New Terminology for Contrast-Enhanced Nephropathy
The term "Contrast-Induced Nephropathy (CIN)" is being replaced with "Contrast-Induced Acute Kidney Injury (CI-AKI)" or "Post-Contrast Acute Kidney Injury (PC-AKI)" in contemporary medical literature. 1, 2
Rationale for Terminology Change
The shift in terminology reflects evolving understanding of the condition's pathophysiology and clinical significance:
CI-AKI is now the preferred term because it more accurately describes the acute kidney injury that occurs following contrast administration, moving away from the older "nephropathy" designation which implied a more chronic process 1, 2
The term change acknowledges that recent evidence has questioned whether contrast media directly causes kidney injury in many cases, with multiple propensity score-matched analyses of over 60,000 patients showing no significantly enhanced AKI risk with contrast-enhanced versus unenhanced CT 3
A systematic review demonstrated similar risks of AKI, dialysis initiation, and mortality between enhanced and unenhanced CT, challenging the traditional concept of CIN 3
Clinical Definition Remains Consistent
Regardless of terminology, the diagnostic criteria are standardized:
CI-AKI is defined as a rise in serum creatinine ≥0.5 mg/dL (44 μmol/L) or ≥25% from baseline at 48 hours after contrast exposure (or 5-10% at 12 hours) 1, 4, 5
The condition typically presents as nonoliguric acute kidney injury, with creatinine levels peaking at 2-3 days and returning to baseline within 7-10 days in most cases 6
Important Clinical Context
The concept of contrast-induced kidney injury has been significantly questioned based on contemporary evidence, suggesting that exaggerated fear of radiocontrast nephropathy could lead to withholding beneficial diagnostic studies 3
In cancer patients specifically, CI-AKI prevalence was 9% with pre-existing kidney disease (50% had irreversible injury) and approximately 5% without kidney disease, though these risks must be weighed against diagnostic benefits 3
Patients with CKD G4-G5 remain at highest risk (13.6% incidence), but stable ambulatory outpatients have lower risk compared to sick inpatients with similar GFR 3