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

Management of Acute Kidney Injury (AKI)

The management of acute kidney injury requires immediate identification of the underlying cause, discontinuation of nephrotoxic medications, optimization of fluid status, and implementation of supportive measures to prevent further kidney damage and reduce mortality. 1

Diagnosis and Classification

• AKI is defined by KDIGO criteria 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
• AKI should be staged according to severity (stages 1-3) to guide management decisions, with stage 3 representing the most severe form 1
• The cause of AKI should be determined whenever possible, with special attention to reversible causes, by classifying it as prerenal, intrinsic renal, or postrenal 2, 3

Initial Management Steps

• Immediately discontinue all nephrotoxic medications including ACE inhibitors, ARBs, NSAIDs, and diuretics 1, 4
• Assess volume status through clinical examination and potentially central venous pressure monitoring to guide fluid management 1
• Implement a comprehensive drug stewardship program that includes identification of patients at risk for AKI and medication review 4
• Adjust dosages of all medications based on reduced GFR 4
• Obtain kidney ultrasound to rule out obstructive uropathy, especially in older men with risk factors for obstruction 1, 5

Fluid Management

• For hypovolemic patients: provide fluid repletion with isotonic crystalloids rather than colloids 1
• For patients with cirrhosis and AKI: administer albumin 1 g/kg/day (maximum 100 g/day) for 2 days if serum creatinine shows doubling from baseline 2
• Avoid aggressive fluid administration in non-hypovolemic patients, which can worsen outcomes 4
• Monitor fluid balance with strict input/output measurements 4

Management of Specific Causes

Hepatorenal Syndrome (HRS-AKI)

• When serum creatinine remains higher than twice the baseline value despite initial measures, treat HRS-AKI with albumin at a dose of 1 g/kg intravenously on day 1 followed by 20–40 g daily 2
• Add vasoactive agents (terlipressin; or if unavailable, either octreotide and midodrine; or norepinephrine) 2
• Continue therapy until 24 hours following the return of serum creatinine to within ≤0.3 mg/dL of baseline for 2 consecutive days or for a total of 14 days 2

Infection-Associated AKI

• Perform rigorous search for infection in all patients with AKI 2
• For patients with cirrhosis, perform diagnostic paracentesis to evaluate for spontaneous bacterial peritonitis 2
• Start broad-spectrum antibiotics whenever infection is strongly suspected 2

Monitoring and Supportive Care

• Monitor serum electrolytes, BUN, and creatinine every 4-6 hours initially 4, 1
• Maintain adequate mean arterial pressure (typically >65 mmHg) to ensure renal perfusion 1
• Correct electrolyte abnormalities, particularly hyperkalemia, which may require urgent intervention 1
• Monitor for signs of uremic complications 4

Indications for Renal Replacement Therapy (RRT)

• Consider RRT for severe oliguria unresponsive to fluid resuscitation, severe metabolic acidosis, refractory hyperkalemia, uremic complications, and fluid overload 4, 1
• Reassess the need for continued RRT daily 1
• Avoid delaying RRT when clear indications exist, as this increases mortality 1

Prevention Strategies

• Identify patients at risk for AKI (older age, diabetes, chronic kidney disease, heart failure, sepsis) 1
• Ensure adequate hydration before procedures involving contrast agents 1
• Avoid the "triple whammy" combination of NSAIDs, diuretics, and ACE inhibitors/ARBs, which more than doubles the risk of AKI 4

Follow-up After AKI

• Schedule close post-discharge clinical evaluation for patients with moderate to severe AKI given the association with long-term outcomes such as renal function decline and mortality 2
• Risk stratification based on AKI severity may be useful in guiding the timing of outpatient follow-up, with earlier follow-up for those with stage 3 AKI 2
• Monitor for development of chronic kidney disease, especially in patients who had AKI in the setting of pre-existing CKD 2, 6

Common Pitfalls to Avoid

• Inappropriate continuation of nephrotoxic medications during AKI recovery phase 4, 1
• Overly aggressive fluid administration in non-hypovolemic patients 4
• Failing to identify and address the underlying cause of AKI 1
• Neglecting to adjust medication dosages as kidney function changes during recovery 4
• Overly rapid correction of hyponatremia, which can lead to osmotic demyelination syndrome 4