Q. A 65-year-old male presents to the emergency department complaining of fever and chills that began yesterday. He reports three episodes of vomiting last night, and describes a two-week history of “burning” when he urinates and increased frequency of urination. He denies any rashes or lesions, and states that otherwise he has been “eating, pooping, and sleeping like a champ”. His past medical history is significant for well-controlled hypertension, moderate hyperlipidemia, and gout. His medications are diltiazem 180 mg daily, atorvastatin 20 mg daily, and colchicine 0.6 mg prn. On physical examination, his temperature is 39 degrees Celsius (102.2 Fahrenheit), heart rate 80/min, respiratory rate 22/min, blood pressure 130/90 mm Hg. Physical examination demonstrates an unremarkable cardiopulmonary assessment. There is significant right-sided costovertebral angle tenderness noted, with no overlying rashes or lesions. Digital rectal examination reveals a smooth, non-tender, enlarged prostate measuring 2 to 3 fingerbreadths. A dipstick urinalysis shows dark, cloudy, brown urine positive for blood, nitrites, and leukocyte esterase. You order the urine to be sent to the laboratory for further analysis and culture. You also order blood work. Laboratory Results: Complete Blood Count Leukocyte Count 18,000 mm3 Hemoglobin 14 g/dL Hematocrit 45 percent Platelets 200,000 mm3 Liver Function Test Alanine aminotransferase 20 U/L Aspartate aminotransferase 24 U/L Amylase 40 U/L Total Proteins 7 g/dL Total Bilirubin 0.9 mg/dL Albumin 4.0 g/dL Based on the information you have at this time, what is the most likely diagnosis?