What testing should I do for a patient with hematuria after a scrotal injury?

Diagnostic Testing for Hematuria After Scrotal Injury

For a patient with hematuria following scrotal injury, ultrasound should be performed as the initial imaging test, followed by additional studies based on severity of hematuria and clinical findings. 1

Initial Assessment

• Determine if hematuria is gross (macroscopic) or microscopic, as this affects the diagnostic pathway 1
• Assess for signs of testicular rupture such as scrotal ecchymosis, swelling, or difficulty identifying testicular contours on physical exam 1
• Check for blood at the urethral meatus, which would suggest urethral injury 1
• Evaluate for signs of hypotension or other signs of significant trauma 1

Diagnostic Algorithm

Step 1: Scrotal Ultrasound

• Perform ultrasound as the first-line imaging test for all patients with scrotal trauma and hematuria 1
• Look for specific findings such as loss of testicular contour and heterogeneous echotexture of parenchyma, which suggest testicular rupture 1

Step 2: Additional Testing Based on Hematuria Severity

For Gross Hematuria:

• Contrast-enhanced CT scan of abdomen and pelvis is required to evaluate for upper urinary tract injury 1
  • If renal injury is detected, obtain delayed scans to evaluate for collecting system disruption 1
• If blood is present at the urethral meatus:
  • Perform retrograde urethrography before bladder catheter placement 1
  • Consider cystogram to exclude concomitant bladder injury 1

For Microscopic Hematuria:

• If >50 red blood cells per high-power field:
  • Consider imaging of the urinary tract, especially with other concerning findings 1
• If <50 red blood cells per high-power field and no other concerning findings:
  • Observation may be appropriate as microscopic hematuria alone is a poor predictor of significant genitourinary tract damage 2

Step 3: Additional Considerations

• If pelvic fractures are present with hematuria, there is a high risk (50%) of genitourinary injury 1
  • CT cystography should be performed to evaluate for bladder rupture 1
• If testicular rupture is suspected on ultrasound, surgical exploration is indicated 1
• For patients with equivocal signs of penile injury, ultrasound may help confirm or exclude diagnosis 1

Important Caveats

• Regular ultrasound has limited sensitivity (41%) for renal injuries; contrast-enhanced CT is superior for evaluating renal trauma 1
• Intravenous urography (IVU) has no role in current practice for evaluation of hematuria in hemodynamically stable patients 1
• Even if initial workup is negative, follow-up may be necessary as hematuria can be the only sign of underlying genitourinary pathology 3, 4
• Avoid relying solely on the degree of hematuria to determine the need for imaging in pediatric patients, as there is only a fair correlation between hematuria severity and risk of renal injury 1

Follow-up Testing

• For moderate to severe renal injuries (AAST III-V), follow-up imaging is driven by clinical condition 1
• Uretroscopy or uretrogram are the methods of choice for follow-up of urethral injuries 1
• Return to sports activities should only be allowed after microscopic hematuria has resolved 1