PMC5498204_01
Pre-transplant examinations of the abdomen by X-ray and computed tomography. A small area of calcification (arrow) in the lower pole of the right kidney not observed on the X-ray film (A) but was detected on computed tomography (B).
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Only a small area of calcification in the lower pole of the right kidney was observed by computed tomography at the time of the pre-transplant examination (Fig. 1).
Numerous spherical brownish crystals in the urinary sediment on postoperative day 3 (magnification x400).
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The renal graft started to function immediately, and a sufficient urine volume was obtained; however, the urine was already cloudy on postoperative day 3, and the analysis of the urinary sediment showed numerous spherical brownish crystals (Fig. 2).
Brown debris adhering to the double-J ureteral stent was observed on postoperative day 7.
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The brown debris adhering to the double-J ureteral stent was removed on postoperative day 7 (Fig. 3) and was identified as 2,8-DHA by infrared spectroscopy using the KBr wafer technique.
The findings of renal allograft biopsy obtained on postoperative day 7. Small crystal deposits within the tubular lumen of the renal allograft biopsy segment by conventional light microscopy (A) and polarized light microscopy (B) (magnification x400 for both). Polarized light microscopy clearly shows the crystals. Crystals deposited within the tubular lumen of the renal allograft biopsy specimen had completely disappeared by postoperative day 201.
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Similar small crystal depositions were observed within the tubular lumen in a renal allograft biopsy specimen obtained on postoperative day 7 (Fig. 4).
The clinical course after kidney transplantation. The dose of febuxostat was gradually increased until the disappearance of 2,8-DHA crystals from the urinary sediment. Maintenance therapy with febuxostat (80 mg/day) was associated with a stable renal allograft function following the disappearance of 2,8-DHA crystals from the urinary sediment and renal allograft biopsy specimens.
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Febuxostat (initial dose: 20 mg/day) was started 7 days after kidney transplantation to remove the 2,8-DHA crystals (Fig. 5). The patient's serum uric acid levels were 6.2 mg/dL before kidney transplantation, 5.0 mg/dL at postoperative day 7 before the administration of febuxostat, and 1.3 mg/dL with febuxostat (80 mg/day) (Fig. 5).