What is the treatment for acute kidney injury?

Treatment of Acute Kidney Injury

The cornerstone of AKI treatment is immediate discontinuation of all nephrotoxic medications, optimization of volume status with isotonic crystalloid resuscitation for hypovolemia, and initiation of renal replacement therapy when life-threatening complications develop (severe oliguria unresponsive to fluids, refractory hyperkalemia, uremic symptoms, or severe metabolic acidosis). 1, 2

Immediate Drug Management

Stop all nephrotoxic medications immediately upon AKI diagnosis, as drugs account for 20-25% of AKI cases in hospitalized and critically ill patients 3, 4:

• Discontinue NSAIDs, ACE inhibitors, ARBs, and diuretics during the acute phase when GFR is unstable 5, 3, 2
• Avoid the "triple whammy" combination (NSAIDs + diuretics + ACE inhibitors/ARBs), which more than doubles AKI risk 3, 2
• Each additional nephrotoxin increases AKI odds by 53% 3, 2
• Hold vasodilators and beta-blockers to maintain renal perfusion 2

Adjust all remaining medications based on current GFR using validated equations, as AKI impairs both renal clearance and hepatic cytochrome P450 activity 5, 3

Volume Status Optimization

Assess volume status clinically (jugular venous pressure, skin turgor, mucous membranes, orthostatic vitals) and through laboratory markers 1, 2:

For Hypovolemic Patients:

• Administer isotonic crystalloids as first-line therapy for volume expansion 2, 6
• Target mean arterial pressure ≥65 mmHg to ensure adequate renal perfusion 2
• In cirrhotic patients with ascites, give IV albumin 1 g/kg for two consecutive days 2
• Avoid hydroxyethyl starches due to increased AKI risk 2

For Volume-Overloaded Patients:

• Use diuretics only for managing volume overload, not for preventing or treating AKI itself 2
• Never use furosemide in hemodynamically unstable patients, as it precipitates further renal hypoperfusion 2
• Consider earlier initiation of renal replacement therapy to achieve negative fluid balance 7

Renal Replacement Therapy Indications

Initiate RRT urgently when any of the following develop 1, 6:

• Severe oliguria unresponsive to fluid resuscitation
• Refractory hyperkalemia
• Severe metabolic acidosis (intractable)
• Uremic complications (encephalopathy, pericarditis, pleuritis)
• Volume overload refractory to diuretics
• Certain toxin removal

Individualize RRT timing based on overall clinical condition rather than creatinine thresholds alone 2

Diagnostic Workup

Obtain renal ultrasound immediately to rule out obstructive uropathy, especially in older males with prostatic hypertrophy 1, 8:

• Measure serum creatinine, BUN, and electrolytes every 4-6 hours initially 1
• Perform urinalysis to detect hematuria, proteinuria, or abnormal sediment 1, 8
• Calculate fractional excretion of sodium to differentiate prerenal from intrinsic causes 6
• Monitor urine output hourly with bladder catheter in severe cases 3

Do not use eGFR equations (MDRD, CKD-EPI) to assess kidney function during acute AKI, as they are inaccurate in this setting 2

Supportive Care Measures

Optimize nutritional status and glycemic control to support recovery 8:

• Implement strict input/output monitoring 1
• Monitor electrolytes (especially potassium) daily to twice daily 3
• Track therapeutic drug levels for narrow therapeutic window medications 3

ACE Inhibitor/ARB Management Nuance

The evidence on ACE inhibitor/ARB discontinuation is nuanced: While guidelines recommend holding these agents during acute AKI when GFR is unstable 5, 3, two studies showed increased 30-day mortality when these drugs were not restarted post-surgery, possibly from hypertensive rebound causing cardiac decompensation 5. Restart ACE inhibitors/ARBs only after GFR stabilizes and volume status is optimized 5, 3.

Nephrology Consultation Criteria

Consult nephrology for 8:

• Stage 3 or higher AKI
• Inadequate response to supportive treatment after 48 hours
• AKI without clear etiology
• Preexisting stage 4 or higher CKD
• Need for renal replacement therapy

Critical Pitfalls to Avoid

Never combine multiple nephrotoxins, particularly the triple whammy combination 3, 2:

• Avoid macrolide-statin combinations due to rhabdomyolysis risk from CYP3A4 inhibition 3
• Do not delay RRT when clear indications exist, as this increases mortality 1
• Avoid overly aggressive fluid administration in non-hypovolemic patients, which worsens outcomes 5, 1
• Never fail to adjust medication dosages as kidney function changes during recovery 5
• Do not continue nephrotoxic medications during the recovery phase 5

Recovery Phase Management

Continue nephrotoxin avoidance during recovery to prevent re-injury 2:

• Perform dynamic medication reconciliation at all care transitions 5
• Reassess drug dosing frequently as GFR changes 5, 3
• Educate patients to avoid over-the-counter NSAIDs 5
• Document clear medication restart plans 3