What are the differences in management between Acute Kidney Injury (AKI) and Chronic Kidney Disease (CKD)?

Management Differences Between Acute Kidney Injury (AKI) and Chronic Kidney Disease (CKD)

The management of AKI focuses on identifying and treating reversible causes, while CKD management emphasizes slowing progression and managing complications through long-term strategies based on GFR and albuminuria staging. 1

Definitions and Time Frames

• AKI is defined as a rapid increase in serum creatinine (≥0.3 mg/dL within 48 hours or ≥1.5 times baseline within 7 days) or decreased urine output (<0.5 mL/kg/h for 6 hours) 2, 3
• Acute Kidney Disease (AKD) bridges AKI and CKD, representing kidney dysfunction present for 7 days to 3 months 2, 1
• CKD is defined as kidney dysfunction persisting for more than 3 months 2, 1

Diagnostic Approach Differences

• AKI staging is based on relative changes in serum creatinine or urine output 1
• CKD staging uses absolute GFR values and albuminuria categories 1
• When transitioning from AKI to CKD management, the approach shifts from relative changes to absolute GFR values, typically before 90 days 1

Management Priorities for AKI

• Discontinue nephrotoxic agents when possible 1, 4
• Ensure appropriate volume status and perfusion pressure 1, 4
• Monitor serum creatinine and urine output closely 1
• Consider invasive diagnostic workup (kidney biopsy) for unresolving AKI 1
• Adjust medication dosing based on changing kidney function 1, 4
• Consider kidney replacement therapy for severe cases 1
• Identify and treat the underlying cause (sepsis, cardiorenal syndrome, obstruction) 3

Management Priorities for CKD

• Focus on cause-specific classification with GFR and albuminuria staging (CGA classification) 1
• Implement long-term strategies to slow progression 4, 5
• Consider ACEi or ARB therapy for patients with hypertension and proteinuria 4
• Manage anemia with iron supplementation and possibly erythropoiesis-stimulating agents 4
• Monitor for and treat metabolic complications (hyperkalemia, acidosis, mineral bone disorders) 4
• Prepare for renal replacement therapy when approaching end-stage kidney disease 4, 5

Transitional Management (AKD)

• As GFR stabilizes after AKI, transition from AKI-based staging to GFR-based categories 1
• For patients with community-acquired AKI or unknown baseline function, use GFR-based approach once stability is achieved 1
• Consider using measured GFR rather than estimated GFR when kidney function is changing rapidly 1
• In patients with low muscle mass, consider cystatin C for GFR estimation 1
• Monitor for maladaptive repair mechanisms that may accelerate progression to CKD 5, 6

Follow-up Considerations

• AKI survivors require long-term follow-up even if they appear to recover kidney function 5, 7
• Risk of CKD progression increases with AKI severity, duration, and frequency 5, 7
• Approximately 25% of AKI survivors develop AKD 8
• Pre-existing CKD amplifies the risk of poor outcomes after AKI 7, 6
• Implement strategies to prevent recurrent AKI episodes, which can accelerate CKD progression 7, 6

Common Pitfalls to Avoid

• Assuming complete recovery after AKI without follow-up monitoring 5, 7
• Failing to adjust medication dosing during the transition from AKI to CKD 1, 4
• Overlooking the bidirectional relationship between AKI and CKD 5, 7
• Interpreting cardiac biomarkers (BNP/NT-proBNP, troponin) without considering reduced GFR 4
• Using dual RAAS blockade, which increases hyperkalemia and AKI risk 4
• Neglecting to consider the cumulative effect of multiple AKI episodes on CKD progression 7, 6