Nephrotic Range Proteinuria as a Manifestation of Transplant Renal Artery Stenosis in Kidney Transplant Recipient

Transplant renal artery stenosis (TRAS) is a common vascular complication after kidney transplantation. It usually presents with worsening hypertension, fluid retention, and renal allograft dysfunction. Nephrotic range proteinuria has not been reported as a manifestation of TRAS, although renal artery stenosis (RAS) in native kidneys can cause heavy proteinuria. Here, we present the case of a 73-year-old female with history of chronic kidney disease from diabetic nephropathy. She developed renal allograft dysfunction associated with nephrotic range proteinuria of about 7 g/day 4 months after deceased donor kidney transplantation. Work-up for renal allograft dysfunction, including 2 kidney allograft biopsies and extensive serological evaluation was negative. Renal allograft Doppler ultrasonography revealed TRAS. The patient underwent percutaneous angioplasty with subsequent normalization of kidney function and improved proteinuria to 0.5 g/day. Three months later, the patient developed recurrent TRAS with worsening kidney function and increased proteinuria to 1.5 g/day. After repeat angioplasty, the proteinuria subsided to a level of about 0.2 g/day. She continued to have stable kidney function with serum creatinine in the 1.2-1.3 mg/dL and proteinuria in the 0.2-0.3 g/day range since then. We believe our case demonstrates that nephrotic range proteinuria could be a rare and unusual presentation of TRAS.