What is the immediate management for a patient with acute kidney injury (AKI)?

Immediate Management of Acute Kidney Injury

Stop all nephrotoxic medications immediately—including diuretics, NSAIDs, ACE inhibitors, ARBs, and nonselective beta-blockers—as drugs account for 20-25% of AKI cases and this single intervention can prevent progression. 1, 2, 3

Step 1: Discontinue Harmful Medications (First Priority)

• Hold ALL diuretics immediately regardless of AKI type or severity 1
• Stop nephrotoxic drugs: NSAIDs, ACE inhibitors, ARBs, and vasodilators 1, 2
• Discontinue nonselective beta-blockers 4, 1
• Avoid the "triple whammy" combination (NSAIDs + diuretics + ACE inhibitors/ARBs), which dramatically increases AKI risk 1
• Adjust lactulose dosage if causing severe diarrhea 4
• Each additional nephrotoxin increases AKI odds by 53%, and combining 3+ nephrotoxins more than doubles the risk 2

Step 2: Assess Volume Status and Resuscitate

• Perform focused physical examination to determine if patient is hypovolemic, euvolemic, or hypervolemic 4, 5
• Look specifically for: signs of infection, intravascular volume depletion (dry mucous membranes, decreased skin turgor, orthostatic hypotension), or volume overload (pulmonary edema, peripheral edema) 4, 5

For Hypovolemic AKI:

• Administer albumin 1 g/kg (maximum 100g) daily for fluid resuscitation 4, 1
• Use isotonic crystalloids aggressively for severe volume depletion 1
• Monitor closely for pulmonary edema when giving albumin, as this is a life-threatening complication 4

For Euvolemic/Hypervolemic AKI:

• Avoid aggressive fluid administration 1
• Consider diuretics only after nephrotoxin withdrawal if volume overload is present 6

Step 3: Identify and Treat Precipitating Causes

• Obtain blood cultures, urine cultures, and chest radiograph if infection is suspected 1
• Start broad-spectrum antibiotics immediately when infection is strongly suspected—do not wait for culture results 1
• Perform diagnostic paracentesis in patients with ascites to evaluate for spontaneous bacterial peritonitis 1
• Obtain renal ultrasonography to rule out obstruction, particularly in older men with prostatic hypertrophy 5, 6
• Check urinalysis for hematuria, proteinuria, or abnormal sediment to exclude structural renal disease 4, 6

Step 4: Laboratory Monitoring Protocol

• Monitor daily: serum creatinine, eGFR, electrolytes (especially potassium), BUN 1, 2
• Monitor twice daily if severe AKI (stage 2-3) or rapidly changing 2
• Place bladder catheter to monitor hourly urine output in severe cases 2
• Calculate fractional excretion of sodium to differentiate prerenal from intrinsic renal causes 5, 6

Step 5: Medication Dose Adjustment

• Perform comprehensive medication reconciliation at time of AKI diagnosis 2
• Adjust all medication doses based on current GFR using validated eGFR equations 2
• Monitor therapeutic drug levels for narrow therapeutic window medications 2
• Recognize that AKI impairs hepatic cytochrome P450 activity, affecting drug metabolism beyond renal clearance 2

Step 6: Determine AKI Etiology and Stage

Classify by type:

• Prerenal (hypovolemia): responds to fluid resuscitation, fractional excretion of sodium <1% 5, 6
• Intrinsic renal (acute tubular necrosis, acute interstitial nephritis): fractional excretion of sodium >2%, muddy brown casts on urinalysis 5, 7
• Postrenal (obstruction): identified by renal ultrasonography 5, 6

Stage by KDIGO criteria:

• Stage 1: Creatinine increase ≥0.3 mg/dL within 48 hours or ≥1.5× baseline 1
• Stage 2: Creatinine ≥2× baseline 4
• Stage 3: Creatinine ≥3× baseline or initiation of renal replacement therapy 4

Critical Pitfalls to Avoid

• Never combine multiple nephrotoxins during AKI recovery phase 2
• Never restart ACE inhibitors/ARBs until GFR stabilizes and volume status is optimized 2
• Never delay essential antibiotics for life-threatening infections, even if potentially nephrotoxic 2
• Never fail to monitor for pulmonary edema when administering albumin 4
• Patients remain vulnerable to re-injury during recovery; continue nephrotoxin avoidance 1

Indications for Nephrology Consultation

• Stage 3 AKI or inadequate response to supportive treatment 6
• AKI without clear cause 6
• Preexisting stage 4 or higher chronic kidney disease 6
• Need for renal replacement therapy consideration 6
• Refractory hyperkalemia, volume overload, intractable acidosis, or uremic complications 5, 6

Recovery Phase Management

• Evaluate patients 3 months after AKI for resolution, new onset, or worsening of pre-existing CKD 1
• Continue nephrotoxin avoidance as patients remain vulnerable to re-injury 1
• Document clear medication restart plans 2
• Educate patients to avoid NSAIDs and new medications without consulting their physician 2