What is the evaluation and treatment approach for asymptomatic hematuria in children?

Evaluation and Management of Asymptomatic Hematuria in Children

Initial Approach: Distinguish Microscopic from Macroscopic Hematuria

For isolated microscopic hematuria without proteinuria in children, no imaging is indicated initially—clinical follow-up alone is appropriate, as these patients are unlikely to have clinically significant renal disease. 1, 2

Confirm True Hematuria

• Verify ≥5 red blood cells per high-power field in 2-3 consecutive urine specimens, as dipstick positivity alone is insufficient 2
• Rule out factitious causes such as food substances (beets, blackberries) or medications that color urine without actual red blood cells 2
• Obtain urine culture to exclude urinary tract infection 2

Microscopic Hematuria Without Proteinuria

Clinical Assessment

• No imaging is warranted initially for isolated microscopic hematuria without proteinuria or dysmorphic red blood cells 1, 2
• Screen for hypercalciuria with spot urine calcium-to-creatinine ratio, as this is the most common identifiable cause (16-22% of cases) 3, 2
• Obtain family history focusing on stone disease, hearing loss (Alport syndrome), or familial renal disease 2
• Check blood pressure to screen for hypertension 2
• Assess for dysmorphic RBCs or red cell casts on microscopy, which indicate glomerular disease and warrant nephrology referral 2

Management Strategy

• Clinical follow-up with periodic urinalysis to monitor for proteinuria development is the recommended approach 2
• Screen family members' urine, as benign familial hematuria (thin basement membrane nephropathy) is common and has excellent prognosis 1, 4
• Consider renal ultrasound only if hematuria persists and remains unexplained, though diagnostic yield is low (7-9%) 1, 2
• Most children (42-81% depending on proteinuria presence) will have identifiable causes, with thin basement membrane nephropathy (15.2%) and IgA nephropathy (10.4%) being most common 5

Important Caveat

• Isolated microscopic hematuria is very rarely the presenting sign of Wilms tumor 1
• Advanced imaging (CT, MRI, IVU, VCUG) is not appropriate for initial evaluation of isolated microscopic hematuria without proteinuria 1, 2

Microscopic Hematuria With Proteinuria

Children with combined microscopic hematuria and proteinuria require comprehensive evaluation, as 81.3% have identifiable etiologies and risk of progressive kidney disease. 5

Evaluation Protocol

• Perform renal ultrasound to assess kidney size, position, and structure before considering renal biopsy 1
• Check serum creatinine and blood urea nitrogen to evaluate kidney function 2
• Obtain complete blood count with platelets 2
• Assess for dysmorphic RBCs and red cell casts, which strongly suggest glomerular disease 2
• IgA nephropathy (44.3%) is the most common cause in this population, followed by thin basement membrane disease (12.8%) 5

Management

• Refer to pediatric nephrology, as these patients may have progressive disease requiring renal biopsy 2, 4
• IgA nephropathy and thin basement membrane disease are separable only by renal biopsy, and IgA nephropathy may be progressive while thin basement membrane disease is benign 4

Macroscopic (Gross) Hematuria

For isolated asymptomatic macroscopic hematuria, renal and bladder ultrasound is the appropriate first-line imaging to exclude nephrolithiasis, urologic abnormalities, and rarely tumors. 1

Imaging Protocol

• Perform renal and bladder ultrasound as initial imaging, as gross hematuria may indicate renal or bladder tumors, hypercalciuria (22% of cases), or structural abnormalities 1, 3
• Ensure bladder is distended with urine during ultrasound to optimize assessment for polyps, masses, or vascular lesions 1
• Ultrasound is highly sensitive for detecting masses and requires no ionizing radiation 6
• If ultrasound detects a renal or bladder mass, further imaging with CT or MRI may be needed to define local extent, vascular invasion, or metastases 1

Additional Considerations

• VCUG is usually not indicated unless evaluating for suspected posterior urethral valves in males or other urethral causes (polyps, meatal stenosis) 1
• If unexplained gross hematuria persists despite negative ultrasound and bladder urothelial neoplasm is suspected, cystoscopy may be indicated 1
• Ten clinically important structural abnormalities were found per 228 children with gross hematuria in one series, warranting thorough diagnostic evaluation 3

Common Pitfalls to Avoid

• Do not assume isolated microscopic hematuria requires no follow-up—long-term monitoring is mandatory as it can rarely be the first sign of occult renal disease 3
• Do not proceed directly to CT imaging in children with hematuria, as it is not appropriate for initial evaluation and exposes children to unnecessary radiation 1, 2
• Do not overlook proteinuria assessment, as its presence fundamentally changes the evaluation and prognosis 2, 5
• Do not confuse thin basement membrane nephropathy with IgA nephropathy—only renal biopsy can distinguish them, and their prognoses differ significantly 4