What is the appropriate management for a 14-year-old patient with microscopic hematuria (5-10 Red Blood Cells (RBC) per high power field (hpf)) in the urine, suggestive of a urinary tract infection (UTI)?

Management of Microscopic Hematuria (5-10 RBC/hpf) in a 14-Year-Old Patient

In a 14-year-old with 5-10 RBC/hpf and clinical suspicion of UTI (presence of white blood cells, bacteria, or urinary symptoms), treat the infection first with appropriate antibiotics and repeat urinalysis 6 weeks after treatment completion—if hematuria resolves, no further workup is needed. 1

Initial Diagnostic Approach

Confirm True Hematuria and Assess for Infection

• Verify microscopic hematuria with properly collected clean-catch midstream urine specimen showing ≥3 RBCs/hpf (5-10 RBC/hpf meets this threshold) 2
• Examine the complete urinalysis for white blood cells, bacteria, leukocyte esterase, and nitrites to identify UTI as the likely cause 1
• Obtain urine culture before initiating antibiotics to confirm infection and guide antibiotic selection 1
• Assess for proteinuria using dipstick (≥2+ suggests glomerular disease requiring different evaluation pathway) 2

Key Clinical Features to Elicit

• Urinary symptoms: dysuria, frequency, urgency, suprapubic pain (suggest UTI) 1
• Flank pain or costovertebral angle tenderness (suggest pyelonephritis or nephrolithiasis) 2
• Recent pharyngitis or skin infection (suggest post-infectious glomerulonephritis) 2
• Family history of kidney disease, hearing loss, or hematuria (suggest hereditary nephropathy like Alport syndrome or thin basement membrane disease) 2
• Recent trauma (even minor trauma in children can cause hematuria due to anatomical vulnerability) 2

Management Algorithm Based on Clinical Presentation

If UTI is Present (Most Likely Scenario)

Treat the infection and reassess:

• Initiate appropriate antibiotic therapy based on local resistance patterns—first-line options include trimethoprim-sulfamethoxazole, amoxicillin-clavulanate, nitrofurantoin, or cephalexin 3, 4
• Repeat urinalysis 6 weeks after completing antibiotics to document resolution of hematuria 1
• If hematuria resolves with treatment, no additional evaluation is necessary 1
• If hematuria persists after successful UTI treatment, proceed with complete evaluation as outlined below 1

If No UTI is Present (Isolated Microscopic Hematuria)

In children with isolated microscopic hematuria without proteinuria or dysmorphic RBCs, no imaging is indicated initially:

• No imaging is recommended for asymptomatic microscopic hematuria without proteinuria in children, as clinically significant renal disease is unlikely 2
• Clinical observation with repeat urinalysis on 2-3 consecutive specimens to confirm persistence 2
• Screen family members' urine for benign familial hematuria or thin basement membrane nephropathy 2
• Evaluate for hypercalciuria with spot urine calcium-to-creatinine ratio, as this is a common benign cause in children 2

Red Flags Requiring Immediate Further Evaluation

Proceed directly to imaging and nephrology referral if any of the following are present:

• Proteinuria ≥2+ on dipstick (suggests glomerular disease) 2
• Dysmorphic RBCs or red blood cell casts on microscopy (pathognomonic for glomerulonephritis) 2, 5
• Tea-colored or cola-colored urine (suggests glomerular bleeding) 2, 5
• Hypertension, edema, or elevated creatinine (suggests renal parenchymal disease) 2
• Macroscopic (gross) hematuria (requires ultrasound to exclude tumors, stones, or structural abnormalities) 2

Pediatric-Specific Considerations

Why Children Are Different

• Microscopic hematuria <50 RBC/hpf is common in children (1-36% prevalence) due to kidney anatomy and undiagnosed kidney diseases 2
• The threshold for imaging in trauma is >50 RBC/hpf in children, unlike adults where lower thresholds apply 2
• Isolated microscopic hematuria in children is usually benign and often resolves spontaneously 2
• Glomerulonephritis (especially post-infectious and IgA nephropathy) is more common than malignancy in pediatric hematuria 2

Age-Appropriate Imaging When Indicated

• Ultrasound is the preferred initial imaging modality in children to assess kidney size, echogenicity, structural abnormalities, and bladder lesions 2
• CT is not appropriate for initial evaluation of isolated nonpainful, nontraumatic hematuria in children due to radiation exposure 2
• Ultrasound should include bladder evaluation when distended with urine to assess for polyps, masses, or vascular lesions 2

Common Pitfalls to Avoid

• Do not attribute hematuria to "normal variation" without proper evaluation—while <50 RBC/hpf may not require imaging in trauma, 5-10 RBC/hpf with UTI symptoms requires treatment and follow-up 2, 1
• Do not perform extensive imaging workup before treating obvious UTI—treat infection first and reassess 1
• Do not ignore persistent hematuria after UTI treatment—this requires complete urologic evaluation 1
• Do not overlook proteinuria—even trace proteinuria with hematuria warrants nephrology evaluation 2
• Do not dismiss family history—benign familial hematuria and thin basement membrane nephropathy are autosomal dominant and common causes of persistent microscopic hematuria in children 2