What is the diagnosis and treatment for a 15-year-old female patient with hematuria (blood in urine), proteinuria (protein in urine), a positive nitrate test, leukocyturia (leukocytes in urine), and leukocytosis (elevated white blood cell count) of 15.9?

Diagnosis: Acute Urinary Tract Infection with Possible Glomerular Component

This 15-year-old female has a urinary tract infection that requires immediate antibiotic treatment after obtaining a urine culture, with close monitoring for potential glomerular disease given the combination of hematuria and proteinuria. 1, 2

Immediate Diagnostic Interpretation

The urinalysis findings indicate:

• Positive nitrites with leukocyturia (1+ leukocytes) strongly suggests bacterial UTI, as nitrites have 98% specificity for infection despite only 49% sensitivity 1
• The elevated WBC count of 15.9 supports systemic inflammatory response to infection 1
• The combination of 1+ blood and 1+ protein raises concern for potential glomerular involvement, which can occur with post-infectious glomerulonephritis or concurrent renal parenchymal disease 2, 1

Critical Next Steps Before Treatment

Obtain urine culture immediately before starting antibiotics to identify the causative organism and guide antibiotic selection, as culture is the gold standard for UTI diagnosis 1, 3

Confirm microscopic hematuria with ≥3 RBCs per high-power field on microscopic examination, as dipstick testing has only 65-99% specificity and can produce false positives 2

Examine urinary sediment for:

• Dysmorphic RBCs (>80% suggests glomerular disease) 2
• Red blood cell casts (pathognomonic for glomerulonephritis) 2
• WBC casts (suggest pyelonephritis or interstitial nephritis) 1

Essential Laboratory Evaluation

Obtain the following labs to distinguish UTI from glomerular disease:

• Quantify proteinuria using spot urine protein-to-creatinine ratio (normal <0.2 g/g; significant proteinuria ≥0.2 suggests renal parenchymal disease) 1, 2
• Complete metabolic panel including serum creatinine, BUN, albumin, and total protein to assess renal function 1, 2
• Complement levels (C3, C4) if glomerulonephritis suspected, particularly with recent viral illness 1, 2

Antibiotic Treatment Protocol

Start empiric antibiotic therapy immediately after obtaining urine culture:

• First-line options include nitrofurantoin, trimethoprim-sulfamethoxazole, or cephalexin based on local resistance patterns 1
• Do not delay treatment waiting for culture results in symptomatic patients with positive nitrites and leukocyturia 1, 3
• Adjust antibiotics based on culture sensitivities when available 1

Nephrology Referral Criteria

Refer to pediatric nephrology if any of the following develop:

• Persistent significant proteinuria (protein-to-creatinine ratio ≥0.2 for three specimens) 1, 2
• Presence of red blood cell casts or >80% dysmorphic RBCs indicating glomerular disease 2
• Elevated creatinine or declining renal function 2
• Persistent hematuria after UTI treatment (hematuria should resolve with successful UTI treatment if purely infectious) 2
• Development of hypertension, edema, or nephrotic-range proteinuria 1, 4

Follow-Up Monitoring

Repeat urinalysis 1-2 weeks after completing antibiotics to confirm resolution of pyuria and bacteriuria 2

If hematuria and proteinuria persist after UTI resolution:

• This suggests underlying glomerular disease requiring renal biopsy consideration 1, 2
• Post-infectious glomerulonephritis can present 1-3 weeks after infection with persistent hematuria, proteinuria, and low complement levels 1, 2

Critical Pitfalls to Avoid

Never attribute hematuria solely to UTI without confirming resolution after treatment, as concurrent glomerular disease can be masked by infection 2

Do not dismiss the proteinuria as insignificant—the combination of blood and protein in a 15-year-old warrants careful follow-up even if UTI is confirmed 1, 2

Ensure proper urine collection technique (clean-catch midstream) to avoid contamination that could confound results, particularly in adolescent females 1, 2