genitourinary disorders
Contrast Nephropathy
Introduction
Contrast nephropathy is worsening of renal function after IV administration of radiocontrast and is usually temporary. Diagnosis is based on a progressive rise in serum creatinine 24 to 48 hours after contrast is given. Treatment is supportive. Volume loading with isotonic saline before and after contrast administration may help in prevention. (See also Overview of Tubulointerstitial Diseases .) Contrast nephropathy is Acute Tubular Necrosis (ATN) caused by an iodinated radiocontrast agent, all of which are nephrotoxic. However, risk is lower with newer contrast agents, which are nonionic and have a lower osmolality than older agents, whose osmolality is about 1400 to 1800 mOsm/kg (or mmol/kg). For example, second-generation, low-osmolal agents (eg, The precise mechanism of radiocontrast toxicity is unknown but is suspected to be some combination of renal vasoconstriction and direct cytotoxic effects, perhaps through formation of reactive oxygen species, causing acute tubular necrosis. Most patients have no symptoms. Renal function usually later returns to normal. 