What is the treatment for a yeast infection in the urinary tract indicated by urinalysis?

Treatment for Yeast Infections in the Urinary Tract

For symptomatic Candida urinary tract infections, oral fluconazole at a dosage of 200 mg daily for 2 weeks is the recommended first-line treatment for fluconazole-susceptible organisms. 1

Diagnostic Approach

Before initiating treatment, it's important to distinguish between colonization and true infection:

• Presence of yeast in urine must be evaluated in clinical context
• Colony count alone cannot define infection, especially with indwelling catheters
• Symptoms of UTI (dysuria, frequency, urgency) help distinguish infection from colonization
• Imaging (ultrasound or CT) may be helpful to identify structural abnormalities or fungus balls

Treatment Algorithm

1. Asymptomatic Candiduria

• No treatment recommended unless patient belongs to high-risk group 1
• Remove predisposing factors (indwelling catheters, antibiotics) which often resolves candiduria in ~50% of cases 2
• High-risk patients requiring treatment despite being asymptomatic include:
  • Neutropenic patients
  • Low birth weight infants
  • Patients undergoing urologic procedures

2. Symptomatic Candida Cystitis (Lower UTI)

• First-line: Fluconazole 200 mg (3 mg/kg) daily for 2 weeks 1
• For fluconazole-resistant organisms (especially C. glabrata):
  • AmB-d 0.3-0.6 mg/kg daily for 1-7 days, OR
  • Oral flucytosine 25 mg/kg 4 times daily for 7-10 days 1
• AmB-d bladder irrigation (50 mg/L sterile water daily for 5 days) may be useful for resistant strains but generally not recommended 1

3. Candida Pyelonephritis (Upper UTI)

• First-line: Fluconazole 200-400 mg (3-6 mg/kg) daily for 2 weeks 1
• For fluconazole-resistant organisms:
  • AmB-d 0.5-0.7 mg/kg daily with or without flucytosine 25 mg/kg 4 times daily for 2 weeks, OR
  • Flucytosine alone 25 mg/kg 4 times daily for 2 weeks 1
• Eliminate any urinary tract obstruction 1

4. Fungus Balls

• Surgical intervention strongly recommended in non-neonates 1
• Fluconazole 200-400 mg daily until resolution 1
• Consider irrigation with AmB-d (50 mg/L sterile water) if access to collecting system is available 1

Antifungal Selection Considerations

Fluconazole is the preferred agent because:

• Achieves high urine concentrations in active form 1
• Available in both oral and IV formulations 3
• Well-tolerated safety profile 4

Other antifungals have limitations:

• Echinocandins and most other azoles achieve minimal urine concentrations 1
• Amphotericin B requires IV administration and has significant toxicity 1
• Lipid formulations of AmB don't achieve adequate urine concentrations 1
• Flucytosine has good activity but limited by toxicity and resistance development when used alone 1

Common Pitfalls to Avoid

1. Treating asymptomatic candiduria in low-risk patients - unnecessary and may promote resistance 1

2. Using echinocandins or newer azoles for urinary tract infections - these agents don't achieve adequate urine concentrations 2, 4

3. Not removing indwelling catheters - catheter removal alone resolves many cases of candiduria 5

4. Failure to identify and correct underlying risk factors - diabetes management, reducing antibiotic use 5

5. Not distinguishing between lower and upper tract infection - treatment duration and dosing may differ 1

6. Using lipid formulations of amphotericin B for UTI - these don't achieve adequate urine concentrations 1

Remember that treatment decisions should be guided by the patient's symptoms, the location of infection, and the susceptibility of the Candida species involved.