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

Evaluation of Gross Hematuria in Pediatric Patients

Begin with renal and bladder ultrasound as the initial imaging modality for all children presenting with gross hematuria, after completing urinalysis with microscopic examination to differentiate glomerular from non-glomerular causes. 1, 2

Initial Clinical Assessment

History Elements to Elicit

• Recent streptococcal infection (post-infectious glomerulonephritis) 2
• Family history of renal disease, hearing loss (Alport syndrome), or stone disease 2
• Sickle cell disease, bleeding disorders, or coagulopathies 2
• Recent trauma (even minor trauma to anomalous kidneys can cause significant injury) 1, 2
• Strenuous exercise (can cause transient hematuria) 2
• Dysuria, frequency, flank pain (suggests infection or stones) 2
• Medications that may cause hematuria 2
• Tropical exposure, bloody diarrhea, joint pains, rash (systemic disease) 2

Physical Examination Priorities

• Fever, arthritis, rashes, soft-tissue edema (glomerulonephritis) 2
• Nephromegaly or abdominal masses (Wilms tumor concern) 2
• Costovertebral angle tenderness (pyelonephritis or stones) 2
• Blood at urethral meatus (urethral injury, especially with pelvic trauma) 1
• Deafness (Alport syndrome) 2
• Height and weight (indicators of chronic disease) 2

Laboratory Evaluation

Essential Initial Testing

• Complete urinalysis with microscopic examination is the single most important diagnostic test 2, 3
• Examine for dysmorphic red blood cells (>80% indicates glomerular source) 2
• Look for red blood cell casts (pathognomonic for glomerular disease) 2
• Assess for proteinuria (suggests glomerular disease) 2
• Check for white cells and microorganisms (urinary tract infection) 2

Additional Laboratory Tests When Indicated

• Spot urine calcium-to-creatinine ratio (hypercalciuria is common cause, found in 22% of gross hematuria cases) 2, 4
• Blood urea nitrogen, serum creatinine, complete blood count with platelets (if chronic kidney disease suspected) 2
• Urine culture if infection suspected 1

Imaging Approach

First-Line Imaging

Ultrasound of kidneys and bladder is the initial imaging modality of choice for isolated gross hematuria 1, 2

• Displays kidney anatomy effectively and screens for structural lesions 2
• No ionizing radiation exposure 2
• Can be performed without anesthesia or contrast 5
• Evaluates for congenital anomalies (present in 13% of pediatric gross hematuria cases) 6

Concurrent Plain Radiography

• May be performed alongside ultrasound to detect calcifications and radiopaque stones 2
• Radiography has 59% sensitivity for stone detection 1

When to Consider CT

• Painful hematuria with negative ultrasound and high clinical suspicion for urolithiasis, especially if detection would impact treatment 2
• Gross hematuria following trauma requires contrast-enhanced CT of abdomen and pelvis 1, 2
• All CT scans must be performed with intravenous contrast unless specifically contraindicated 1, 2
• CT has sensitivity and specificity both >90% for stone detection 2

Special Clinical Scenarios

Traumatic Hematuria

• Gross hematuria with trauma mandates radiologic evaluation with contrast-enhanced CT 1, 2
• Isolated microscopic hematuria without clinical/laboratory findings of visceral trauma or concerning mechanism does not need emergency investigation 1, 2
• Radiologic evaluation indicated when ≥50 RBCs present on urinalysis, patient hypotensive on presentation, or based on mechanism of injury 1, 2
• Blood at urethral meatus with pelvic fractures requires retrograde urethrography before catheter placement (50% incidence of genitourinary injury) 1, 2
• Minor trauma to anomalous kidney (1-4% of population) can cause major clinical repercussions 1, 2

Hematuria with Palpable Abdominal Mass

This scenario requires urgent ultrasound evaluation immediately, as it raises concern for Wilms tumor 2, 5

• Ultrasound confirms renal origin of mass, assesses contralateral kidney, evaluates for inferior vena cava involvement 2, 5
• After ultrasound confirms renal mass, proceed urgently to chest CT for staging 2, 5
• Consider contrast-enhanced abdominal CT or MRI to define local extent and vascular invasion 2

Glomerular vs. Non-Glomerular Hematuria

Tea-colored urine with proteinuria, red blood cell casts, and dysmorphic RBCs (>80%) indicates glomerular source 2

• Glomerular causes found in approximately 29% of pediatric gross hematuria cases 3
• Most common glomerular cause is IgA nephropathy 3, 4
• Non-glomerular causes are more than twice as common as glomerular diseases 3
• Most common non-glomerular causes: hypercalciuria (22%), urethrorrhagia (especially in boys), hemorrhagic cystitis 3, 6, 4

Common Etiologies by Frequency

Most Common Causes in Pediatric Gross Hematuria

• Hypercalciuria (22% of cases) 4
• Benign urethrorrhagia (19% of male patients) 6
• Trauma (14% of cases) 6
• Urinary tract infection (14% of cases) 6
• IgA nephropathy (most common glomerular cause) 3, 4
• Congenital urologic anomalies (13% of cases) 6
• Urolithiasis (5% of cases) 6

No Etiology Found

• Approximately 34-38% of pediatric gross hematuria cases have no identifiable cause after complete evaluation 3, 6
• Long-term prognosis for these patients appears to be good, with only rare recurrences 3

Critical Pitfalls to Avoid

Do Not Delay Imaging When Mass Present

Assuming isolated hematuria requires no workup when an abdominal mass is palpable is a critical error 2

• Isolated microscopic hematuria is very rarely the presenting scenario of Wilms tumor 2
• However, gross hematuria with abdominal mass requires urgent evaluation 2, 5

Avoid Unnecessary Advanced Imaging

• Advanced imaging (CT, MRI, VCUG) is not appropriate for isolated, transient microscopic hematuria in otherwise well children 2
• Exposes children to unnecessary risk without clinical benefit 2

Do Not Rely on Hypotension in Children

• Hypotension is an unreliable clinical indicator for prompting imaging in pediatric trauma patients 1, 2

Cystoscopy Indications Are Limited

• Reserve cystoscopy for persistent hematuria or ambiguous imaging findings 6
• Not part of routine initial evaluation in most pediatric cases 6

When to Refer

Nephrology Referral Indicated For:

• Persistent hematuria with proteinuria 2
• Red blood cell casts or >80% dysmorphic RBCs 2
• Elevated creatinine or declining renal function 2
• Hypertension with hematuria 2

Urology Referral Indicated For:

• Stones >5mm or not passing spontaneously 7
• Anatomic abnormalities requiring surgical intervention 7
• Gross hematuria originating from urinary tract without identified cause after complete evaluation 7