Chapter 12: Contrast-Induced Nephropathy
A 52-year-old woman with past medical history of type 2 diabetes mellitus, hypertension, hyperlipidemia, and chronic kidney disease presents with acute onset of chest discomfort, dyspnea, and diaphoresis while gardening. In the emergency department, serum troponin is noted to be elevated with ST depression noted in the lateral leads of an electrocardiogram (EKG). On examination, vital signs are blood pressure of 140/94 mm Hg, pulse rate 92 beats/min, and oxygen saturation of 99% on room air. Physical examination is unremarkable aside from decreased breath sounds noted at the bases bilaterally.
Lab work is notable for creatinine of 2.2 mg/dL and an eGFR of 35 mL/min/1.73 m2. The patient is to be admitted and made nothing by mouth after midnight in preparation for left heart catheterization in the morning. What should be your next step in the medical management of this patient?
A. Begin oral N-acetylcysteine.
B. Provide prophylactic hemodialysis prior to the procedure.
C. Begin therapy with a statin.
D. Provide volume expansion with intravenous isotonic normal saline.
The answer is D. Prophylactic hemodialysis has not been demonstrated to prevent CIN. The prophylactic value of statins is limited by size and demand of studies of statin’s value in this setting. Thus date too preliminary to recommend statins as prophylaxis for CIN at present time. Although many studies of N-acetylcysteine on prophylaxis of CIN, some are positive and others negative. No consensus on value of N-acetylcysteine with some guidelines recommending use while others do not recommend this agent. There is universal agreement that volume expansion with intravenous saline is the single most important prophylactic measure for prevention of CIN.
A 56-year-old man with past medical history of type 2 diabetes mellitus and chronic kidney disease presents to the hospital with complaint of chest tightness and worsening dyspnea on exertion. The patient is diagnosed with ST-elevation myocardial infarction and undergoes emergent left-sided heart catheterization. He had percutaneous coronary intervention with bare metal stent placement for 99% lesion of the left anterior descending artery. Two days after the procedure, he is noted to have abnormal lab work. Basic metabolic panel reveals creatinine of 2.2 mg/dL (admission creatinine of 1.6 mg/dL). Urinalysis is obtained and shows trace protein, 0–1 red blood cells and 0–1 white blood cells. Urine sediment is evaluated and shows muddy brown granular casts. What of the following is the correct diagnosis?
A. Acute interstitial nephritis
B. Contrast-induced nephropathy
D. Cholesterol crystal embolism