AKI algorithm

Question 1

Step 1
You have an elevated creatinine
Compare it to the baseline, is it and AKI or CKD?

Answer 1

Serum creatinine elevated at baseline/did not meet KDIGO definition of AKI => CKD

Serum creatinine >1.5x baseline or
Greater than 26.5umol/l or
Greater than 0.3 mg/dL in 48hours
Go to Step 2

Question 2

Step 2
Is there a post renal cause
Do a kidney USS, is there an obstruction?

Answer 2

Obstruction present => post renal cause
-catheterise, investigate and address this

No obstruction => Step3

Question 3

Step 3

Does the history, examination, investigations, urinalysis support a presently or intrinsic cause?

Answer 3

Prerenal cause => give IV fluid challenge
-if responsive, provide supportive therapy

If unresponsive => intrinsic cause
Go to Step 4

Question 4

Step 4, suspected intrinsic cause
Perform a urinalysis and blood tests
Review past procedures

Answer 4

ATN if

• ischemic
• nephrotoxic drugs (aminoglycosides, contrast, statins)
• myoglobin from rhabdomyolysis
• muddy brown casts, proteinuria

Glomerulonephritis if

• Antiglomerular basement membrane disease autoantibodies
• ANCA antibodies found (cANCA, pANCA)
• post infective
• immune complex GN (lupus)
• nephritic, nephrotic syndromes
• RBC casts, proteinuria, fatty casts (if nephrotic)

Interstitial nephritis

• drugs (NSAIDS, PPIs, penicillin)
• local infection
• systemic autoimmune disease (sjogrens, lupus)
• WBC casts

Vascular
-obstruction from thromboembolism