What is the appropriate emergency department workup for a patient with flank pain and a history of renal transplant (kidney transplant)?

From the Guidelines

For a patient with flank pain and a history of renal transplant presenting to the emergency department, the initial workup should prioritize a renal ultrasound to assess for hydronephrosis, perinephric collections, or vascular abnormalities, as recommended by the American College of Radiology 1. When evaluating a patient with flank pain and a history of renal transplant, it is crucial to consider the unique aspects of their condition, including the risk of transplant rejection, infection, and other complications. The workup should begin with a thorough history and physical examination, focusing on pain characteristics, urinary symptoms, fever, and medication adherence. Key components of the initial evaluation include:

• Obtaining vital signs, including temperature and blood pressure
• Laboratory tests: complete blood count, comprehensive metabolic panel with BUN and creatinine, urinalysis, and urine culture
• Checking tacrolimus or cyclosporine levels if the patient is on these medications, as their immunosuppressive regimen can impact the risk of certain complications 1
• Imaging should start with a renal ultrasound, given its advantages over other modalities, such as portability, no radiation exposure, and the lack of need for potentially nephrotoxic iodinated contrast agents 1 Consideration for non-contrast CT or CT with IV contrast may be necessary based on the clinical presentation and suspicion of specific diagnoses like kidney stones, but this should be done judiciously, taking into account the patient's renal function and the potential risks associated with contrast agents. Early consultation with transplant nephrology is essential in the evaluation process to ensure that the patient receives care tailored to their specific needs and to minimize the risk of graft dysfunction. Pain management and fluid administration should be approached with caution, avoiding NSAIDs due to their potential to worsen renal function and monitoring fluid status closely to prevent overload, which can be particularly problematic in transplant patients.

From the Research

Emergency Department Workup for Flank Pain in a Patient with a History of Renal Transplant

• The patient's history of renal transplant is crucial in determining the cause of flank pain, as transplant patients are at risk for various complications such as acute rejection, medication toxicity, and BK virus nephropathy 2.
• Ultrasound evaluation of the allograft is a critical component in the management of transplant patients and can help detect complications such as renal artery stenosis and transplant glomerulopathy 3.
• In patients presenting with acute flank pain, computed tomography (CT) has been the initial imaging method of choice, but concerns regarding radiation dose and cost-effectiveness have prompted investigations into alternative imaging algorithms, such as ultrasound and low-dose CT 4.
• Laboratory tests, including urine albumin creatinine ratio (ACR) and serum creatinine level, can help predict graft function after kidney transplant and detect early renal dysfunction 5, 6.
• A comprehensive workup for a patient with a history of renal transplant presenting with flank pain may include:
  • Ultrasound evaluation of the allograft
  • Laboratory tests, including urine ACR and serum creatinine level
  • Imaging studies, such as CT or low-dose CT, as needed
  • Review of the patient's medical history, including the transplant procedure and any previous complications 3, 2, 4, 5, 6.