Editing AUA: Urotrauma (2020) (section)

===== '''Renal Trauma''' =====

* '''The kidneys are particularly prone to deceleration injuries (e.g. falls, motor vehicle collisions) because they are fixed in space only by the renal pelvis and the vascular pedicle'''
* '''Diagnosis and Evaluation'''
** '''History and physical exam'''
** '''Imaging'''
*** '''Indications for imaging (contrast enhanced CT with immediate and delayed flims) in stable trauma patients (5):'''
***# '''Gross hematuria'''
***# '''Microscopic hematuria and systolic blood pressure < 90mmHG'''
***# '''Mechanism concerning for renal injury (e.g., rapid deceleration, significant blow to flank)'''
***# '''Physical exam findings concerning for renal injury (e.g. rib fracture, significant flank ecchymosis)'''
***# '''Penetrating injury of abdomen, flank, or lower chest'''
***#* '''Generally, children can be imaged using the same criteria as adults. Children, however, often do not exhibit hypotension as adults do.'''
*** '''Modality'''
**** '''CT abdomen/pelvis with IV contrast (with immediate and delayed images) should be performed when there is suspicion of renal injury'''
***** In children, ultrasound may be used, although CT is preferred
***** '''An intraoperative one-shot IVP (2 mL/kg IV bolus of contrast with a single image obtained 10-15 minutes later) may be used to confirm that a contralateral functioning kidney is present in rare cases where the patient is taken to the operating room without preliminary CT scan''' if surgeons are considering renal exploration or nephrectomy
* '''Management'''
** '''AUA: Based on hemodynamic stability'''
*** '''If hemodynamically stable: non-invasive management'''
**** Non-invasive managment includes close hemodynamic monitoring, bed rest, ICU admission, and blood transfusion (when indicated)
**** '''Patients initially managed noninvasively may still require surgical, endoscopic, or angiographic treatments at a later time, especially those with higher grade injuries.'''
***** Although devitalized parenchyma has been suggested as a risk factor for development of septic complications, evidence supporting intervention for this radiographic finding is inconclusive.
*** '''If hemodynamically unstable: immediate intervention (surgery or angioembolization)'''
**** '''For hemodynamically unstable patients with radiographic findings of large perirenal hematoma (> 4 cm) and/or vascular contrast extravasation in the setting of deep or complex renal laceration (AAST Grade 3-5), surgeons should perform immediate intervention'''
***** Perinephric hematoma size provides a rough radiographic estimate of the magnitude of renal bleeding, and increasing hematoma size has been incrementally associated with higher intervention rates. 
**** '''Selected patients with bleeding from segmental renal vessels may benefit from angioembolization as an effective yet minimally invasive treatment to control bleeding'''
***** Selective embolization provides an effective and minimally invasive means to stop active bleeding from parenchymal lacerations and segmental arterial injury
**** '''Patients who are hemodynamically unstable despite active resuscitation should be taken to the operating room rather than angiography'''
** '''Surgical management'''
*** Nephrectomy is a frequent result when hemodynamically unstable patients undergo surgical exploration
* '''Renal injury with urinary extravasation'''
** '''Stable patients where renal pelvis or proximal ureteral injury is not suspected: observation'''
*** '''Parenchymal collecting system injuries often resolve spontaneously.'''
** '''Indications for intervention (3):'''
**# '''Presence of complications such as fever, infection, increasing pain, ileus, or fistula.'''
**# '''Suspected injury to renal pelvis or proximal ureteral avulsion'''
**#* '''Suggested by large medial urinoma or contrast extravasation on delayed images without distal ureteral contrast)'''
**# '''Urinoma increasing in size, purulence, or complexity on follow-up imaging'''
** '''Options for intervention'''
*** '''Ureteral stent (preferreed)'''
**** An internalized ureteral stent is minimally invasive and alone may provide adequate drainage of the injured kidney
**** '''A period of concomitant Foley catheter drainage may minimize pressure within the collecting system and enhance urinoma drainage'''
*** '''Percutaneous urinoma drain, percutaneous nephrostomy, or both may also be necessary'''
*** '''Mangement of injury to the renal pelvis or proximal ureteral avulsion may be endoscopic vs. open, depending on the clinical scenario'''
* '''Follow-up in patient's managed non-operatively'''
** '''Indications for follow-up CT imaging (after 48 hours) in renal trauma patients (2):''' (AUA)
**# '''Clinical signs of complications (e.g., fever, worsening flank pain, ongoing blood loss, abdominal distention)'''
**# '''Deep lacerations (AAST Grade IV-V)'''
**#* '''AAST Grade IV-V renal injuries are prone to developing troublesome complications such as urinoma or hemorrhage'''
**#* AAST Grade I-III injuries have a low risk of complications and rarely require intervention. Routine follow-up CT imaging is not advised for uncomplicated AAST Grade I-III injuries because it is not likely to change clinical management in these cases