What is the appropriate evaluation and management of a pediatric patient presenting with hematuria (blood in urine)?

Evaluation and Management of Pediatric Hematuria

The appropriate evaluation of pediatric hematuria requires a systematic approach based on clinical presentation, with initial focus on confirming true hematuria, differentiating between glomerular and non-glomerular causes, and determining the need for imaging based on specific clinical scenarios. 1, 2

Initial Assessment

• Confirm true hematuria by verifying ≥5 red blood cells per high-power field in 2-3 consecutive urine specimens, as dipstick positivity alone is insufficient 3
• Investigate factitious causes of "hematuria" such as food substances or medications that may color the urine without actual red blood cells 1
• Obtain thorough history focusing on:
  • Family history of stone disease, hearing loss, sickle cell disease, hemophilia, or familial renal disease 1
  • Recent trauma, viral illness, or streptococcal infection 1, 3
  • Presence of symptoms such as flank pain, frequency, dysuria 1

Urine Evaluation

• Assess for proteinuria, which if present (>2+ by dipstick) suggests glomerular disease and requires more extensive evaluation 1, 3
• Look for red blood cell casts and dysmorphic red blood cells (using phase contrast microscopy), which suggest glomerular source of hematuria 1, 3
• Evaluate for hypercalciuria with a spot urine calcium-to-creatinine ratio, as this is a common cause of microscopic hematuria in children (16-22% of cases) 3, 4
• Obtain urine culture to rule out urinary tract infection 1

Laboratory Testing

• Basic laboratory screening should include:
  • Serum creatinine and blood urea nitrogen to evaluate kidney function 1
  • Complete blood count with platelets 1
  • If suggested by initial workup, consider more advanced testing for glomerulonephritis and vasculitis 1

Clinical Scenarios and Management

1. Isolated Microscopic Hematuria without Proteinuria

• Clinical follow-up is recommended without immediate imaging, as these patients are unlikely to have clinically significant renal disease 1, 3
• Most common causes include thin basement membrane nephropathy and idiopathic hypercalciuria 3, 4
• Periodic urinalysis to monitor for development of proteinuria and blood pressure monitoring are recommended 3, 5

2. Microscopic Hematuria with Proteinuria

• More extensive evaluation is warranted, including renal ultrasound to assess kidney size and structure 1, 3
• Consider nephrology referral as this combination suggests glomerulonephritis 2, 5
• Consider audiogram and slit lamp examinations if there is suspicion for Alport syndrome 1

3. Painful Hematuria

• Suggests urolithiasis, urinary tract infection, or trauma 1, 2
• Renal ultrasound is the preferred initial imaging modality 1

4. Macroscopic (Gross) Hematuria

• Requires more thorough evaluation than microscopic hematuria 2, 4
• Ultrasound is the best initial imaging modality to display anatomy, size, and position of the kidneys 1
• In a study of 228 children with gross hematuria, 22% had hypercalciuria and 10 patients had clinically important structural abnormalities 4

Imaging Recommendations

• For isolated microscopic hematuria without proteinuria: no imaging is indicated initially 1, 3
• For microscopic hematuria with proteinuria: renal ultrasound is recommended 1, 3
• For painful hematuria: renal ultrasound is the preferred initial imaging 1
• For post-traumatic hematuria: imaging is needed to identify evidence and extent of renal or urinary tract injury 1
• CT imaging is not appropriate in the initial evaluation of isolated microscopic hematuria without proteinuria in children 3

Important Clinical Considerations

• Most children with isolated microscopic hematuria have a benign course and do not require extensive workup 3, 4
• Asymptomatic microscopic hematuria is common in children (0.25% to 1.0% in children 6 to 15 years of age) 1
• The presence of dysmorphic red blood cells and red cell casts strongly suggests glomerular disease and warrants nephrology referral 2, 3
• Persistent unexplained microscopic hematuria should be monitored for at least 6-12 months before considering renal biopsy 5
• Hypercalciuria is one of the most common identifiable causes of both microscopic (16%) and gross hematuria (22%) in children 4

Common Pitfalls to Avoid

• Failing to confirm true hematuria with microscopic examination 3, 6
• Extensive imaging for isolated microscopic hematuria without proteinuria, which has low diagnostic yield 1, 3
• Neglecting to evaluate for hypercalciuria, which is a common cause of hematuria in children 3, 4
• Missing glomerular disease by not assessing for proteinuria, dysmorphic RBCs, or RBC casts 1, 2
• Overlooking family history that might suggest hereditary conditions like Alport syndrome or thin basement membrane nephropathy 1, 3