We recently had a case of pediatric GU injury after blunt trauma. This inspired me to write a piece on GU injuries. Enjoy!
Most GU injuries are a result of blunt trauma. Up to 10% of patients in the ED with abdominal trauma will have GU injuries. They are often missed and can be very subtle in their initial presentation, therefore, it’s important to keep a high index of suspicion!!
The GU system is assessed as part of the secondary survey. External genitalia should be examined for any signs of ecchymosis or bleeding. In males, the urethral meatus should be inspected for signs of blood. In females, an external genital exam should be done to look for signs of labial injury or bleeding at the introitus. The perineum should be examined in all patients. Perineal injuries should NOT be probed, as this may cause a dislodgement of a clot, which may lead to exsanguination. A rectal exam, though no longer warranted in all trauma patients, is still important to perform in patients in whom you suspect a GU injury. The presence of a high-riding or boggy prostate denotes urethral injury. The 8th edition of ATLS recommended, “digital rectal exam be performed selectively before inserting an indwelling urinary catheter.” However, the DRE since then has been downplayed, the sensitivity of abnormal prostate position for urethral injury has been quoted as low as 2%.
The “F” in the ABCDEF of trauma is Foley catheter. All patients of major trauma should have a Foley catheter placed. If there are signs of a potential urethral injury in a male, Foley placement should be delayed until after a retrograde urethrogram is performed (RUG). (RUG in females is not useful because the urethra is comparatively very short).
((How to perform an RUG: place an unlubricated urinary catheter 2-3 cm into the distal urethra. Inflate the balloon with 1-2ml of water. Next, inject 20-30mL of contrast through the Foley catheter. Take the X-ray when the last 10mL of contrast is being pushed.))
Once a Foley is placed… the question is… is there hematuria? And how much hematuria is concerning? Gross hematuria is a sign of bladder or renal injury and should be further worked up, namely via cystography and/or CT scan. Microscopic hematuria is deemed as clinically insignificant in trauma. Extensive data exists supporting doing nothing and following up in 1-2 weeks to ensure the hematuria has cleared. Imaging is not recommended in these cases unless the hematuria is persistent. Keep in mind that the Foley insertion itself can cause microscopic hematuria (greater than 5 RBCs per high-power field). However, we still perform urinalysis on these patients. Why? Because gross hematuria IS an indication for radiographic evaluation, but physicians are not great at identifying gross hematuria with the naked eye. Peacock et al. in the Journal of Trauma 2001, concluded that in 95% of cases, clinicians were able to detect hematuria only after samples contained more than 3,500 RBCs per hpf. These interpretations were independent of profession, specialty and level of training.
What about pediatric patients? Traditional teaching is to work up pediatric patients for GU injuries if there are >50 RBCs in the urine. Satucci et al. in the Journal of Urology, did a retrospective review of 720 patients and concluded that all patients (except one) with significant renal injuries either had gross hematuria, hypotension or a significant deceleration mechanism. Therefore, according to this study, the imaging criteria for adults may also be applied to the pediatric population. This comes with a warning: just keep in mind, that not all GU injuries present with gross hematuria and the pediatric kidney is much more vulnerable to injury as compared with adults. Based on a retrospective study of 180 patients, renal injury was increased to 8% when microscopic hematuria was greater than 50 RBC per hpf and to 32% with gross hematuria. In short, renal injury CAN be present with microscopic hematuria, so concerning signs (flank ecchymosis, associated intra-abdominal injury) should be taken seriously when considering imaging for pediatric patients.
The gold standard of imaging for urethral injuries is retrograde urethrogram, for bladder injury is cystography, for renal and ureteral injuries, CT with IV contrast.
References:
Mark Bisanzo et al. Emergency Management of the Trauma Patient. Lippincott Williams&Wilkins. Baltimore, 2007.
Arpilleda et al. Evidence-Based Management of Pediatric Genitourinary Tract Injuries in the ED. May 2010; 7 (5).
sadia.hussain
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1 Comment
Richard.Shin · October 26, 2013 at 9:17 pm
For testicular trauma gold standard is surgical exploration, but US can be an adjunct for diagnosis.