What is the appropriate evaluation and management of hematuria in pediatric patients?

Evaluation and Management of Pediatric Hematuria

Initial Clinical Assessment

Begin with a focused history targeting specific red flags that determine the diagnostic pathway and urgency of evaluation. 1, 2

Critical Historical Elements to Elicit

• Recent streptococcal infection (suggests post-infectious glomerulonephritis) 1, 2
• Family history of renal disease, hearing loss, or sickle cell disease (raises concern for hereditary nephropathies like Alport syndrome or thin basement membrane disease) 1, 2
• Recent trauma or strenuous exercise (may cause transient benign hematuria) 1, 2
• Urinary symptoms: dysuria, frequency, flank pain, or foul-smelling urine (suggests UTI or urolithiasis) 1, 2
• Systemic symptoms: fever, rash, arthritis, joint pain, or bloody diarrhea (indicates systemic disease like Henoch-Schönlein purpura or lupus) 1, 2
• Medications or substances that may color urine without true hematuria 1

Physical Examination Priorities

• Measure height and weight as indicators of chronic disease 1, 2
• Assess blood pressure (hypertension suggests glomerular disease) 1, 2
• Palpate for abdominal masses or nephromegaly (critical red flag for Wilms tumor requiring urgent imaging) 2, 3
• Examine for costovertebral angle tenderness (suggests pyelonephritis) 1, 3
• Look for rashes, arthritis, soft-tissue edema, or deafness (indicates systemic or hereditary disease) 1, 2
• Inspect genitalia for signs of trauma or abuse 1

Urinalysis: The Critical Differentiating Step

Thorough urinalysis with microscopic examination is the only laboratory test uniformly required and fundamentally determines the diagnostic pathway. 1, 2

Glomerular vs. Non-Glomerular Differentiation

Tea-colored urine with proteinuria (>2+ by dipstick), red blood cell casts, and dysmorphic red blood cells (best seen with phase contrast microscopy) indicate glomerular hematuria. 1, 2

White blood cells and microorganisms in urine indicate urinary tract infection, which directs care by different criteria. 1, 2

Additional Urinary Studies

• Spot urine calcium-to-creatinine ratio to evaluate for hypercalciuria 1, 2
• Urine culture if infection is suspected, preferably before antibiotics 2, 3
• Use clean-catch or catheterization rather than bag collection due to high false-positive rates 3

Laboratory Workup When Chronic Kidney Disease Suspected

• Blood urea nitrogen, serum creatinine, and complete blood count with platelets 1, 2
• If glomerulonephritis suspected: complement levels (C3, C4), ANA, ANCA 2
• If Alport syndrome suspected: audiogram and slit lamp examination 1, 2

Imaging Strategy: Clinical Scenario-Dependent

Isolated Microscopic Hematuria Without Proteinuria

No imaging is indicated for children with isolated microscopic hematuria (≥5 RBCs per high-powered field) without proteinuria or dysmorphic red blood cells, as they are unlikely to have clinically significant renal disease. 1, 2

• A study of 325 pediatric patients with microscopic hematuria found no clinically significant findings on renal ultrasound (87% underwent) or voiding cystourethrography (24% underwent) 1, 2
• Many patients are followed clinically without extensive workup 1
• Screening family members' urine may be useful for benign familial hematuria or thin basement membrane nephropathy 1, 2

Isolated Macroscopic (Gross) Hematuria

Ultrasound of the kidneys and bladder is the initial imaging modality of choice, as it effectively displays kidney anatomy and screens for structural lesions. 2

• Plain radiography may be performed concurrently to detect calcifications and radiopaque stones 2
• Ultrasound is critical for assessing kidney size as an indicator of chronicity before potential renal biopsy 1, 2

Painful Hematuria (Suspected Urolithiasis)

Ultrasound of the kidneys and bladder is first-line imaging, though it has limited sensitivity for ureteral stones. 2

CT may be particularly useful with negative ultrasound and high clinical suspicion for urolithiasis, especially if detection would impact treatment. 2

• CT has sensitivity and specificity both well above 90% for stone detection with proper low-dose techniques 2

Post-Traumatic Hematuria

Macroscopic hematuria following trauma necessitates contrast-enhanced CT of the abdomen and pelvis to identify extent of renal or urinary tract injury. 1, 2

All CT scans must be performed with intravenous contrast unless specifically contraindicated. 2

Isolated microscopic hematuria without clinical findings of visceral trauma does not need emergency investigation. 2

• Radiologic evaluation is indicated when ≥50 red blood cells are present on urinalysis, when the patient is hypotensive, or based on mechanism of injury 2
• Blood at urethral meatus with pelvic fractures warrants investigation of urethra and bladder (50% incidence of genitourinary injury) 2

Critical Red Flag: Hematuria with Palpable Abdominal Mass

Urgent ultrasound evaluation is required, as this raises concern for Wilms tumor or other renal masses, fundamentally changing the clinical scenario. 2

Ultrasound confirms renal origin, assesses the contralateral kidney, evaluates for inferior vena cava involvement, and determines tumor size and extent. 2

After ultrasound confirms a renal mass, proceed urgently to chest CT for staging and consider contrast-enhanced abdominal CT or MRI to define local extent and vascular invasion. 2

When to Refer to Pediatric Nephrology

Immediate nephrology referral is indicated for: 2, 3

• Hematuria with proteinuria, red blood cell casts, or >80% dysmorphic RBCs (glomerular disease)
• Hematuria that does not resolve within 2 weeks of onset of glomerulonephritis
• Persistent microscopic hematuria with development of hypertension
• Elevated creatinine or declining renal function
• Need for renal biopsy (necessary for definitive diagnosis of IgA nephropathy, Alport syndrome, or other glomerular diseases) 1, 2

Critical Pitfalls to Avoid

Never perform advanced imaging (CT, MRI, or VCUG) for isolated, transient microscopic hematuria in an otherwise well child—this exposes the child to unnecessary risk. 2

Delaying imaging by assuming isolated hematuria requires no workup is critical when an abdominal mass is present. 2

Isolated microscopic hematuria is very rarely the presenting scenario of Wilms tumor; brief, self-limited findings should not trigger oncologic concerns. 2

Do not proceed directly to CT without ultrasound confirmation of renal origin in cases with abdominal mass. 2

Minor trauma to an anomalous kidney can cause major clinical repercussions, as renal anomalies occur in 1-4% of the population. 2