How should a 7-year-old child presenting with facial edema, fever, and a urinalysis showing 30–60 white blood cells per high‑power field and +2 protein be evaluated and managed?

Acute Post-Streptococcal Glomerulonephritis (PSGN) – Immediate Evaluation and Management

This 7-year-old with facial edema, fever, and urinalysis showing 30–60 WBC/HPF with +2 proteinuria most likely has acute post-streptococcal glomerulonephritis (PSGN), not a urinary tract infection. The combination of facial edema (periorbital swelling), significant proteinuria, and marked pyuria without bacteriuria is the classic triad of acute glomerulonephritis, and you must immediately evaluate for this diagnosis rather than treating empirically for UTI.

Why This Is NOT a Typical UTI

• The urinalysis pattern is wrong for UTI: While 30–60 WBC/HPF represents marked pyuria, the presence of +2 proteinuria (100–300 mg/dL) is not typical of uncomplicated UTI, where proteinuria is usually absent or trace 1.
• Facial edema is a red flag: Periorbital or facial edema in a febrile child with abnormal urinalysis strongly suggests glomerulonephritis, not pyelonephritis 1.
• Age and presentation: At 7 years old, this child is in the peak age range (6–10 years) for PSGN, which typically presents 1–3 weeks after a streptococcal pharyngitis or skin infection 1.

Immediate Diagnostic Workup

Before starting any antibiotics, obtain the following studies to confirm or exclude glomerulonephritis:

• Urine culture via catheterization or clean-catch midstream specimen to definitively rule out UTI (diagnosis requires ≥50,000 CFU/mL of a single uropathogen plus pyuria) 1, 2.
• Complete urinalysis with microscopy looking specifically for:
  • Red blood cell casts (pathognomonic for glomerulonephritis)
  • Dysmorphic RBCs (>80% suggests glomerular origin)
  • Degree of proteinuria (quantify with urine protein-to-creatinine ratio if +2 or greater) 1.
• Serum studies:
  • Serum creatinine and BUN (assess renal function)
  • Serum complement C3 and C4 (low C3 with normal C4 is classic for PSGN)
  • Anti-streptolysin O (ASO) titer and anti-DNase B (evidence of recent streptococcal infection)
  • Complete blood count (assess for anemia from hemolysis or dilution)
  • Serum electrolytes (check for hyperkalemia, hyponatremia) 1.
• Blood pressure measurement (hypertension is present in 60–80% of PSGN cases and requires immediate management if severe) 1.

Critical Clinical Decision Point

If the urine culture is negative or shows <50,000 CFU/mL and the child has:

• Red blood cell casts or dysmorphic RBCs on microscopy
• Low serum C3 level
• Elevated ASO or anti-DNase B titers
• Hypertension or significant edema

→ This is acute glomerulonephritis, NOT UTI, and requires nephrology consultation within 24 hours 1.

If UTI Is Confirmed (Culture ≥50,000 CFU/mL)

Only if the urine culture grows ≥50,000 CFU/mL of a single uropathogen should you proceed with UTI management:

• Start empiric oral antibiotics immediately after obtaining culture:
  • First-line: Amoxicillin-clavulanate 40–45 mg/kg/day divided BID, OR
  • Cefixime 8 mg/kg once daily, OR
  • Cephalexin 50–100 mg/kg/day divided QID 1, 3, 2.
• Treatment duration: 7–14 days (10 days most common) for febrile UTI 1, 3, 2.
• Adjust antibiotics based on culture and sensitivity results when available 1, 3, 2.

Imaging Recommendations

For a 7-year-old with first UTI:

• Renal and bladder ultrasound is NOT routinely indicated for children >2 years with a first uncomplicated UTI 1, 2.
• Obtain ultrasound only if:
  • Fever persists >48 hours on appropriate antibiotics
  • Non-E. coli organism is cultured
  • Elevated serum creatinine
  • Septic or seriously ill appearance
  • Poor urine flow or abdominal mass 3, 2.
• VCUG is NOT indicated after a first UTI regardless of fever status 1, 2.

Follow-Up Strategy

• Clinical reassessment within 24–48 hours to confirm fever resolution and clinical improvement 1, 3, 2.
• No routine follow-up urine culture is needed after successful treatment 3, 2.
• Instruct parents to seek prompt evaluation (within 48 hours) for any future febrile illness to detect recurrent UTI early 1, 3, 2.

Common Pitfalls to Avoid

• Do NOT assume this is UTI based on pyuria alone—the combination of facial edema, fever, and significant proteinuria mandates evaluation for glomerulonephritis 1.
• Do NOT start antibiotics before obtaining urine culture—this is your only opportunity for definitive diagnosis 1, 3, 2.
• Do NOT use nitrofurantoin if this turns out to be febrile UTI, as it does not achieve adequate serum/parenchymal concentrations for pyelonephritis 1, 3, 2.
• Do NOT treat for <7 days if febrile UTI is confirmed, as shorter courses are inferior 1, 3, 2.
• Do NOT order routine imaging for a 7-year-old with first uncomplicated UTI—this increases unnecessary costs and radiation exposure without benefit 1, 2.

When to Refer to Nephrology

Immediate nephrology consultation is indicated if:

• Red blood cell casts or dysmorphic RBCs are present on microscopy
• Serum creatinine is elevated
• Severe hypertension (>95th percentile for age/height)
• Significant edema requiring diuretic therapy
• Low C3 complement level
• Oliguria or signs of fluid overload 1.