Q. A 35-year-old woman presents to the emergency department with right flank pain, nausea, and vomiting. She denies any fever, chills, dysuria, or hematuria. She does not have a significant medical history and her medications include only oral contraceptives. On examination, she appears uncomfortable and with mild tenderness in the right flank region. Her vital signs are normal. Urinalysis is negative for leukocyte esterase and nitrites and with no red blood cells are present. The patient undergoes a renal ultrasound, which reveals moderate right-sided hydronephrosis. What is the next best step in the management in this case?