Management of Acute Kidney Injury
Immediate Actions: Stop Nephrotoxic Medications First
Immediately discontinue all nephrotoxic medications including ACE inhibitors, ARBs, NSAIDs, diuretics, and aminoglycosides as the first priority in AKI management. 1, 2 This single intervention prevents further kidney damage and is the most critical initial step, particularly avoiding the "triple whammy" combination of NSAIDs, diuretics, and ACE inhibitors/ARBs which more than doubles AKI risk. 2
Diagnosis and Staging
Define the Injury Using KDIGO Criteria
- AKI is diagnosed when serum creatinine increases ≥0.3 mg/dL within 48 hours, increases ≥50% from baseline within 7 days, or urine output decreases to <0.5 mL/kg/hour for 6 hours. 1, 3
- Stage the severity immediately: Stage 1 (1.5-1.9× baseline creatinine), Stage 2 (2.0-2.9× baseline), Stage 3 (≥3× baseline or creatinine ≥4.0 mg/dL or initiation of RRT). 1, 3
Determine the Underlying Cause
- Classify as prerenal (inadequate renal perfusion—most common in hospitalized patients), intrinsic renal (acute tubular necrosis from ischemia or nephrotoxins), or postrenal (obstruction). 1, 3, 4
- Obtain urinalysis with microscopy and check urine sodium and fractional excretion of sodium to differentiate prerenal from intrinsic causes. 3, 5
- Perform renal ultrasound immediately to rule out obstruction, especially in older males with prostatic symptoms. 2, 3
Volume Status Assessment and Fluid Management
Assess Volume Status Clinically
- Evaluate through clinical examination for signs of hypovolemia (dry mucous membranes, decreased skin turgor, orthostatic hypotension) versus volume overload (peripheral edema, pulmonary congestion, jugular venous distension). 1, 2
- Consider central venous pressure monitoring in unclear cases. 1, 2
Fluid Resuscitation Strategy
- For hypovolemic patients: provide fluid repletion with isotonic crystalloids rather than colloids. 1, 6
- Avoid hypotonic fluids which worsen hyponatremia. 2
- For volume-overloaded patients: implement fluid restriction and consider diuretics. 2
- Avoid overly aggressive fluid administration in non-hypovolemic patients as this worsens outcomes. 2
Hemodynamic Support
- Maintain mean arterial pressure >65 mmHg to ensure adequate renal perfusion using vasopressors when needed. 1
- Target higher blood pressure goals in AKI compared to other conditions. 7
Stage-Specific Monitoring and Management
Stage 1 AKI
- Monitor serum creatinine and electrolytes daily. 3
- Continue nephrotoxic medication discontinuation and volume optimization. 3
- Reassess medication dosing requirements based on reduced GFR. 3
Stage 2 AKI
- Intensify monitoring to every 4-6 hours for creatinine, BUN, and electrolytes. 3
- Increase frequency of clinical assessments for fluid overload. 3
- Prepare for potential need for renal replacement therapy. 3
Stage 3 AKI
- Monitor electrolytes, BUN, and creatinine every 4-6 hours initially. 1, 2, 3
- Track fluid balance with strict input/output measurements. 2
- Monitor for signs of uremic complications. 2
Renal Replacement Therapy Indications
Urgent RRT is indicated for: severe oliguria unresponsive to fluid resuscitation, refractory hyperkalemia, severe metabolic acidosis (pH <7.1), volume overload causing pulmonary edema, and uremic complications (encephalopathy, pericarditis, pleuritis). 1, 2, 3, 8
- Reassess the need for continued RRT daily. 1, 2
- Early initiation of dialysis has not consistently demonstrated benefit over waiting for clear indications. 7
Medication Management Throughout Recovery
- Implement a comprehensive drug stewardship program that includes identification of at-risk patients and dynamic prescription adjustments based on changing renal function. 1, 2
- Adjust medication dosages based on current estimated GFR and reassess frequently as kidney function changes. 2, 3
- Continue to avoid nephrotoxic medications during the recovery phase. 2
Special Population: AKI in Cirrhosis
Infection Screening
- Perform diagnostic paracentesis in all cirrhotic patients with AKI to evaluate for spontaneous bacterial peritonitis. 1, 3
- Start broad-spectrum antibiotics when infection is strongly suspected. 1
Albumin Administration
- Administer albumin 1 g/kg/day (maximum 100 g/day) for 2 days if serum creatinine shows doubling from baseline. 1, 3
Hepatorenal Syndrome Treatment
- Treat HRS-AKI with albumin 1 g/kg IV on day 1 followed by 20-40 g daily, plus vasoactive agents (terlipressin; or if unavailable, octreotide and midodrine; or norepinephrine). 1, 3
- Hold diuretics and nonselective beta-blockers. 3
Prevention in High-Risk Patients
Identify At-Risk Patients
- Advanced age, pre-existing chronic kidney disease, diabetes mellitus, heart failure, sepsis or critical illness, and recent contrast exposure. 1, 3
Preventive Measures
- Avoid NSAIDs entirely in at-risk patients. 3
- Ensure adequate hydration before procedures involving contrast agents. 1, 3
- Provide albumin replacement with large-volume paracentesis. 3
- Implement pharmacist-led medication review programs to identify nephrotoxic exposures. 3, 6
Follow-Up After AKI
- Schedule close post-discharge clinical evaluation within 3 months for patients with Stage 2-3 AKI to assess for resolution, new-onset CKD, or worsening of pre-existing CKD. 1, 3
- Provide patient education on avoiding over-the-counter NSAIDs and recognizing symptoms of worsening kidney function. 2, 3
- Risk stratify based on AKI severity to guide timing of nephrology follow-up. 1, 3
Critical Pitfalls to Avoid
- Delaying RRT when clear indications exist increases mortality. 1, 2
- Failing to identify and address the underlying cause leads to continued kidney damage. 1, 2
- Inappropriate continuation of nephrotoxic medications during AKI recovery causes ongoing injury. 1, 2
- Overly rapid correction of hyponatremia can lead to osmotic demyelination syndrome. 2
- Fluid overload from excessive resuscitation worsens respiratory status and tissue oxygenation. 2
- Neglecting to adjust medication dosages as kidney function changes during recovery leads to toxicities or underdosing. 2, 7