Differential Diagnosis for Post-PCNL Patient

Single Most Likely Diagnosis

• Post-renal acute kidney injury (AKI) due to obstruction: The patient's elevated creatinine level (2.4) on post-op day 3 after a PCNL procedure for a large renal stone suggests that there might be an obstruction in the urinary tract, possibly due to a residual stone fragment, blood clot, or ureteral stent malfunction. This is a common complication following PCNL and aligns with the patient's symptoms of nausea and weakness.

Other Likely Diagnoses

• Sepsis: Although the patient's WBC count is only mildly elevated (10,500), the recent history of a surgical procedure and the presence of a foreign body (if a stent was placed) increase the risk of infection. Sepsis can cause AKI, nausea, and weakness.
• Hemorrhage or significant blood loss: The patient's hemoglobin (HgB) is at the lower end of the normal range (11), and given the recent surgical history, there could be ongoing blood loss contributing to the patient's weakness and potentially affecting renal function.
• Prerenal AKI due to dehydration: Nausea can lead to dehydration, which in turn can cause prerenal AKI, especially in a post-surgical patient who may have increased fluid losses.

Do Not Miss Diagnoses

• Septic shock: While the patient's current presentation does not strongly suggest septic shock, missing this diagnosis could be fatal. Any sign of infection in a post-surgical patient warrants immediate attention.
• Retroperitoneal hemorrhage: A significant and potentially life-threatening complication of PCNL, which could present with nonspecific symptoms like nausea and weakness, especially if the patient is on anticoagulation or has a coagulopathy.
• Pulmonary embolism: Although less directly related to the PCNL procedure, pulmonary embolism is a significant risk in any post-surgical patient and can present with nonspecific symptoms.

Rare Diagnoses

• Contrast-induced nephropathy: If the patient received contrast during the procedure or in the post-operative period for imaging, contrast-induced nephropathy could be a consideration, although the timing (post-op day 3) makes it less likely.
• ATN (Acute Tubular Necrosis) from medications or toxins: Certain medications or toxins could cause ATN, but without additional history (e.g., medication use), this remains a less likely consideration.
• Vascular injury or AV fistula: Direct vascular injury during PCNL is rare but could lead to significant complications, including hemorrhage or fistula formation, which might present with delayed onset of symptoms.