The following clinical scenario applies to questions 1–2

A 48‐year‐old man presents to the emergency department after falling from a tree while intoxicated. He is hemodynamically stable. Physical exam is notable for some abrasions on his extremities, as well as some bruising to his left side. As part of his workup, a urinary drug screen is ordered. The urine is dilute but has a pink tinge. Portable chest x‐ray, pelvic x‐ray, and Focused Assessment with Sonography in Trauma (FAST) scan are all negative.

1. What is the next best step in management?
   
   
   
   1. Discharge from the emergency department once sober if a repeat FAST is normal at 2 hours
      
   2. Retrograde cystourethrogram
      
   3. Computed tomography scan (CT) abdomen and pelvis without contrast
      
   4. CT abdomen and pelvis with intravenous (IV) contrast and delayed images
      
   5. Renal angiogram
   
   

   Per the 2020 American Urological Association (AUA) guidelines for urotrauma, “Clinicians should perform diagnostic imaging with IV contrast‐enhanced CT in stable blunt trauma patients with gross hematuria or microscopic hematuria and systolic blood pressure < 90 mm Hg. (Standard; Evidence Strength: Grade B).” This patient’s mechanism has potential for renal injury, so when combined with gross hematuria, further assessment for renal injury is required. A renal arterial phase is typically obtained 20–30 seconds after administration of intravenous contrast, which the venous phase is seen on delays of 70–80 seconds. Urinary extravasation is best visualized on furthered delayed imaging, after about 5 minutes. Because you may not always know when to obtain delayed imaging on initial presentation, a provider who is proficient in reading CT scans should be available for immediate review of the images prior to the patient leaving the CT scanner. The results of a CT scan will guide management in regards to disposition and whether interventions are warranted.

   
   

   A normal FAST scan (Choice A) is inadequate to rule out renal injury since FAST scans will classically miss retroperitoneal blood. A retrograde cystourethrogram (Choice B) would be considered if there was specific concern for urethral trauma, such as blood at the urethral meatus or a high‐riding prostate on digital rectal exam. A CT scan without contrast (Choice C) may be the image of choice if the patient has a known anaphylactic reaction to IV contrast but provide much less information than a high‐quality contrasted study. Finally, going straight to a renal angiogram (Choice E) would be premature prior to determining the presence and/or extent of imaging on CT scan.

   
   

   Answer: D

   
   

   Morey, A. F., Brandes, S., Dugi, D. D., Armstrong, J. H., Breyer, B. N., Broghammer, J. A., … & Reston, J. T. (2014). Urotrauma: AUA guideline. The Journal of Urology , 192 (2), 327–335.

   
   

   Erlich, T., & Kitrey, N. D. (2018). Renal trauma: the current best practice. Therapeutic Advances in Urology , 10 (10), 295 – 303.

   

   
   
2. A CT scan is performed and demonstrates a parenchymal laceration that is 1.5 cm deep in the superior pole with no urinary extravasation or vascular injury. After CT scan, his heart rate is 75 beats/min with a blood pressure of 118/72 mm Hg. He’s breathing comfortably on room air with oxygen saturation of 99%. He received 50 mcg of fentanyl and 1 L of LR in the trauma bay with tolerable pain. What is the next best step in management?
   
   
   
   1. Discharge home once sober with outpatient follow‐up in 1 week
      
   2. Admit to an intermediate care unit with serial labs
      
   3. Admit to the ICU for q2h CBC and continuous bladder irrigation
      
   4. Immediate angioembolization and prophylactic ureteral stenting
      
   5. Operative exploration for attempted renorrhaphy
   
   

   This injury is consistent with an AAST grade III renal laceration in a hemodynamically stable patient. Nonoperative management, including angioembolization and/or stenting, should be the mainstay for renal trauma in a stable patient. Operative exploration decreases rates of renal salvage and should be reserved for refractory cases, so answer E in incorrect. Likewise this patient has no target (active extravasation) or indication for angioembolization given his hemodynamic stability (answer D). While many institutions will monitor patients with grade III renal lacerations in the ICU, recent literature suggests that very few (<5%) ever result in operative management, so more recent societal guideline suggest these patients can be monitored on the floor. Regardless, answer C is incorrect since there is no role for routine continuous bladder irrigation. Finally, due to potential for ongoing bleeding, some period of inpatient observation is warranted for grade III renal lacerations (answer A).

   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   

   Grade	Type	Description
   I	Contusion	Microscopic or gross hematuria. Normal urologic studies
   	Hematoma	Subcapsular, non‐expanding hematoma without parenchymal laceration
   II	Hematoma	Non‐expanding perirenal hematoma confined to the renal retroperitoneum
   	Laceration	<1.0 cm parenchymal depth of renal cortex without urinary extravagation
   III	Laceration	>1.0 cm parenchymal depth of renal cortex without urinary extravagation or collecting system rupture
   IV	Laceration	Parenchymal laceration extending through the renal cortex, medulla, and collecting system
   	Vascular	Main renal artery or vein injury with contained hemorrhage
   V	Laceration	Completely shattered kidney
   	Vascular	Avulsion of renal hilum that devascularizes kidney

   
   

   American Association for Surgery of Trauma Renal Injury Scale.

   
   

   Answer: B

   
   

   Buckley, J. C., & McAninch, J. W. (2011). Revision of current American Association for the Surgery of Trauma Renal Injury grading system. Journal of Trauma and Acute Care Surgery , 70 (1), 35 – 37.

   
   

   Erlich, T., & Kitrey, N. D. (2018). Renal trauma: the current best practice. Therapeutic Advances in Urology , 10 (10), 295 – 303.

