A 68-Year-Old Woman Comes to the Physician with Increasing Fatigue

A 68-year-old woman comes to the physician with increasing fatigue and shortness of breath for 2 weeks. She has only passed very small amounts of urine over the past few days. During this time, she has also noticed that her feet appear unusually puffy for a few hours every morning. She has a 6-month history of lower back and thoracic pain, for which she takes ibuprofen daily. Her only other medication is a laxative for constipation, which she first experienced 8 months ago. Her temperature is 37.9°C (98.9°F) , pulse is 110/min, respirations are 22/min, and blood pressure is 150/100 mm Hg. Laboratory results are as follows: Renal biopsy is performed and light microscopy shows atrophic tubules, many of which contain large, obstructing, waxy casts that stain intensely with eosin.  Which of the following is the most likely diagnosis in this patient?

A) Acute pyelonephritis
B) Aminoglycoside toxicity
C) Hypersensitivity interstitial nephritis
D) Ischemic tubular necrosis
E) Lead nephropathy
F) Multiple myeloma
G) Nonsteroidal anti-inflammatory drug-associated nephropathy
H) Papillary necrosis
I) Urate nephropathy