What is the best course of action for a 12-year-old patient with a history of trauma, now presenting with proteinuria and hematuria 5 days later, without other symptoms?

Post-Traumatic Hematuria with Proteinuria in a 12-Year-Old

This child requires renal ultrasound to evaluate for glomerular injury, as the combination of proteinuria (50 mg/dL) with 3+ hematuria 5 days post-trauma suggests a glomerular source rather than simple traumatic injury. 1

Critical Distinction: This is NOT Simple Traumatic Hematuria

The 5-day delay between trauma and urinalysis findings fundamentally changes the clinical picture. Hematuria accompanied by proteinuria (>2+ by dipstick), particularly when presenting days after trauma, suggests a glomerular source of hematuria (e.g., post-traumatic glomerulonephritis) rather than direct renal parenchymal injury. 1 Tea-colored urine and the combination of hematuria with proteinuria are hallmarks of glomerular disease. 1

Immediate Diagnostic Steps

Urinalysis with Microscopy

• Examine the urine sediment for dysmorphic red blood cells (best seen with phase contrast microscopy) and red blood cell casts, as these findings are pathognomonic for glomerular disease. 1, 2
• The presence of >80% dysmorphic RBCs strongly suggests glomerular bleeding. 2
• Red blood cell casts definitively indicate glomerular pathology. 2

Laboratory Evaluation

When glomerular disease is suspected based on proteinuria with hematuria, obtain: 1

• Blood urea nitrogen and serum creatinine
• Complete blood count with platelets
• Complement levels (C3, C4)
• Antinuclear antibody (ANA) and ANCA testing
• Spot urine calcium-to-creatinine ratio to evaluate for hypercalciuria 1

Imaging Recommendation

Renal ultrasound is the appropriate initial imaging modality. 1, 3, 2 Ultrasound serves multiple purposes in this clinical scenario:

• Displays kidney anatomy, size, and position 1
• Screens for structural lesions or pre-existing congenital anomalies 1
• Assesses kidney echogenicity (increased echogenicity suggests acute glomerulonephritis) 1
• Evaluates for kidney enlargement (common in acute glomerulonephritis) 1
• Rules out chronic changes (atrophic kidneys with altered corticomedullary differentiation indicate chronic glomerular disease) 1, 2

CT imaging is NOT indicated in this scenario. 1 The ACR Appropriateness Criteria specifically state that CT with IV contrast is appropriate for children presenting with hematuria in the acute trauma setting, particularly with macroscopic hematuria or microscopic hematuria with concerning features (hypotension, flank pain, deceleration injury). 1 However, this child is 5 days post-trauma, asymptomatic, and has proteinuria suggesting glomerular rather than traumatic etiology.

Why the Timing Matters

The 5-day interval between trauma and urinalysis is clinically significant. 4 Research demonstrates that trauma-induced proteinuria typically appears within the first 24 hours and subsides by the second post-trauma day. 4 The presence of proteinuria 5 days later suggests either:

1. A glomerular process triggered by the trauma (such as post-traumatic glomerulonephritis)
2. An incidental finding unrelated to the trauma
3. A recurrent tubular lesion pattern (though this typically occurs days 3-4 in severely injured patients) 4

Critical Pitfalls to Avoid

Do not assume this is simple traumatic hematuria requiring CT evaluation. 1 The combination of proteinuria with hematuria fundamentally changes the diagnostic approach from urologic evaluation to nephrology-focused assessment. 2

Do not perform CT urography or cystoscopy as initial evaluation. 2 These urologic evaluations are reserved for isolated hematuria without proteinuria or when non-glomerular bleeding is confirmed. 2

Do not delay nephrology referral if dysmorphic RBCs or red cell casts are present. 2 Immediate nephrology consultation is indicated for persistent significant proteinuria, presence of red cell casts or >80% dysmorphic RBCs, elevated creatinine, or hypertension. 2

If Imaging Had Been Performed Acutely

Had this child been evaluated immediately post-trauma with microscopic hematuria, the threshold for imaging would be ≥50 red blood cells per high-power field, hypotension at presentation, or concerning mechanism of injury (high-speed motor vehicle accident, deceleration injury). 1, 5 Studies demonstrate that only 4.6% of pediatric patients with blunt trauma and microscopic hematuria sustain significant renal injuries, and these typically have associated major organ injuries. 6