Acute Kidney Injury Management

Definition and Diagnosis

AKI is diagnosed when serum creatinine increases by ≥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, according to Clinical Gastroenterology and Hepatology 1
The American College of Cardiology recommends staging the severity using KDIGO criteria (Stage 1-3), with Stage 3 representing the most severe form requiring intensive intervention 2

Prerenal AKI is the most common cause in hospitalized patients, resulting from inadequate renal perfusion, as stated by Clinical Gastroenterology and Hepatology 1
Intrinsic Renal AKI can be caused by acute tubular necrosis (ATN) from prolonged ischemia or nephrotoxic exposures, according to Clinical Gastroenterology and Hepatology 1
Postrenal AKI occurs rarely but must be excluded early, with causes including prostatic hypertrophy, urethral stricture, bilateral ureteral obstruction, or bladder outlet obstruction, as noted by Praxis Medical Insights 3

The American Heart Association recommends immediately stopping all nephrotoxic medications, including NSAIDs, aminoglycosides, ACE inhibitors, ARBs, and diuretics, to prevent further kidney damage 2
The National Kidney Foundation suggests obtaining a detailed history, performing urinalysis with microscopy, and checking urine sodium and fractional excretion of sodium to differentiate prerenal from intrinsic causes 1
The European Renal Association recommends obtaining renal ultrasound immediately to rule out obstruction, especially in older males with prostatic symptoms 2

For Stage 1 AKI, the American College of Physicians recommends continuing nephrotoxic medication discontinuation and volume optimization, monitoring serum creatinine and electrolytes daily, and reassessing medication dosing requirements 3
For Stage 2 AKI, the National Institute of Diabetes and Digestive and Kidney Diseases suggests intensifying monitoring to every 4-6 hours for creatinine, BUN, and electrolytes, increasing frequency of clinical assessments for fluid overload, and preparing for potential need for renal replacement therapy 2
For Stage 3 AKI, the Kidney Disease: Improving Global Outcomes (KDIGO) guidelines recommend monitoring electrolytes, BUN, and creatinine every 4-6 hours, and urgent indications for renal replacement therapy include severe oliguria, refractory hyperkalemia, severe metabolic acidosis, volume overload, and uremic complications 2

The American Association for the Study of Liver Diseases recommends initiating HRS-AKI treatment when serum creatinine remains >2× baseline despite volume repletion, with albumin 1 g/kg IV on day 1 and vasoactive agents such as terlipressin or octreotide plus midodrine or norepinephrine 1
The European Association for the Study of the Liver suggests performing diagnostic paracentesis in all cirrhotic patients with AKI to evaluate for spontaneous bacterial peritonitis, holding diuretics and nonselective beta-blockers, and administering albumin 1 g/kg/day for 2 days if creatinine doubles from baseline 1

The American College of Cardiology recommends avoiding NSAIDs entirely in at-risk patients, avoiding excessive or unmonitored diuretic use, providing albumin replacement with large-volume paracentesis, ensuring adequate hydration before contrast procedures, and implementing pharmacist-led medication review programs to identify nephrotoxic exposures 1
The National Kidney Foundation suggests identifying high-risk patients, including those with advanced age, pre-existing chronic kidney disease, diabetes mellitus, heart failure, sepsis or critical illness, and recent contrast exposure 2

The American College of Physicians recommends scheduling close 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, and providing patient education on avoiding over-the-counter NSAIDs and recognizing symptoms of worsening kidney function 2
The National Institute of Diabetes and Digestive and Kidney Diseases suggests continuing to adjust medication dosages as kidney function changes during recovery, monitoring for development of chronic kidney disease, and risk stratifying based on AKI severity to guide timing of nephrology follow-up 5