What is the approach to managing pediatric hematuria (blood in the urine)?

Approach to Pediatric Hematuria

Initial Clinical Evaluation

Begin with a meticulous history focusing on specific red flags: recent streptococcal infection, family history of renal disease or hearing loss (Alport syndrome), sickle cell disease, bleeding disorders, urolithiasis, recent trauma, strenuous exercise, menstruation, dysuria, flank pain, and medications that may cause hematuria. 1

Key Historical Elements to Elicit:

• Urinary tract infection symptoms, tropical exposure, bloody diarrhea, joint pains, rash, frequency, and dysuria 1
• Occult trauma, foreign body insertion, family history of stone disease, hearing loss, and hypertension 1
• Factitious causes including food substances or medicines that color urine without actual red blood cells 1

Physical Examination Priorities:

• Assess for fevers, arthritis, rashes, soft-tissue edema, nephromegaly, abdominal masses, genital or anal bleeding suggesting abuse, deafness, and costovertebral angle tenderness 1
• Measure height and weight as indicators of chronic disease 1

Urinalysis: The Critical Differentiating Step

Perform thorough urinalysis with microscopic examination to differentiate glomerular from non-glomerular causes, as this fundamentally determines the diagnostic pathway. 1, 2

Glomerular Hematuria Indicators:

• Tea-colored urine with proteinuria (>2+ by dipstick), red blood cell casts, and dysmorphic red blood cells on phase contrast microscopy suggest glomerulonephritis 1
• The combination of hematuria and proteinuria requires rapid systematic evaluation, generally including renal biopsy, except when post-streptococcal glomerulonephritis can be clearly documented 3

Non-Glomerular Hematuria Indicators:

• Presence of white cells and microorganisms indicates urinary tract infection 1
• Evaluate for hypercalciuria using spot urine calcium-to-creatinine ratio 1

Initial Laboratory Workup:

• When chronic kidney disease is suspected, obtain blood urea nitrogen, serum creatinine, and complete blood count with platelets 1
• If glomerulonephritis is suspected, perform advanced assessment for vasculitis, and obtain audiogram and slit lamp examination if Alport syndrome is considered 1

Clinical Scenario-Based Imaging Approach

Isolated Microscopic Hematuria (Asymptomatic, Non-traumatic):

For transient microscopic hematuria in an otherwise well child, no imaging or further workup is required, as patients without proteinuria or dysmorphic red blood cells are unlikely to have clinically significant renal disease. 4

• A large study of 325 pediatric patients with microscopic hematuria found no clinically significant findings on renal ultrasound or voiding cystourethrography, supporting conservative management 4
• Imaging is only indicated if hematuria becomes persistent (present in 2 or 3 of 3 consecutive properly collected specimens) or if the child develops macroscopic hematuria or becomes symptomatic 4
• Reassure parents and provide anticipatory guidance to monitor for recurrence, returning only if hematuria persists or concerning symptoms develop 4

Isolated Macroscopic (Gross) Hematuria:

Ultrasound of the kidneys and bladder is the initial imaging modality of choice, as it effectively displays kidney anatomy, screens for structural lesions, and requires no ionizing radiation. 1, 5

• Ultrasound has a definite role in investigating suspected upper gastrointestinal and renal disease in children 6
• Plain radiography may be performed concurrently to detect calcifications and radiopaque stones 5

Painful Hematuria (Suspected Urolithiasis):

Ultrasound of the kidneys and bladder is the first-line imaging, though it has limited sensitivity for ureteral stones (38% detection rate). 1

• CT may be particularly useful in painful hematuria with negative kidney and bladder ultrasound and high clinical suspicion for urolithiasis, especially if detection would impact treatment 1
• CT has sensitivity and specificity both well above 90% for stone detection in adults, with proper low-dose techniques reducing radiation to less than traditional IVU 1
• Many pediatric patients with urolithiasis do not have hematuria, so absence of hematuria does not exclude stones 1

Hematuria with Palpable Abdominal Mass:

This presentation requires urgent ultrasound evaluation, as it raises concern for Wilms tumor or other renal masses, fundamentally changing the clinical scenario from isolated hematuria. 5, 6

• Ultrasound is critical for confirming renal origin of the mass, assessing the contralateral kidney (5-10% bilateral Wilms tumor involvement), evaluating for inferior vena cava involvement, and determining tumor size and extent 5, 6
• 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 5
• Delaying imaging by assuming isolated hematuria requires no workup is a critical pitfall when an abdominal mass is present 5

Traumatic Hematuria:

Macroscopic (gross) hematuria following trauma necessitates radiologic evaluation with contrast-enhanced CT of the abdomen and pelvis. 1

• All CT scans must be performed with intravenous contrast unless specifically contraindicated 1
• Isolated microscopic hematuria without clinical or laboratory findings of visceral trauma or concerning mechanism does not need emergency investigation 1
• Radiologic evaluation for renal injury is indicated when ≥50 red blood cells are present on urinalysis, when the patient is hypotensive on presentation, or based on mechanism of injury 1
• Blood in the urethral meatus with pelvic fractures should prompt investigation of the urethra and bladder (50% incidence of genitourinary injury) 1
• Minor trauma to an anomalous kidney can cause major clinical repercussions, as renal anomalies occur in 1-4% of the population 1

Nephrology Referral Indications

Prompt referral to pediatric nephrology is indicated when:

• Hematuria does not resolve within 2 weeks of onset of glomerulonephritis 2
• Renal biopsy is needed 2
• Persistent microscopic hematuria is present 2
• Specific urine biochemistry testing or advanced imaging studies are required 2
• Combination of hematuria and proteinuria exists (except clear post-streptococcal glomerulonephritis) 3

Critical Pitfalls to Avoid

• Advanced imaging modalities such as CT, MRI, or VCUG are not appropriate for isolated, transient microscopic hematuria in an otherwise well child and expose the child to unnecessary risk 4
• Isolated microscopic hematuria is very rarely the presenting scenario of Wilms tumor; brief, self-limited findings should not trigger oncologic concerns 4
• Hypotension is an unreliable clinical indicator for prompting imaging in children with trauma 1
• IVU is seldom indicated in children as an initial examination 1
• Proceeding directly to CT without ultrasound confirmation of renal origin in cases with abdominal mass is inappropriate, as ultrasound may reveal the mass is not renal in origin 5