Approach to the patient with acute kidney allograft dysfunction >1 week posttransplantation

CNI: calcineurin inhibitor; dd-cfDNA: donor-derived cell-free DNA; DSA: donor-specific anti-HLA antibody; BKPyV: BK polyomavirus; ACE: angiotensin-converting enzyme; ARB: angiotensin-receptor blocker.
* A serum creatinine that is higher than expected may be seen in the setting of recently transplanted patients whose serum creatinine is not decreasing as quickly as expected after transplantation.
¶ New or increasing proteinuria greater than 1 g/day after transplantation is also indicative of allograft dysfunction. We generally perform a kidney allograft biopsy in all kidney transplant recipients who present with proteinuria greater than 1 g/day, regardless of the serum creatinine concentration, if not otherwise contraindicated.
Δ Medications of interest include ACE inhibitors and ARBs, which can be associated with prerenal acute kidney injury, and nondihydropyridine calcium channel blockers and azole antifungal agents, which interact with CNIs and can increase whole blood CNI levels.
◊ Refer to other relevant UpToDate content about complicated urinary tract infection in kidney transplant recipients.
§ dd-cfDNA is a biomarker for the detection of acute allograft rejection. Practice may vary at other transplant centers. Some centers do not yet routinely measure plasma dd-cfDNA levels, while other centers do not begin checking plasma dd-cfDNA levels until 1 month posttransplantation.
¥ In patients presenting with acute allograft dysfunction, detection of a de novo DSA or a significant rise in DSA in patients with a preexisting DSA is concerning for the possibility of antibody-mediated rejection.
‡ In patients with a plasma BKPyV viral load ≥10,000 copies/mL, a presumptive diagnosis of BKPyV-associated nephropathy is frequently made if no other causes of allograft dysfunction are identified.
† For patients who live far away from their respective transplant centers, some centers routinely order a kidney allograft ultrasound as part of the initial evaluation of kidney allograft dysfunction.
** Urinary obstruction may be treated with a ureteral stent or drainage of a perinephric fluid collection, if present. Transplant renal artery stenosis should be managed with angioplasty of the transplant renal artery.