   
   

   Keihani, S., Xu, Y., Presson, A. P., Hotaling, J. M., Nirula, R., Piotrowski, J., … & Majercik, S. (2018). Contemporary management of high‐grade renal trauma: results from the American Association for the Surgery of Trauma Genitourinary Trauma study. Journal of Trauma and Acute Care Surgery , 84 (3), 418 – 425.

   
   
3. Which of the following is true regarding high‐grade (grades IV and V) renal injury?
   
   
   
   1. A grade V renal injury is a contraindication for minimally invasive interventions, such as embolization or drainage procedures.
      
   2. High‐grade renal injuries from blunt mechanisms are more likely to result in nephrectomy than penetrating mechanisms.
      
   3. Early renal exploration results in higher rates of renal salvage.
      
   4. Renal salvage is successful in 70–80% of patients with high‐grade renal injury.
      
   5. Due to the confined location in the retroperitoneum, renal injuries, rarely if ever, result in morbidity and mortality.
   
   

   According to a 2018 study including 14 level 1 trauma centers, 431 cases of penetrating and blunt high‐grade renal injury were identified. They noted that around 80% of cases could be managed with conservative or minimally invasive approaches (embolization, percutaneous nephrostomy or drainage, or ureteral stenting); therefore, answer A is incorrect. Their reported nephrectomy rates were 0.4% for grade III, 15% for grade IV, and 62% for grade V (overall 28% for grade IV/V). The New England Trauma Consortium reported nephrectomy rates of 21% for grade IV/V, but they excluded penetrating trauma. Penetrating trauma has a much higher incidence of nephrectomy compared to blunt trauma; therefore, answer B is incorrect. One of the most important means of renal salvage is avoiding renal exploration unless it is absolutely necessary (answer C is incorrect). When intact, Gerota’s fascia will contain and tamponade most renal hematomas, but renal exploration alleviates the tamponade, which leads to more bleeding, and nephrectomy follows in many cases. This is seen when looking at National Trauma Data Bank studies that found that 30% of patients with grades I–III renal injuries who required laparotomy underwent nephrectomy. Finally, high‐grade renal lacerations can lead to many complications, including urinoma, urinary fistulae, infection, continued hemorrhage, and death (answer E), so nonoperative management is not always appropriate.

   
   

   Answer: D

   
   

   Erlich, T., & Kitrey, N. D. (2018). Renal trauma: the current best practice. Therapeutic Advances in Urology , 10 (10), 295 – 303.

   
   

   Keihani, S., Xu, Y., Presson, A. P., Hotaling, J. M., Nirula, R., Piotrowski, J., … & Majercik, S. (2018). Contemporary management of high‐grade renal trauma: results from the American Association for the Surgery of Trauma Genitourinary Trauma study. Journal of Trauma and Acute Care Surgery , 84 (3), 418 – 425.

   
   

   McClung CD, Hotaling JM, Wang J, Wessells H, & Voelzke BB. (2013). Contemporary trends in the immediate surgical management of renal trauma using a national database. The Journal of Trauma and Acute Care Surgery , 75 (4), 602–606.

   
   
4. A 55‐year‐old woman is involved in a motorcycle collision. She is hemodynamically stable upon presentation and has a negative FAST scan. Secondary survey reveals bruising to the right flank and diffuse tenderness but no significant injuries. Trauma labs are sent, and a CT abdomen/pelvis with IV contrast is normal. A plan is made to discharge the patient from the ER. Prior to discharge, the ER provider calls to inform you the urinalysis demonstrated 4+ blood with >50 red blood cells per high power field (RBC/HPF), although the urine sample was clear. What is the next best step in management?
   
   
   
   1. Proceed with discharge with close interval outpatient follow‐up with a urologist or primary care doctor
      
   2. Send a creatinine kinase
      
   3. Repeat a CT abdomen/pelvis with and without IV contrast and delayed images
      
   4. Admit the patient for observation overnight with q4 hour labs
      
   5. Perform an MRI of the kidneys
   
   

   Microscopic hematuria is defined as three or more RBC/HPF in adults and over 50 RBC/HPF in pediatric patients with no visible blood in the urine sample. Visible hematuria is seen in 35–77% of renal trauma cases. It is important to note there is no correlation between the degree of hematuria with the renal injury. The above case has a stable patient with microscopic hematuria. In the absence of renal injury on imaging, this would be classified as a renal contusion or grade I injury, of which no immediate intervention is warranted. In the absence of other findings, the patient can be discharged home with close interval follow‐up with either a primary care provider or urologist to ensure the microscopic hematuria clears and doesn’t represent another pathology, such as an undiagnosed genitourinary malignancy. While myoglobinuria can interfere with the urinalysis dipstick, the visualization of RBC under microscope definitively diagnoses true hematuria, so a creatinine kinase is not needed (answer B). A repeat CT scan would subject the patient to an additional contrast dose with limited diagnostic benefit, especially in light of normal vitals on presentation, so answer C is incorrect. Admission for microscopic hematuria alone is unnecessary (answer D). Finally, renal MRI has no role in the initial trauma evaluation in the presence of a normal CT scan, so answer E is incorrect.

   
   

   Answer: A

   
   

   Erlich, T., & Kitrey, N. D. (2018). Renal trauma: the current best practice. Therapeutic Advances in Urology , 10 (10), 295 – 303.

   
   

   Morey, A. F., Brandes, S., Dugi, D. D., Armstrong, J. H., Breyer, B. N., Broghammer, J. A., … & Reston, J. T. (2014). Urotrauma: AUA guideline. The Journal of Urology , 192 (2), 327 – 335.

The following scenario applies to questions 5 and 6