What is the appropriate management for a 10-year-old male with leg pain, vomiting, hematuria, ketonuria, and proteinuria?

Immediate Management for 10-Year-Old with Leg Pain, Vomiting, and Abnormal Urinalysis

This child requires urgent evaluation for post-infectious glomerulonephritis or IgA nephropathy, with immediate laboratory workup including complete metabolic panel, serum creatinine, BUN, complement levels (C3, C4), and antistreptolysin O titer, followed by renal ultrasound and prompt pediatric nephrology referral. 1

Critical Initial Assessment

The combination of leg pain (likely arthralgias), vomiting, hematuria, and proteinuria in a 10-year-old strongly suggests glomerular disease rather than isolated benign hematuria. 1 The presence of both hematuria AND proteinuria together is a red flag that mandates aggressive evaluation, as this combination indicates potential glomerulonephritis. 2, 3

Key immediate actions:

• Obtain blood pressure measurement immediately - hypertension is a critical indicator of glomerular disease severity and requires urgent management 1
• Assess for edema - periorbital or peripheral edema suggests nephrotic-range proteinuria or acute glomerulonephritis 1
• Evaluate hydration status - vomiting with potential renal involvement creates risk for acute kidney injury 1

Essential Laboratory Workup

Immediate blood tests required:

• Complete metabolic panel including total protein and albumin levels to assess for hypoalbuminemia 1
• Serum creatinine and BUN to evaluate renal function - critical for detecting acute kidney injury 1
• Complement levels (C3, C4) - low C3 suggests post-infectious glomerulonephritis 1
• Antinuclear antibody testing to evaluate for systemic lupus erythematosus 1
• Antistreptolysin O titer if post-streptococcal glomerulonephritis suspected 1
• Complete blood count to assess for anemia or thrombocytopenia 2

Urine studies needed:

• Urinary protein-to-creatinine ratio - normal is <0.2 g/g; values >0.2 indicate significant proteinuria requiring nephrology referral 1
• Microscopic urinalysis specifically looking for dysmorphic red blood cells and red cell casts, which confirm glomerular origin 2, 3
• Urine culture to rule out urinary tract infection 2

Imaging Requirements

Renal ultrasound is indicated immediately given the combination of hematuria, proteinuria, and systemic symptoms. 1 The ultrasound should assess:

• Kidney size and echogenicity - enlarged echogenic kidneys suggest acute glomerulonephritis 1
• Structural abnormalities or masses - though rare, Wilms tumor can present with hematuria 1, 4
• Corticomedullary differentiation 1

CT imaging is NOT appropriate for initial evaluation of this presentation. 1, 2

Mandatory Nephrology Referral Criteria

This patient meets multiple criteria for urgent pediatric nephrology referral: 1

• Presence of both proteinuria (1+) AND hematuria together
• Systemic symptoms (leg pain, vomiting) suggesting possible systemic disease
• Potential acute glomerulonephritis based on clinical presentation

The guidelines explicitly state that referral is warranted for "persistent significant proteinuria (grade 1+ by urine dipstick analysis or protein-to-creatinine ratio >0.2 for 3 specimens), persistent microscopic hematuria, gross hematuria in the absence of urinary tract infection." 1 This child's presentation is more concerning than isolated findings.

Differential Diagnosis Priority

Most likely diagnoses to consider:

• Post-infectious glomerulonephritis - most common cause of acute glomerulonephritis in children, often presents with hematuria, proteinuria, edema, hypertension, and systemic symptoms 1
• IgA nephropathy (Berger disease) - common cause of glomerular hematuria in children, can present with gross hematuria following upper respiratory infection 1, 2
• Henoch-Schönlein purpura - would explain leg pain (arthralgia), vomiting (abdominal pain), and glomerulonephritis 1

Less likely but must exclude:

• Hemolytic uremic syndrome - though typically presents with more severe symptoms 1
• Systemic lupus erythematosus - requires ANA testing 1

Critical Pitfalls to Avoid

• Do NOT dismiss this as benign isolated microscopic hematuria - the combination with proteinuria and systemic symptoms indicates glomerular disease 2, 3
• Do NOT delay nephrology referral - waiting for "persistent" findings over weeks is inappropriate when proteinuria and hematuria coexist with systemic symptoms 1
• Do NOT assume ketones are solely from vomiting - while small ketones may be from poor oral intake, the complete clinical picture requires full evaluation 1
• Do NOT order extensive imaging before basic labs - blood work and urinalysis guide subsequent management 2

Supportive Management Pending Workup

• Ensure adequate hydration - IV fluids may be needed given vomiting 1
• Monitor urine output closely - oliguria would indicate more severe renal involvement 1
• Avoid nephrotoxic medications - no NSAIDs for pain control 5
• Blood pressure control if elevated - hypertension in acute glomerulonephritis requires prompt treatment 1