ABSTRACT
We report a case that a 68-year-old man taking hydroxyurea for essential thrombocythemia produced milky urine during propofol infusion. Under microscopic analysis, the cloudy urine sample was revealed to comprise uric acid crystals. Postoperatively, kidney function such as urine output and blood urea nitrogen to creatinine ratio showed no abnormality. We suggest that the cloudy urine may be due to the increased excretion of uric acid after administration of propofol. Although this rare case of cloudy milky urine is resolved on its own, we need to consider the possibility of such urine color changes. It is particularly important to understand that medication, preoperative serum uric acid level, urine pH, and the hypothermal operating room can change the color of urine through the presence of uric acid crystals.
