Cloudy urine developed during total intravenous anesthesia with 2% propofol in the patient taking hydroxyurea -A case report-

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. Although low urine pH and low temperature are known to increase the potential for urine discoloration after propofol administration, the incidence is very low. Furthermore, no cases of urine discoloration relating to the patient's medication have been reported. Here, we report on the development of cloudy urine during general anesthesia using total intravenous anesthesia (TIVA) with 2% propofol in a patient taking hydroxyurea. CASE REPORTA 68-year-old man with cervical herniated nucleus pulposus was scheduled for anterior cervical discectomy and fusion. The patient had been taking diltiazem and ramipril for hypertension, metformin for diabetes mellitus, and hydroxyurea for essential thrombocythemia. TIVA was planned as intraoperative motorevoked potentials monitoring was required. General anesthesia was induced and maintained with target controlled infusion of 2% propofol and remifentanil, in addition to neuromuscular blockade with rocuronium. Cloudy urine was observed 2 h after the initiation of anesthesia (Fig. 1). A urine sample was collected for analysis. Although the urine was cloudy, the drainage of urine was good and vital signs were within normal ranges. Therefore, we did not disrupt the operation and maintained anesthesia using TIVA while observing the urine.The color of urine became progressively clearer over time. In urine sample collected during anesthesia we observed crystals consistent with uric acid under the microscope (Fig. 2). Urine cultures were negative and renal function test results were within normal ranges. However, the serum uric acid level decreased from 6.3 mg/dl to 4.0 mg/dl postoperatively. The urine sample was subjected to a drug test, ultraperformance liquid chromatography-tandem mass spectrometry, and only ￭Case Report￭

Propofol-Associated Urine Discoloration: Systematic Literature Review

“…Sixty-seven articles were published in English, six in Spanish, two in Dutch, one in Korean, and one in Turkish. The mentioned publications documented 95 cases of propofol-associated discoloration (and no case of fospropofol-associated discoloration): 54 (57%) with a green urine discoloration [2,, 32 (34%) with a pink-cloudy urine discoloration [3,[60][61][62][63][64][65][66][67][68][69][70][71][72][73][74][75][76][77][78], and nine (9.5%) with a non-urinary green discoloration [46,[79][80][81][82][83][84][85][86]. Completeness of reporting was satisfactory in 33 (35%), good in 35 (37%), and excellent in 27 (28%) cases.…”

“…A pink-cloudy urine discoloration was reported in 32 cases with a median age of 27 years [3,[60][61][62][63][64][65][66][67][68][69][70][71][72][73][74][75][76][77][78]]. An excessive body weight, an acidic urine pH, and increased uric acid excretion were documented in many cases (Table 3).…”