Differential Diagnosis for Kidney Injury

• Single most likely diagnosis
  • Acute graft rejection: This is the most likely diagnosis given the patient's recent kidney transplant, fever, tenderness over the graft, and elevated creatinine levels. Acute rejection is a common complication in the first few months after transplantation and can present with decreased urine output, graft tenderness, and elevated serum creatinine.
• Other Likely diagnoses
  • Drug toxicity from mycophenolate: Mycophenolate can cause nephrotoxicity, which may lead to elevated creatinine levels. However, the presence of graft tenderness and fever makes acute rejection more likely.
  • Nephrotic syndrome: Although the urinalysis shows 2+ protein, the absence of other typical features of nephrotic syndrome (e.g., significant edema, hyperlipidemia) and the presence of graft tenderness and fever make this diagnosis less likely.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
  • Renal artery thrombosis: Although the renal ultrasound demonstrates good flow to the graft, renal artery thrombosis is a potentially life-threatening complication that requires prompt diagnosis and treatment. It is essential to consider this diagnosis, even if the ultrasound is normal, as it may not always detect thrombosis.
• Rare diagnoses
  • Other rare causes of kidney injury, such as recurrent disease (e.g., focal segmental glomerulosclerosis), de novo glomerulonephritis, or viral infections (e.g., polyomavirus), are less likely but should be considered if the more common diagnoses are ruled out.