What are the steps for managing Acute Kidney Injury (AKI)?

Management of Acute Kidney Injury

Immediately discontinue all nephrotoxic medications (ACE inhibitors, ARBs, NSAIDs, diuretics) and assess volume status to guide fluid management, while simultaneously ruling out urinary obstruction with renal ultrasound. 1, 2

Initial Assessment and Diagnosis

Diagnostic Criteria:

• AKI is defined as serum creatinine increase ≥0.3 mg/dL within 48 hours, ≥50% increase from baseline within 7 days, or urine output <0.5 mL/kg/hour for 6 hours 2, 3
• Stage the severity using KDIGO criteria (Stage 1-3, with Stage 3 being most severe) 3

Immediate Diagnostic Workup:

• Obtain urinalysis to detect hematuria, proteinuria, or abnormal sediment to exclude structural renal diseases 1, 2
• Perform renal ultrasound immediately to rule out obstructive uropathy 1, 2
• Classify AKI as prerenal, intrinsic renal, or postrenal to identify reversible causes 3, 4
• For cirrhosis patients, perform diagnostic paracentesis to evaluate for spontaneous bacterial peritonitis 2, 3

Medication Management

Critical First Step:

• Stop all nephrotoxic agents immediately: ACE inhibitors, ARBs, NSAIDs, and diuretics 1, 2
• Adjust dosages of all remaining medications based on reduced GFR 1, 2
• Avoid the "triple whammy" combination of NSAIDs, diuretics, and ACE inhibitors/ARBs, which more than doubles AKI risk 2
• Implement comprehensive drug stewardship with frequent reassessment as kidney function changes 1, 2

Common Pitfall: Inappropriate continuation of nephrotoxic medications during AKI recovery leads to continued kidney damage 1, 2

Fluid and Hemodynamic Management

Volume Status Assessment:

• Assess through clinical examination and potentially central venous pressure monitoring 2, 3

Fluid Management Algorithm:

• Hypovolemic patients: Provide fluid repletion with isotonic crystalloids (not colloids) 2, 3
• Euvolemic or hypervolemic patients: Implement fluid restriction to prevent volume overload 2
• Avoid hypotonic fluids which worsen hyponatremia 1, 2
• Monitor for signs of fluid overload: peripheral edema, pulmonary congestion, weight gain 2

Hemodynamic Targets:

• Maintain mean arterial pressure >65 mmHg to ensure renal perfusion 3
• Determine optimal vasopressor targets based on clinical context 2, 3

Critical Pitfall: Overly aggressive fluid administration in non-hypovolemic patients worsens outcomes 1, 2

Monitoring and Complications Management

Intensive Monitoring Protocol:

• Monitor serum electrolytes, BUN, and creatinine every 4-6 hours initially 1, 2, 3
• Track fluid balance with strict input/output measurements 1, 2
• Monitor for uremic complications 1, 2

Electrolyte Management:

• Correct hyperkalemia urgently when present 3
• Avoid overly rapid correction of hyponatremia to prevent osmotic demyelination syndrome 1, 2
• Consider sodium bicarbonate for patients with metabolic acidosis 2

Renal Replacement Therapy (RRT)

Urgent Indications for RRT:

• Severe oliguria unresponsive to fluid resuscitation 1, 2, 3
• Severe metabolic derangements or acidosis 2, 3
• Uremic symptoms (encephalopathy, pericarditis, pleuritis) 1, 2
• Refractory fluid overload 1, 2
• Refractory hyperkalemia 5

RRT Management:

• Reassess need for continued RRT daily 1, 2, 3
• Evaluate renal function within 3-7 days after last RRT session 2

Critical Pitfall: Delaying RRT when clear indications exist increases mortality 1, 2, 3

Special Population: Cirrhosis Patients

Specific Management Steps:

• Hold diuretics, beta-blockers, and all nephrotoxic drugs 2, 3
• Perform rigorous infection search including diagnostic paracentesis 2, 3
• Administer albumin 1 g/kg/day (maximum 100 g/day) for 2 days if creatinine doubles from baseline 2, 3
• For hepatorenal syndrome: albumin 1 g/kg IV on day 1, then 20-40 g daily, plus vasoactive agents (terlipressin; or octreotide and midodrine; or norepinephrine) 3

Infection Management

• Perform rigorous search for infection in all AKI patients 3
• Start broad-spectrum antibiotics when infection is strongly suspected 3
• Identify and treat precipitating causes promptly 1

Follow-up and Long-term Management

Post-AKI Monitoring:

• Evaluate renal function within 3-7 days after last RRT session 2
• Schedule follow-up at 3 months after AKI to assess resolution or progression to chronic kidney disease 2
• Consider nephrology referral for severe AKI (Stage 2-3), unclear etiology, or risk factors for CKD progression 2, 6

Patient Education:

• Educate regarding medication avoidance, especially over-the-counter NSAIDs 1, 2
• Teach when to seek medical attention for worsening kidney function symptoms 1

Prevention Strategies

Risk Factor Identification:

• Identify high-risk patients: older age, diabetes, chronic kidney disease, heart failure, sepsis 3
• Ensure adequate hydration before contrast procedures 3
• Implement comprehensive drug stewardship programs 1, 2

Critical Pitfall: Failing to identify and address the underlying cause of AKI leads to continued kidney damage 1, 2, 3