What is the recommended treatment approach for a patient with Candida pyelonephritis, particularly one with a compromised immune system and a history of urinary tract infections, according to the Infectious Diseases Society of America (IDSA) guidelines?

IDSA Guidelines for Candida Pyelonephritis

First-Line Treatment

For fluconazole-susceptible Candida species, treat with oral fluconazole 200-400 mg (3-6 mg/kg) daily for 2 weeks. 1

This represents the cornerstone of therapy for most patients with Candida pyelonephritis, including those with compromised immune systems, as fluconazole achieves excellent urinary concentrations and has a strong safety profile. 1, 2

Treatment Algorithm Based on Species and Susceptibility

Fluconazole-Susceptible Species

• Oral fluconazole 200-400 mg (3-6 mg/kg) daily for 2 weeks is the recommended regimen (strong recommendation). 1
• This applies to most Candida albicans and susceptible non-albicans species. 3

Fluconazole-Resistant C. glabrata

• Amphotericin B deoxycholate 0.3-0.6 mg/kg daily for 1-7 days with or without oral flucytosine 25 mg/kg 4 times daily (strong recommendation). 1
• Alternative: Flucytosine monotherapy 25 mg/kg 4 times daily for 2 weeks can be considered (weak recommendation). 1

C. krusei

• Amphotericin B deoxycholate 0.3-0.6 mg/kg daily for 1-7 days (strong recommendation). 1
• C. krusei is intrinsically resistant to fluconazole, making amphotericin B the necessary choice. 3

Critical Adjunctive Measures

Urinary Tract Obstruction

• Elimination of urinary tract obstruction is strongly recommended (strong recommendation). 1
• This is essential for treatment success and preventing treatment failure. 1

Nephrostomy Tubes and Stents

• Consider removal or replacement of nephrostomy tubes or stents if feasible (weak recommendation). 1
• If tubes remain in place, irrigation with amphotericin B deoxycholate 25-50 mg in 200-500 mL sterile water is recommended for fungus balls. 1

Indwelling Catheters

• Remove indwelling bladder catheters whenever feasible (strong recommendation). 1
• Catheter removal alone resolves candiduria in approximately 50% of cases. 3, 4

Special Populations

Neutropenic Patients

• Treat as recommended for candidemia rather than isolated pyelonephritis (strong recommendation). 1
• These patients are at high risk for dissemination and require more aggressive therapy. 1

Patients Undergoing Urologic Procedures

• Prophylactic fluconazole 400 mg (6 mg/kg) daily OR amphotericin B deoxycholate 0.3-0.6 mg/kg daily for several days before and after the procedure (strong recommendation). 1, 5

Hemodialysis Patients

• Fluconazole 200-400 mg daily for 2 weeks remains first-line for susceptible species. 5
• Use amphotericin B formulations with caution due to potential nephrotoxicity in this population. 5

Important Caveats and Pitfalls

Echinocandins Are Not Recommended

• Echinocandins (caspofungin, micafungin, anidulafungin) do not achieve adequate urinary concentrations and should not be used for isolated urinary tract infections. 2, 4, 6
• They may have a role only in disseminated candidiasis with renal involvement. 6

Newer Azoles Have Limited Utility

• Voriconazole and posaconazole do not achieve sufficient urine levels for primary treatment of Candida pyelonephritis. 2, 4

Asymptomatic Candiduria

• Treatment is NOT recommended for asymptomatic candiduria unless the patient is neutropenic, a very low-birth-weight infant (<1500 g), or undergoing urologic manipulation (strong recommendation). 1, 5

Fungus Balls

• Surgical intervention is strongly recommended in adults with fungus balls (strong recommendation). 1
• Combine with antifungal therapy as outlined above for cystitis or pyelonephritis. 1