 mmHg 1, 6
• Consider norepinephrine as the first-line vasopressor for patients with AKI and shock 3, 6

Management of Complications

• Monitor serum electrolytes, BUN, and creatinine every 4-6 hours initially 1, 2
• Correct electrolyte abnormalities, particularly hyperkalemia, which may require urgent intervention 1, 4
• Consider sodium bicarbonate in patients with AKI and severe metabolic acidosis 3, 2
• Avoid overly rapid correction of hyponatremia, which can lead to osmotic demyelination syndrome 1, 2

Renal Replacement Therapy (RRT)

• Indications for urgent RRT include:
  • Severe oliguria unresponsive to fluid resuscitation
  • Refractory hyperkalemia
  • Severe metabolic acidosis
  • Uremic complications (encephalopathy, pericarditis)
  • Fluid overload unresponsive to diuretics 1, 2, 4
• Reassess the need for continued RRT daily 1, 2
• For patients with cirrhosis and AKI who are not candidates for liver transplantation, RRT should not be used 3

Special Considerations for Cirrhosis Patients

• Perform rigorous search for infection including diagnostic paracentesis to evaluate for spontaneous bacterial peritonitis 3
• Hold diuretics, beta-blockers, and nephrotoxic drugs 3
• Administer albumin 1 g/kg/day (maximum 100 g/day) for 2 days if serum creatinine shows doubling from baseline 3
• For hepatorenal syndrome with AKI, initiate albumin with vasoactive agents (terlipressin, norepinephrine, or midodrine plus octreotide) 3

Prevention Strategies

• Identify patients at risk for AKI (older age, diabetes, chronic kidney disease, heart failure, sepsis) 1, 2, 4
• Ensure adequate hydration before procedures involving contrast agents 1, 2
• Avoid excessive or unmonitored diuretics 3
• Provide patient education regarding medication avoidance, especially over-the-counter NSAIDs 1, 2

Follow-up and Monitoring

• Evaluate renal function within 3-7 days after AKI resolution or after the last RRT session 2, 7
• Perform follow-up at 3 months after AKI to assess resolution or progression to chronic kidney disease 2, 7
• Consider nephrology referral for patients with severe AKI or risk factors for progression to chronic kidney disease 2, 4

Common Pitfalls to Avoid

• Delaying RRT when clear indications exist, which increases mortality 1, 2
• Failing to identify and address the underlying cause of AKI 1, 2, 4
• Inappropriate continuation of nephrotoxic medications during AKI recovery 1, 2
• Overly aggressive fluid administration in non-hypovolemic patients 1, 5
• Neglecting to adjust medication dosages as kidney function changes 1, 2