A 44-year-old female presented to the ED with several day history of left flank pain, fever and malaise.  The patient relates a history of recurring UTIs but is on no antibiotic prophylaxis and denies history of recent hospitalization.  Her vitals signs are stable and she is noted to have a temperature of 100.8 F.  Her physical examination is only significant for left CVA tenderness.  Urinalysis reveals: >100 WBCs, 30-100 RBCs, large bacteria and a pH of 8.5.  Her creatinine was 1.3 and her WBC was 18.4. You perform a focused left renal ultrasound and note the following...

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