Initial Management of a 4-Year-Old with Abdominal Pain and Abnormal Urinalysis
This child requires immediate urinalysis with microscopy to assess for glomerulonephritis, followed by basic metabolic panel and blood pressure measurement to evaluate for acute kidney disease, with specific attention to ruling out post-infectious glomerulonephritis or Henoch-Schönlein purpura (HSP). 1
Immediate Diagnostic Workup
The combination of abdominal pain, hazy urine, trace blood, and moderate proteinuria in a 4-year-old raises concern for glomerular disease rather than simple urinary tract infection.
Essential Initial Tests
- Urinalysis with microscopy is mandatory to look for red blood cell casts and dysmorphic red blood cells, which indicate glomerular involvement 1
- Basic metabolic panel including BUN and serum creatinine to assess renal function 1
- Complete blood count with platelets to rule out thrombocytopenia and assess for systemic disease 1
- Blood pressure measurement is essential, as hypertension may indicate more severe renal involvement 1
- Spot urine protein-to-creatinine ratio from first morning void is the practical alternative to 24-hour collection in children (normal ratio <0.2 g/g) 2, 3
Critical Clinical Assessment
Examine the child carefully for:
- Palpable purpura on lower extremities and buttocks, which combined with abdominal pain and hematuria forms the diagnostic triad for HSP 1
- Joint pain or swelling, particularly ankles 1
- Edema suggesting nephrotic syndrome 2
- Hypertension indicating significant renal involvement 1
Differential Diagnosis Priority
Most Likely: Henoch-Schönlein Purpura Nephritis
The clinical presentation of abdominal pain with hematuria and proteinuria in a 4-year-old is highly suggestive of HSP, which can be diagnosed clinically when palpable purpura is present plus at least one of: renal involvement (hematuria/proteinuria), arthralgia/arthritis, or abdominal pain 1. The triad of hematuria, purpuric lesions, and ankle pain is diagnostic 1.
Alternative Considerations
- Post-infectious glomerulonephritis if recent streptococcal infection 3
- IgA nephropathy (though less common in this age group) 2
- Urinary tract infection is less likely given moderate proteinuria and trace blood without significant leukocyte esterase 2
Management Algorithm
If HSP is Confirmed:
- Monitor renal function closely - persistent hematuria and proteinuria indicate ongoing disease activity 1
- Renal ultrasound if considering biopsy for severe nephritis 1
- For persistent proteinuria >1 g/day per 1.73 m² after trial of ACE inhibitor/ARB and GFR >50 ml/min per 1.73 m², consider 6-month corticosteroid course 1
- Avoid NSAIDs (including ketorolac/Toradol) due to risk of acute kidney injury in patients with renal impairment; use acetaminophen for pain control instead 1
If Glomerulonephritis Without HSP Features:
Referral to pediatric nephrology is warranted for persistent significant proteinuria (≥1+ on dipstick for 3 specimens), persistent microscopic hematuria, hypertension, or elevated BUN/creatinine 2.
Common Pitfalls to Avoid
- Do not dismiss trace ketones in a child with abdominal pain - while trace ketones can occur with poor oral intake, the combination with proteinuria and hematuria suggests primary renal pathology rather than simple dehydration 2
- Do not treat empirically as UTI without microscopy - the moderate proteinuria is disproportionate for simple cystitis and suggests glomerular disease 3, 4
- Do not delay nephrology referral if active urinary sediments, hypertension, or signs of renal insufficiency are present 3
- Avoid 24-hour urine collection in young children - spot protein-to-creatinine ratio is reliable and practical 2, 3
Monitoring Protocol
If initial workup suggests glomerular disease, the child requires: