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Hematuria in Children

Definition

• Gross hematuria: red blood cells visible to the naked eye, confirmed by urine dipstick for blood.
• Microscopic hematuria: clear yellow urine with a positive urine dipstick, confirmed as >5 RBCs/high-power field on a freshly spun specimen. For microscopic hematuria to be considered significant, it should be found on >2 separate occasions.

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Epidemiology

• Isolated microscopic hematuria occurs in approximately 1% of school-age children.
• < 25% of these children will have hematuria on repeated testing; most resolve spontaneously within 1 year.
• Gross hematuria is rarer, accounting for ~0.1–0.13% of pediatric emergency visits.
• A definitive diagnosis is established in < 30% of isolated microscopic hematuria cases.

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Causes

BOX: Causes of Hematuria in Children (Campbell Walsh Wein Urology)

Most Common Diagnoses in Gross Hematuria (pediatric ED):

1. UTI (26%)
2. Perineal irritation (11%)
3. Trauma (7%)
4. Meatal stenosis with ulceration (7%)
5. Coagulation abnormalities (3%)
6. Nephrolithiasis (2%)
7. Less common: sickle cell disease/trait, glomerular disease, malignancy, benign idiopathic urethrorrhagia

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Initial Evaluation

History

• Painless vs. painful, intermittent vs. persistent, gross vs. microscopic
• Associated symptoms: trauma, abdominal pain, fever, dysuria, voiding dysfunction, rash, joint pain, weight gain/edema, headaches, visual changes
• Family history: hematuria, bleeding disorders, hearing loss, urolithiasis, sickle cell disease, renal disease

Physical Examination

• Blood pressure (hypertension suggests glomerular disease)
• Rashes, joint abnormalities, edema
• Abdominal/flank tenderness or masses
• Perineal abnormalities

Urine Examination — Critical First Step

• Dysmorphic / "crenated" RBCs → glomerular disease
• Normal RBC morphology → lower urinary tract bleeding
• RBC casts → defines glomerulonephritis
• Crystals → urolithiasis
• WBCs/bacteria → UTI

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Evaluation Framework

Isolated Microscopic Hematuria (asymptomatic, no proteinuria, unremarkable family history)

• Test parents for hematuria
• Measure urinary calcium excretion (spot urine Ca/Cr ratio)
• Renal ultrasound yield is low; do only if hematuria persists for several months with relevant clinical findings
• Voiding cystourethrogram and cystoscopy are NOT indicated
• Observe and retest in 6–12 months

Microscopic Hematuria with Positive History/Abnormal Findings

• CBC, serum electrolytes, creatinine, albumin
• C3, C4 (complement levels)
• ASO titer / anti-DNase B (post-streptococcal GN)
• ANA (lupus nephritis)
• Quantitative urine protein (protein/creatinine ratio)
• Individualized: hearing screen (Alport syndrome), hemoglobin electrophoresis (sickle cell), imaging, genetic testing

Glomerular Disease Suspected (proteinuria + hypertension + edema)

• Baseline renal function, electrolytes, CBC, albumin, C3/C4, ASO
• Refer to pediatric nephrologist

Gross Hematuria

1. Thorough history + exam
2. Urinalysis + urine culture
3. Renal sonogram
4. If persistent with no identifiable cause → cystoscopy with retrograde pyelograms
5. If cause still not apparent (especially with proteinuria) → refer to pediatric nephrologist

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Diagnostic Flowchart

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Specific Conditions

IgA Nephropathy (Berger Disease)

• Most common glomerulonephritis worldwide
• Occurs most commonly in children and young adults, male predominance
• Classic: gross hematuria 1–2 days after upper respiratory infection ("synpharyngitic hematuria")
• Normal complement levels; diagnosis by biopsy (mesangial IgA deposits)

Post-Streptococcal Glomerulonephritis (PSGN)

• UA shows hematuria ± RBC casts + proteinuria ± pyuria
• Low C3, normal C4
• ASO titer elevated

Alport Syndrome

• X-linked hereditary nephritis; think of it with family history of progressive renal disease + hearing loss + ocular abnormalities
• Thin GBM on biopsy

Hypercalciuria

• A common cause of isolated hematuria; spot urine Ca/Cr > 0.2 mg/mg is abnormal
• Predisposes to nephrolithiasis

Benign Idiopathic Urethrorrhagia

• Bloody spotting of underwear in prepubertal/pubertal boys
• Mean age ~10 years; up to one-third have concomitant dysuria
• Urine culture and renal US uniformly normal
• Management: watchful waiting — >90% resolve within 2 years
• If persists beyond 2 years: retrograde urethrography or cystoscopy (evaluate for urethral stricture)
• Note: these boys are at increased risk for urethral stricture — minimize instrumentation

Nutcracker Syndrome

• Compression of the left renal vein between the aorta and superior mesenteric artery → gross hematuria
• Diagnosed by Doppler ultrasound or CT angiography

Wilms Tumor

• Should be considered in a child with gross hematuria + abdominal mass
• Renal ultrasound or CT for evaluation

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Indications for Renal Biopsy

• Persistent hematuria + significant proteinuria
• Hematuria + hypertension
• Hematuria + decreased GFR
• Hematuria + systemic disease features (rash, arthritis, complement abnormalities)
• Family history of progressive renal disease

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Key Points Summary

• Isolated microscopic hematuria → ~1% of school-age children; mostly benign, resolves in 1 year
• "Tea-colored" urine + RBC casts → glomerular origin; refer to pediatric nephrology
• Gross hematuria + no RBCs on microscopy + positive dipstick → think hemoglobinuria/myoglobinuria
• UTI is the most common cause of gross hematuria in children
• Cystoscopy and VCUG are not routine for isolated microscopic hematuria
• Supratherapeutic anticoagulation can cause hematuria; therapeutic levels do not

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