Review Question - QID 215062

A 55-year-old man presents to clinic for routine health maintenance. He was recently diagnosed with transitional cell carcinoma of the bladder and is actively undergoing treatment. He has been urinating normally and denies dysuria. He takes no other medications. He has a 50 pack-year smoking history and quit 2 months ago when he was diagnosed with cancer. The patient’s temperature is 96.8°F (36.0°C), blood pressure is 144/78 mmHg, pulse is 74/min, and respirations are 16/min. Physical exam reveals a thin-appearing man with bitemporal wasting. An ultrasound reveals dilated left renal calyces and a dilated left ureter. His laboratory results are shown below:

Na+: 140 mEq/L
Cl-: 98 mEq/L
K+: 4.2 mEq/L
HCO3-: 24 mEq/L
Urea nitrogen: 14 mg/dL
Glucose: 98 mg/dL
Creatinine: 0.8 mg/dL

What changes in renal physiology most likely result from the findings seen on ultrasound?