A 45-year-old man comes to the physician for a 1-hour history of severe left flank pain. He has a 3-month history of worsening constipation. Vitals are normal. There is no dysuria. Urine dipstick shows 2+ blood. Serum studies show:
Sodium 143 mEq/L
Potassium 3.9 mEq/L
Bicarbonate 27 mEq/L
Calcium 10.4 mg/dL
Phosphate 3.0 mg/dL (NR 2.5-4.5)
Which of the following is the most likely explanation for these findings?
