What is the management approach for a teenager presenting with hematuria (blood in urine) and proteinuria (excess protein in urine)?

Management of Hematuria with Proteinuria in a Teenager

A teenager presenting with both hematuria and proteinuria requires immediate nephrology referral, as this combination strongly suggests glomerular disease that warrants specialized evaluation and likely renal biopsy. 1, 2

Initial Diagnostic Confirmation

Before proceeding with extensive workup, confirm true pathology:

• Verify microscopic hematuria with ≥3 RBCs per high-power field on at least two of three properly collected clean-catch midstream urine specimens 2, 3
• Quantify proteinuria using spot urine protein-to-creatinine ratio (normal <0.2 g/g in children; significant if >0.2 g/g on three specimens) 4, 1
• Exclude transient causes: Recent vigorous exercise within 24 hours, menstrual contamination in females, fever, or active urinary tract infection can cause false positives 2, 5

Critical Urinalysis with Microscopy

The urinary sediment examination is essential for determining glomerular versus non-glomerular origin:

• Examine for dysmorphic RBCs: >80% dysmorphic red blood cells indicates glomerular bleeding 2, 3
• Look for red cell casts: These are pathognomonic for glomerulonephritis 1, 2
• Assess proteinuria severity: Protein-to-creatinine ratio >1000 mg/g (>1 g/day) requires nephrology evaluation 1, 2

The presence of both proteinuria and hematuria strongly suggests a glomerular origin, particularly when dysmorphic RBCs or red cell casts are present. 2, 6

Essential Laboratory Workup

Obtain the following tests before nephrology referral:

• Complete metabolic panel including serum creatinine, BUN, albumin, and total protein to assess renal function and nephrotic syndrome 4, 3
• Complement levels (C3, C4) to evaluate for post-infectious glomerulonephritis or lupus nephritis 4, 3
• Antinuclear antibody (ANA) if systemic disease suspected 4
• Complete blood count to evaluate for systemic disease 3

Imaging Considerations

Renal ultrasound is the appropriate first-line imaging modality in teenagers with hematuria and proteinuria to evaluate kidney size, echogenicity, and structural abnormalities:

• Enlarged echogenic kidneys suggest acute glomerulonephritis 4, 3
• Ultrasound can identify anatomic abnormalities, though yield is low in isolated microscopic hematuria 4
• CT and MRI are NOT appropriate in the initial evaluation of hematuria with proteinuria in children 4
• VCUG, IVU, and arteriography are NOT indicated for this presentation 4

Immediate Nephrology Referral Criteria

Refer urgently to pediatric nephrology if ANY of the following are present:

• Persistent significant proteinuria (protein-to-creatinine ratio >0.2 g/g on three specimens) 4, 1
• Red cell casts or >80% dysmorphic RBCs suggesting glomerulonephritis 4, 1, 2
• Elevated serum creatinine or declining renal function 4, 7
• Hypertension accompanying hematuria and proteinuria 4, 7
• Gross hematuria with proteinuria 4
• Active urinary sediment with signs of glomerular disease 7, 8

Common Pitfalls to Avoid

Do not delay nephrology referral while pursuing urologic evaluation—the combination of hematuria and proteinuria in a teenager is glomerular disease until proven otherwise 2, 6

Do not attribute findings to benign causes without proper evaluation: While orthostatic proteinuria is common in adolescents, it should not be accompanied by hematuria 6, 9

Do not perform cystoscopy or extensive urologic imaging as the initial approach when glomerular features are present—this delays appropriate diagnosis and treatment 4, 2

Do not wait for symptoms to develop: Persistent proteinuria with hematuria may indicate chronic kidney disease even in asymptomatic teenagers and requires prompt evaluation 6, 9

Likely Differential Diagnoses in Teenagers

The most common glomerular causes in this age group include:

• IgA nephropathy: Most common cause of glomerulonephritis in adolescents, presenting with episodic gross hematuria and persistent microscopic hematuria with proteinuria 3, 5
• Post-infectious glomerulonephritis: Follows streptococcal infection, associated with low C3 levels 3, 5
• Alport syndrome: Hereditary nephritis with hearing loss and ocular abnormalities, consider if family history present 3, 5
• Lupus nephritis: Consider in females with systemic symptoms 4

Renal biopsy will likely be necessary for definitive diagnosis and to guide prognosis and therapy in persistent cases 4, 8