A 30-year-old woman comes to the office because of a 1-day history of malaise, darkening of her skin, weakness, low back pain, and dark urine. Four days ago, she began treatment with oral trimethoprim-sulfamethoxazole for a urinary tract infection. Her temperature is 37.3°C (99.2°F), pulse is 106/min, respirations are 14/min, and blood pressure is 110/70 mm Hg. Physical examination shows scleral icterus. What is the most likely diagnosis?
1) Acute interstitial nephritis
2) Acute tubular necrosis
3) Hepatocellular injury
4) Hemolytic uremic syndrome