What is the management plan for a patient with Acute Kidney Injury (AKI)?

Management of Acute Kidney Injury (AKI)

The management of acute kidney injury requires prompt identification of the underlying cause, removal of nephrotoxic agents, optimization of fluid status, and appropriate supportive care to prevent complications and progression to chronic kidney disease. 1

Definition and Diagnosis

• AKI is defined by any of the following: increase in serum creatinine by ≥0.3 mg/dL within 48 hours; increase in serum creatinine to ≥1.5 times baseline within 7 days; or urine output <0.5 mL/kg/h for 6 hours 1
• AKI is staged for severity according to changes in serum creatinine and urine output, with higher stages associated with worse outcomes 1
• Pathophysiology includes intrinsic renal pathology (thrombotic vascular processes, tubular injury, glomerulonephritis) and extrinsic factors (fluid depletion, multi-organ failure, rhabdomyolysis) 1
• Biochemical tests should include serum urea, creatinine, electrolytes (sodium, potassium, bicarbonate) at least every 48 hours or more frequently in high-risk patients 1

Initial Management

1. Identify and Treat Underlying Cause

• Conduct rigorous search for infection (blood cultures, urine cultures, chest radiograph) 1
• Perform diagnostic paracentesis in patients with cirrhosis to evaluate for spontaneous bacterial peritonitis 1
• Start broad-spectrum antibiotics when infection is strongly suspected 1
• Address specific causes such as obstruction, nephrotoxic medications, or intrinsic renal disease 1

2. Medication Review and Adjustment

• Discontinue nephrotoxic medications (NSAIDs, aminoglycosides, etc.) unless essential 1
• Hold diuretics and nonselective beta-blockers when AKI is diagnosed 1
• Consult pharmacy for medication dosing adjustments in renal impairment 1
• Avoid using dopamine, diuretics, N-acetylcysteine, or recombinant human insulin-like growth factor 1 for treatment of AKI 1

3. Fluid Management

• Use isotonic crystalloids rather than colloids for initial management of volume expansion 1, 2
• Target euvolemia (optimal fluid status) through careful assessment of fluid balance 1
• Monitor fluid status by clinical examination and fluid balance daily 1
• Replace fluid losses and administer albumin 1 g/kg/d for 2 days if serum creatinine shows doubling from baseline 1
• Avoid overzealous fluid resuscitation as it may worsen outcomes and lead to tissue edema 2, 3

4. Hemodynamic Support

• Implement goal-directed fluid and vasopressor management with close hemodynamic monitoring 1
• Use vasopressors in conjunction with fluids in patients with vasomotor shock 2
• Monitor urine output, vital signs, and when indicated, use echocardiography or CVP to guide fluid management 1

Management of Specific Complications

1. Hepatorenal Syndrome (HRS-AKI)

• When serum creatinine remains higher than twice baseline despite initial measures, treat with albumin (1 g/kg IV on day 1, then 20-40 g daily) plus vasoactive agents 1
• Options for vasoactive agents include terlipressin, octreotide/midodrine combination, or norepinephrine 1
• Continue therapy until serum creatinine returns to within ≤0.3 mg/dL of baseline for 2 consecutive days or for a maximum of 14 days 1

2. Electrolyte Abnormalities

• Monitor and correct electrolyte imbalances (hyperkalemia, metabolic acidosis, hyponatremia) 1
• Be aware that AKI in specific contexts (e.g., COVID-19) may present with unique electrolyte patterns including both increased and decreased sodium and potassium levels 1

3. Renal Replacement Therapy (RRT)

• Consider RRT for severe complications of AKI (refractory hyperkalemia, acidosis, volume overload, uremic symptoms) 1
• CRRT is preferable in hemodynamically unstable patients and those with acute brain injury 1
• PIRRT (Prolonged Intermittent Renal Replacement Therapy) is a reasonable alternative to CRRT in hemodynamically unstable adult patients 1
• Optimal timing of RRT initiation remains uncertain and requires individualized assessment 1, 4

Prevention of AKI Progression and Follow-up

• Implement protocol-based management of hemodynamic and oxygenation parameters in high-risk patients 2
• Provide adequate nutritional support, preferably via enteral route when possible 2
• Ensure protein intake is not restricted with the aim of preventing or delaying RRT 2
• Monitor patients for development or progression of chronic kidney disease after AKI 1
• Consider follow-up evaluation for patients with risk factors for progression to CKD, particularly those who suffered severe AKI requiring temporary RRT 1

Common Pitfalls and Considerations

• Avoid using the AKI staging system alone for clinical management; consider other factors including trends in renal function, cause of AKI, and comorbid conditions 1
• Be cautious with hyperchloremic solutions (normal saline) as they can induce metabolic acidosis; consider balanced electrolyte solutions when appropriate 2
• Recognize that fluid overload can delay renal recovery and contribute to ongoing organ dysfunction 3, 5
• Avoid rapid or excessive fluid removal with diuretics or extracorporeal therapy as it might lead to hypovolemia and recurrent renal injury 5
• Implement accurate fluid balance monitoring to help prevent AKI, particularly in high-risk settings such as trauma 6