What is the management approach for Acute Kidney Injury (AKI) in pediatric patients?

Management of Acute Kidney Injury (AKI) in Pediatric Patients

The management of pediatric AKI requires prompt identification of the underlying cause, immediate discontinuation of nephrotoxic medications, optimization of fluid status, and early consideration of renal replacement therapy when indicated to prevent progression and reduce mortality. 1

Definition and Diagnosis

Classification

• Use pediatric-modified RIFLE (pRIFLE) criteria or KDIGO criteria for diagnosis and staging:
  • Stage 1: Increase in serum creatinine ≥0.3 mg/dL or 1.5-1.9 times baseline
  • Stage 2: Increase in serum creatinine 2.0-2.9 times baseline
  • Stage 3: Increase in serum creatinine ≥3 times baseline or to ≥4 mg/dL with acute increase of ≥0.5 mg/dL 2

Initial Assessment

• Essential diagnostic tests:
  • Serum creatinine and electrolytes
  • Urinalysis
  • Urine output monitoring (goal >0.5-1 mL/kg/hr)
  • Renal ultrasonography to rule out obstruction 1

Etiologic Classification and Management

1. Prerenal AKI

• Caused by decreased renal perfusion (dehydration, shock, heart failure)
• Management:
  • Administer isotonic crystalloids for hypovolemia
  • Target mean arterial pressure appropriate for age
  • Consider vasopressors for persistent hypotension 2, 1

2. Intrinsic Renal AKI

• Caused by direct damage to kidney tissue (acute tubular necrosis, glomerulonephritis, HUS)
• Management:
  • Identify and treat specific cause
  • Discontinue nephrotoxic medications
  • Provide supportive care 3

3. Postrenal AKI

• Caused by urinary tract obstruction
• Management:
  • Prompt urologic consultation
  • Relieve obstruction via catheterization or surgical intervention 3

Key Management Principles

Fluid Management

• Optimize volume status:
  • Correct hypovolemia with isotonic crystalloids
  • Avoid fluid overload (associated with worse outcomes)
  • Consider diuretics only after euvolemia is achieved 4, 5
• Monitor fluid balance meticulously with accurate intake/output records 1

Medication Management

• Immediately discontinue nephrotoxic medications:
  • NSAIDs
  • Aminoglycosides
  • ACE inhibitors/ARBs
  • Contrast agents 1
• Adjust medication dosages according to renal function 1

Electrolyte and Acid-Base Management

• Monitor and correct:
  • Hyperkalemia
  • Metabolic acidosis
  • Hypocalcemia
  • Hyperphosphatemia 3

Nutritional Support

• Provide adequate calories (often 120-150% of basal requirements)
• Consider protein restriction only in severe cases awaiting dialysis
• Consult nutrition specialists for individualized plans 3

Renal Replacement Therapy (RRT)

Indications for RRT

• Refractory hyperkalemia (>6.5 mEq/L)
• Severe metabolic acidosis (pH <7.2)
• Volume overload unresponsive to diuretics
• Uremic complications (encephalopathy, pericarditis)
• Severe electrolyte abnormalities 1, 4

RRT Modality Selection

• Peritoneal dialysis (PD):
  • Often preferred in younger/smaller children
  • Requires less technical expertise
  • Provides gradual fluid removal
• Continuous renal replacement therapy (CRRT):
  • Better for hemodynamically unstable patients
  • Allows precise fluid management
• Intermittent hemodialysis (HD):
  • More efficient for rapid toxin removal
  • Requires vascular access and specialized equipment 3, 4

Monitoring and Follow-up

Inpatient Monitoring

• Monitor renal function, electrolytes, and urine output closely
• Follow up with assessments every 2-4 days during hospitalization 1

Long-term Follow-up

• Evaluate renal function at 3 months post-AKI
• Continue monitoring for at least 1-2 years after AKI episode
• Pediatric patients require particularly close follow-up due to higher risk of developing chronic kidney disease (CKD) 2, 6

Prevention Strategies

• Identify high-risk patients (sepsis, cardiac surgery, oncology)
• Ensure adequate hydration before procedures with contrast
• Use nephrotoxic medications judiciously with appropriate monitoring
• Implement early detection protocols using biomarkers when available 7

Common Pitfalls to Avoid

• Delaying treatment of underlying cause
• Excessive fluid administration leading to overload
• Relying solely on urine output as a marker of renal function
• Failure to adjust medication dosages
• Delayed nephrology consultation 1

Special Considerations for Neonates

• Serum creatinine initially reflects maternal levels
• Many neonates have not attained full renal mass development
• AKI in neonates may present with high urine output
• Require specialized fluid and electrolyte management 2

Early identification, prompt treatment of underlying causes, and appropriate supportive care are essential for improving outcomes in pediatric AKI. Close follow-up is critical as pediatric AKI survivors have increased risk of developing CKD later in life 6.