<prompt> Which of the following is a feature of contrast induced nephropathy?Increased bilirubinIncreased creatinineDecreased creatinineDecreased bilirubin  <response>: Ref: Harrisons Principles of Internal Medicine, 18th edition, Page 2300 Table and 3241Explanation:The most common clinical course of contrast nephropathy is characterized by a rise in serum creatinine beginning 24-48 hours following exposure, peaking within 3-5 days, and resolving within 1 week. Ref: HarrisonsCONTRAST NEPHROPATHYRise in S. creatinine of atleast ImgdL within next 48 hours of contrast administration.Pathophysiologyo Hemodynamic changeso Renal tubular obstructiono Cell damage.o Immunological reactions to contrast agents.Risk Factorso Age 80 years.o Preexisting renal problems Great 2 mg dL.o DM.o Dehydration.o Solitary kidneyo Paraproteinemia.o Nephrotoxic drug usageo High contrast dose.Adequate prior HYDRATION may prevent this condition.Nonionic, low osmolar contrast media cause less renal cell damage.Sodium bicarbonate or N-acetylcysteine may decrease this.When eGFR 45 mimin1.73m2 - iodinated contrast must be avoided.Risk of Anaphylaxiso With iodinated contrast 0.24o With nonionic media- 0.04.Premedication in high risk patientso Glucocorticoids.o H2 blockers ranitidineo H1 blockerantihistaminics.High risk patients - Anaphylaxiso Prior contrast allergy.o Food allergy to shellfisho Atopy asthma or hay fever.NOTEMR contrast with gadolinium is less risky.But, when eGFR 30 mlmin. gadolinium should be avoided. 