A 46-year-old, Caucasian, male patient presented to the emergency department suffering, for 12 hours, from acute, severe, left flank pain radiating to the left lower quadrant, with associated emesis. The patient reported minimal urine output after symptoms had started. Past medical history was unremarkable, and previous routine laboratory examinations had shown only chronic mild hyperuricemia.
The physical examination revealed mild tachypnea and left costovertebral angle tenderness, but was otherwise normal. On admission, abnormal laboratory findings included leukocytosis (17.220 white blood cells per mm3), a urinalysis showing hematuria (>100 red blood cells/high power field) and pyuria (20-22 white blood cells/high power field), and elevated values of serum creatinine (sCr) and blood urea nitrogen (BUN) (2,4 and 34 mg/dl, respectively).
What is the cause of the renal dysfunction?