A 64-year-old woman with a 15-year history of hypertension and type 2 diabetes mellitus presents to the emergency department with acute onset left flank pain and gross hematuria. Blood pressure is 168/94 mmHg, heart rate 92 bpm, respirations 16/min, temperature 37°C, and oxygen saturation 98% on room air. Laboratory studies show serum creatinine 1.8 mg/dL (baseline 0.9 mg/dL), BUN 38 mg/dL, and urinalysis with 3+ blood and no proteinuria or casts. CT angiography of the abdomen demonstrates severe stenosis of the left renal artery with thrombus at the site of stenosis. The left kidney measures 7 cm in length, compared to the right kidney at 10.5 cm. Which of the following best explains the reduction in left kidney size?

1. A)Acute tubular necrosis from contrast-induced nephropathy during CT angiography
2. B)Chronic ischemic injury from prolonged renal artery stenosis causing nephron lossGABARITO
3. C)Acute pyelonephritis with suppurative destruction of renal parenchyma
4. D)Diabetic glomerulosclerosis with progressive proteinuric kidney disease
5. E)Reflux nephropathy from vesicoureteral reflux causing chronic pyelonephritis