A 66-year-old man comes to the clinic for a routine physical examination. He has chronic kidney disease, diabetes mellitus, hypercholesterolemia, and hypertension. His medications include aspirin, atorvastatin, hydrochlorothiazide, and metformin. The patient has smoked 2 packs of cigarettes daily for the past 22 years. His temperature is 37.2 C (99 F), blood pressure is 140/90 mm Hg, pulse is 80/min, and respirations are 12/min. Physical examination shows a palpable abdominal mass, and auscultation shows a bruit below his umbilicus. A CT angiogram with intravenous iodinated contrast is performed. His creatinine level on the day of the scan was 1.8 mg/dL and 2 days later was 2.6 mg/dL. Which of the following would most likely have prevented this complication in the patient?

Question

A 66-year-old man comes to the clinic for a routine physical examination.  He has chronic kidney disease, diabetes mellitus, hypercholesterolemia, and hypertension.  His medications include aspirin, atorvastatin, hydrochlorothiazide, and metformin.  The patient has smoked 2 packs of cigarettes daily for the past 22 years.  His temperature is 37.2 C (99 F), blood pressure is 140/90 mm Hg, pulse is 80/min, and respirations are 12/min.  Physical examination shows a palpable abdominal mass, and auscultation shows a bruit below his umbilicus.  A CT angiogram with intravenous iodinated contrast is performed.  His creatinine level on the day of the scan was 1.8 mg/dL and 2 days later was 2.6 mg/dL.  Which of the following would most likely have prevented this complication in the patient?

Quizplus · Accepted Answer

Explanation: 11ec2b69_c09a_49fc_8f63_0fa0dd62e27b_MD0005_00 This patient with chronic kidney disease developed acute kidney injury (AKI) after exposure to iodinated contrast. Contrast-induced nephropathy (CIN) refers to AKI seen within 2-3 days of contrast exposure and lasts about 5-7 days. Impaired renal function (estimated glomerular filtration rate <40 mL/min/1.73 m² or serum creatinine >1.5 mg/dL) and volume depletion are important risk factors. Contrast-induced renal vasoconstriction is the proposed mechanism of injury. Intravenous volume expansion with isotonic solution (sodium chloride or sodium bicarbonate) is the only intervention that has been shown consistently to reduce the risk of contrast-induced acute kidney injury. The efficacy of oral hydration or oral sodium bicarbonate is unclear. This is likely due to these measures not rapidly expanding intravascular volume to effectively counter renal vasoconstriction (Choices C and E). N-acetylcysteine has also been used to prevent CIN but has not been shown to be superior to intravenous saline or sodium bicarbonate. (Choice A) Hemodialysis does not counter effects of contrast media on the kidney once exposure has occurred. Therefore, it does not reduce the risk of contrast nephropathy and is not recommended. (Choice B) Adjusting the diuretic dose to increase urine flow does not prevent contrast nephropathy. Diuretics may cause volume depletion that can increase the risk of contrast nephropathy. As a result, diuretics are usually held around the time of the contrast study, particularly in patients at high risk of AKI. Metformin should also be held to avoid risk of metformin-associated lactic acidosis Educational objective: Contrast-induced renal vasoconstriction is thought to cause contrast-induced nephropathy (CIN). Patients at high risk of CIN should receive intravenous sodium chloride or sodium bicarbonate infusion before and after contrast exposure to prevent renal hypoperfusion. References: Contrast-induced acute kidney injury and renal support for acute kidney injury: a KDIGO summary (part 2). (http://www.ncbi.nlm.nih.gov/pubmed/23394215)

A 66-Year-Old Man Comes to the Clinic for a Routine