What is the stepwise management of Acute Kidney Injury (AKI)?

Stepwise Management of Acute Kidney Injury (AKI)

The management of AKI should follow a systematic approach based on identifying the cause, implementing appropriate interventions according to severity, and monitoring for complications, with special attention to discontinuing nephrotoxic agents and ensuring adequate volume status at all stages. 1, 2

Step 1: Initial Assessment and Diagnosis

• Determine the cause of AKI through careful history, physical examination, laboratory tests, and imaging, with special attention to reversible causes 1
• Classify AKI as prerenal (volume responsive), intrinsic renal (including acute tubular necrosis), or postrenal (obstructive) 1, 3
• Perform urinalysis, urine microscopy, and urine chemistry to help differentiate between causes 1, 4
• Obtain kidney ultrasound to rule out obstructive uropathy, especially in older patients 2, 3
• Conduct a rigorous search for infection in all patients with AKI, including blood cultures, urine cultures, and diagnostic paracentesis when appropriate 1

Step 2: Immediate Interventions (For All AKI Stages)

• Discontinue all nephrotoxic medications (NSAIDs, aminoglycosides, contrast agents) 1, 2
• Hold ACE inhibitors, ARBs, diuretics, and adjust beta-blockers as needed 1, 5
• Adjust dosages of all medications based on current estimated GFR 2, 3
• Ensure adequate volume status and perfusion pressure through careful assessment 1, 2
• Replace fluid losses with appropriate fluids, avoiding hypotonic solutions in hyponatremia 2, 5
• Monitor fluid balance with strict input/output measurements 2, 6

Step 3: Management Based on AKI Stage and Cause

Stage 1 AKI:

• Continue interventions from Step 2 1
• Monitor serum creatinine and urine output closely 1, 4
• Treat the underlying cause (e.g., antibiotics for infection, relief of obstruction) 1, 3

Stage 2 AKI:

• Intensify monitoring of renal function and electrolytes 1, 2
• Check for changes in drug dosing requirements 1
• Consider ICU admission based on clinical context, not solely on AKI stage 1
• Begin planning for potential renal replacement therapy (RRT) if progressive deterioration 1, 6

Stage 3 AKI:

• Implement more intensive monitoring of renal function, electrolytes, and acid-base status 1, 2
• Consider RRT for refractory hyperkalemia, severe metabolic acidosis, volume overload unresponsive to diuretics, uremic symptoms, or certain toxin ingestions 2, 3

Step 4: Specific Interventions Based on Cause

For Hypovolemic/Prerenal AKI:

• Administer isotonic fluids cautiously with close monitoring 2, 4
• In cirrhosis with AKI, consider albumin 1 g/kg/d for 2 days if serum creatinine shows doubling from baseline 1

For Hepatorenal Syndrome AKI (HRS-AKI):

• Administer albumin (1 g/kg on day 1, then 20-40 g daily) with vasoactive agents (terlipressin, octreotide/midodrine, 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

For Obstructive AKI:

• Urgent urological consultation for relief of obstruction 3

Step 5: Monitoring and Preventing Complications

• Monitor serum electrolytes, BUN, creatinine every 4-6 hours initially 2
• Watch for signs of fluid overload (peripheral edema, pulmonary congestion) 2, 6
• Avoid overly rapid correction of hyponatremia to prevent osmotic demyelination syndrome 2
• Reassess need for continued RRT daily 2

Step 6: Follow-up After AKI

• Evaluate patients with moderate to severe AKI (stages 2-3) at 3 months post-discharge for resolution, new onset, or worsening of pre-existing CKD 1
• Risk stratification based on AKI severity should guide timing of outpatient follow-up 1, 5
• Provide patient education regarding medication avoidance, especially over-the-counter NSAIDs 2

Common Pitfalls to Avoid

• Delaying identification and treatment of the underlying cause of AKI 2, 4
• Inappropriate continuation of nephrotoxic medications during AKI recovery 2, 3
• Overly aggressive fluid administration in non-hypovolemic patients 2, 6
• Neglecting to adjust medication dosages as kidney function changes 2, 3
• Delaying RRT when clear indications exist 2, 3
• Failing to provide appropriate follow-up for patients with AKI, especially those with severe AKI 1, 7