Management of Acute Kidney Injury

Initial Assessment and Diagnosis

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

Discontinue all nephrotoxic medications (NSAIDs, aminoglycosides, contrast agents) 1, 2
Hold ACE inhibitors, ARBs, diuretics, and adjust beta-blockers as needed 4, 5
Adjust dosages of all medications based on current estimated GFR 2
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

For Stage 1 AKI, continue interventions from Step 2 and monitor serum creatinine and urine output closely 1
For Stage 2 AKI, intensify monitoring of renal function and electrolytes, and check for changes in drug dosing requirements 1, 2, 6
For Stage 3 AKI, implement more intensive monitoring of renal function, electrolytes, and acid-base status, and consider RRT for refractory hyperkalemia, severe metabolic acidosis, volume overload unresponsive to diuretics, uremic symptoms, or certain toxin ingestions 1, 2
For Hypovolemic/Prerenal AKI, administer isotonic fluids cautiously with close monitoring 2
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) 4

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

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 6, 7
Risk stratification based on AKI severity should guide timing of outpatient follow-up 5, 6
Provide patient education regarding medication avoidance, especially over-the-counter NSAIDs 2