A Maintenance Hemodialysis Patient With Normal Perfused Renal Allograft Presenting With Hematuria and Fever: A Case Report.

Hematuria and renal dysfunction after kidney transplantation often indicate acute rejection, vascular complications, or infection. Ultrasonography, being non-invasive, convenient, and radiation-free, is a primary imaging tool. Contrast-enhanced ultrasound (CEUS) is a sensitive technique for assessing microcirculatory perfusion in the renal allograft. This report describes a 43-year-old male presenting with fever and elevated creatinine six years post-transplant. Color Doppler showed no significant abnormality in the allograft, and CEUS revealed normal perfusion. However, the patient had reached end-stage renal disease (blood urea nitrogen 35.59 mmol/L, serum creatinine 1023.70 μmol/L, cystatin C 7.80 mg/L) and had been on maintenance hemodialysis for over 4 months. The 24-hour urine output at admission was minimal (∼10 mL, used for testing), showing significant hematuria and infection (red blood cells 2700.00/μL, white blood cells 1528.00/μL, urinary microalbumin 103.10 mg/L, urinary creatinine 1287.20 μmol/L). Allograft ultrasound revealed no stones, masses, or obvious lesions. This case highlights a potential dissociation between allograft perfusion status and functional outcome - specifically, normal perfusion despite severe dysfunction and failure - suggesting a unique scenario that warrants further investigation into the mechanisms of transplant kidney dysfunction.