Which of the following contrast agents is preferred in a patient with decreased renal function to avoid contrast nephropathy:
High-Yield Explanation
D i.e. Low osmolar contrast - Radiocontrast agent is contraindicated in patients with previous adverse reactions to contrastQ, (excluding mild reactions like nausea and flushing), in patients with renal failure, diabetic nephropathy on metforminQ and in feeble elderly / infant patients with dehydrationQ. However, contrast agents are not contraindicated in obeseQ. - Measures recommended to reduce the incidence of contrast medium induced nephropathy include adequate hydration (most impoant safe gaurd), volume expansion with IV normal saline / or half strength sline solution, infusion of sodium bicarbonate instead of normal saline, infusion of mannitolQ, pharmacological manipulation (prostaglandin, infusion, acetyl-cystine, fenoldapam mesylate infusionQ, theophylline and replete magnesium), use of LOCM instead of HOCMQ, hemodialysis rapidly after contrast administration and avoiding sho intervals (< 48 hrs) between procedures requiring IV administration of contrast agent. - HOCM are avoided in cardiac disease (b/o high sodium content), pre-existing renal impairment (failure), myelomatosis (because HOCM are more toxic & more protein binding possibly promoting renal tubular obstruction & renal failure d/t proteinaceous casts and precipitation of Bence Jones and Tamm Horsfall protein) and hematological & metabolic conditions (HOCM may 1/t fatal sickling in sickle cell anemia). LOCM are preferred contrast agents especially if the patient has preexisting renal impairment, myelomatosis, cardiac disease and hematological & metabolic conditions like sickle cell anemiaQ.