Diagnosis and Treatment of Pediatric Pyuria with Yeast Cells and Fever
Diagnosis
This 6-year-old male has candiduria (yeast in urine) with pyuria (20-30 WBC/hpf) and fever, most likely representing either urinary tract colonization with Candida or true fungal cystitis. The presence of moderate yeast cells with significant pyuria and fever requires verification and careful evaluation before initiating treatment 1, 2.
Immediate Diagnostic Steps
- Repeat the urinalysis and obtain a properly collected urine culture (clean-catch midstream or catheterized specimen) to verify candiduria and quantify colony counts 2
- The presence of pyuria (20-30 WBC/hpf) is nonspecific and does not definitively distinguish between colonization and true infection 2
- Candida albicans is the most commonly isolated species in funguria, though other Candida species may be present 3
- Colony counts have not proven diagnostically useful for distinguishing colonization from infection 2
Risk Assessment
Most pediatric patients with candiduria are colonized rather than infected and do not require antifungal therapy 1. However, this patient's fever warrants further evaluation:
- First, rule out bacterial urinary tract infection - the pyuria could indicate concurrent bacterial UTI, which is more common in this age group 4
- Consider whether predisposing factors are present: recent antibiotic use, indwelling catheter, diabetes mellitus, or immunocompromise 1, 3
- In the absence of symptoms or risk factors, removing predisposing factors (especially antibiotics) clears candiduria in almost 50% of asymptomatic patients 1
Additional Evaluation if Symptomatic
If the patient has dysuria, frequency, urgency, or suprapubic pain suggesting symptomatic cystitis:
- Obtain renal and bladder ultrasonography to evaluate for upper tract involvement, hydronephrosis, or fungal balls 2
- CT imaging is superior to ultrasound for detecting pyelonephritis or perinephric abscess if upper tract disease is suspected 2
Treatment
For Asymptomatic Candiduria (Colonization)
If the patient is afebrile after initial evaluation and has no urinary symptoms, no antifungal treatment is indicated 1. Instead:
- Remove or address predisposing factors (discontinue antibiotics if possible) 1, 3
- Repeat urine culture in 1-2 weeks to document clearance 1
For Symptomatic Candida Cystitis
If the patient has persistent fever with urinary symptoms and verified candiduria, treat with oral fluconazole 1, 3:
- Fluconazole is the antifungal agent of choice, achieving high urine concentrations with oral formulation 1
- Pediatric dosing: 6 mg/kg on day 1, then 3 mg/kg/day for 7-14 days 5
- Fluconazole is safe and effective in children aged 6 months to 13 years 5
Alternative Agents
- Amphotericin B deoxycholate is reserved for fluconazole-resistant species or severe infections 1, 3
- Flucytosine is rarely used 1
- Newer azoles and echinocandins are NOT recommended for urinary tract infections as they fail to achieve adequate urine concentrations 1
Critical Pitfall to Avoid
Do not assume this is a simple fungal UTI without first ruling out bacterial infection. In a 6-year-old with fever and significant pyuria:
- Bacterial UTI is far more common than symptomatic Candida cystitis in immunocompetent children 4
- The yeast cells may represent colonization while bacteria are the true pathogen
- If bacterial UTI is confirmed (≥50,000 CFU/mL of uropathogen), treat with appropriate antibiotics based on local sensitivity patterns for 7-14 days 4
- Consider amoxicillin-clavulanate or trimethoprim-sulfamethoxazole as first-line agents for bacterial UTI 4, 6
Treatment Algorithm
- Obtain properly collected urine culture immediately 2
- If bacterial pathogen grows ≥50,000 CFU/mL: treat as bacterial UTI 4
- If only Candida grows with persistent symptoms: treat with fluconazole 1
- If only Candida grows without symptoms: observe and remove predisposing factors 1
- Perform renal ultrasound if symptoms persist or worsen to rule out upper tract involvement 2