Unexpected presentation of allograft dysfunction triggered by page kidney phenomenon immediately after kidney transplantation: a case report

BACKGROUND Page kidney phenomenon is caused by strong renal parenchymal compression and leads to renal hypoperfusion and microvascular ischemia, resulting in renal dysfunction and hypertension. Although the development of Page kidney phenomenon in allograft is rare, most of its cases are induced by allograft biopsy or trauma. We observed a case of Page kidney phenomenon that was induced by unusual causes immediately after kidney transplantation. CASE PRESENTATION A 66-year-old man, whose wife donated a kidney, underwent ABO-compatible living kidney transplantation. The allograft had three renal arteries that were trimmed and formed into one piece on the back table, and subsequently, it was anastomosed to the internal iliac artery. Intraoperative Doppler ultrasonography (US) revealed adequate blood flow of each renal artery. Urine output was also observed as soon as allograft blood flow was reperfused. After the surgery, the urine output decreased, and serum creatinine level increased to 6.0 mg/dL. Doppler US did not show evidence of acute rejection, ureteral obstruction, or anastomotic stenosis of the renal arteries. On postoperative day 7, surgical exploration was performed and revealed that the blood flow of each renal artery was adequate but subcapsular hematoma was detected at the upper pole of the allograft. Capsulotomy and hematoma evacuation were performed. Subsequently, urine output increased and serum creatinine level decreased up to 1.7 mg/dL. Allograft sample was obtained 1 h after the transplantation from the lower pole of the allograft. Although the cause of subcapsular bleeding was unclear in this case, a small cyst of the allograft, which might have ruptured during donor nephrectomy, was located in the middle of the hematoma, and oozing around the cyst was observed. CONCLUSIONS Our case indicated that the small ruptured cyst of the allograft could be the cause of subcapsular hematoma and Page kidney phenomenon. Subcapsular hematoma caused by oozing over time could be difficult to diagnose using Doppler US, and thus, other imaging modalities, such as computed tomography, should be considered. Knowledge of the Page kidney phenomenon in the allograft can lead to early diagnosis and intervention, resulting in better outcomes for recipients with allograft dysfunction.