What is the best treatment approach for a patient with a history of complex medical conditions, including an ileostomy, and a current diagnosis of candidiasis (fungal infection) in their urine culture, who may have impaired renal function and is immunocompromised?

Treatment of Candiduria in a Complex Patient with Ileostomy and Immunocompromise

For this immunocompromised patient with candiduria, antifungal treatment is indicated, and oral fluconazole 200 mg (3 mg/kg) daily for 14 days is the first-line therapy, with dose adjustment needed if renal function is impaired. 1, 2

Initial Risk Stratification: Does This Patient Require Treatment?

Your patient requires treatment because they are immunocompromised, which places them in a high-risk category for disseminated candidiasis. 1, 2 The IDSA guidelines are explicit that treatment is NOT recommended for most patients with candiduria unless they fall into specific high-risk groups: neutropenic patients, very low-birth-weight infants (<1500g), or patients undergoing urologic procedures. 1, 2 However, immunocompromised patients with fever and candiduria should be treated due to concern for disseminated disease. 2

Critical Decision Point: Symptomatic vs Asymptomatic

• If your patient has fever with candiduria in the setting of severe immunocompromise, treat as candidemia (not just UTI) with an echinocandin, not fluconazole. 2
• If your patient has symptomatic cystitis or pyelonephritis without systemic signs, proceed with UTI-directed therapy below. 1
• The ileostomy itself does not change candiduria management, but may contribute to dehydration and altered renal function requiring dose adjustment. 1

Treatment Algorithm Based on Candida Species and Renal Function

For Fluconazole-Susceptible Species (C. albicans, C. tropicalis, C. parapsilosis)

First-line therapy: Oral fluconazole 200 mg (3 mg/kg) daily for 14 days for cystitis. 1, 2 For pyelonephritis, increase to fluconazole 200-400 mg (3-6 mg/kg) daily for 14 days. 1

• Fluconazole is preferred because it achieves high urinary concentrations in its active form, is available orally (critical for a patient with an ileostomy who can take oral medications), and has proven efficacy in the only randomized placebo-controlled trial for candiduria. 1, 3
• Renal dose adjustment: If creatinine clearance is impaired, reduce fluconazole dose by 50% after a standard loading dose. 1

For Fluconazole-Resistant C. glabrata

First-line therapy: Amphotericin B deoxycholate 0.3-0.6 mg/kg IV daily for 1-7 days. 1, 2

Alternative: Oral flucytosine 25 mg/kg four times daily for 7-10 days. 1, 2

• Flucytosine achieves excellent urinary concentrations but requires extreme caution in patients with renal impairment due to toxicity risk and must be dose-adjusted. 1, 3
• Weak recommendation: Flucytosine monotherapy for 2 weeks can be considered for C. glabrata cystitis, but this is based on low-quality evidence. 1

For C. krusei

Recommended therapy: Amphotericin B deoxycholate 0.3-0.6 mg/kg IV daily for 1-7 days. 1, 2

• C. krusei is intrinsically fluconazole-resistant, making amphotericin B the only reliable option. 1

Critical Management Steps Beyond Antifungals

Catheter Management

Remove any indwelling bladder catheter immediately if feasible. 1, 2 This is a strong recommendation because failure to remove catheters leads to treatment failure and relapse in the majority of cases. 2 Catheter removal alone clears candiduria in approximately 40% of patients. 1

Urinary Tract Obstruction

• Eliminate any urinary tract obstruction (strong recommendation). 1
• If nephrostomy tubes or ureteral stents are present, consider removal or replacement if feasible. 1
• For fungus balls causing obstruction, surgical or endoscopic removal is mandatory in addition to antifungal therapy. 2, 4

What NOT to Do: Common Pitfalls

Never Use These Agents for Candida UTI

Do not use echinocandins (caspofungin, micafungin, anidulafungin) or non-fluconazole azoles (voriconazole, posaconazole, isavuconazole) for Candida UTI because they do not achieve therapeutic urinary concentrations. 2, 3, 5 While there are isolated case reports of success with echinocandins for renal parenchymal infections (where tissue concentrations may be adequate), failures are common and these should not be first-line. 1, 3

Bladder Irrigation Has Limited Utility

Amphotericin B bladder irrigation (50 mg/L sterile water daily for 5 days) may be considered for fluconazole-resistant cystitis, but relapse rates exceed 80-90%. 1, 2 Reserve this only for refractory cases where systemic therapy has failed. 2

Special Considerations for Your Patient

Impaired Renal Function

• Fluconazole requires dose reduction by 50% if creatinine clearance is significantly impaired. 1
• Amphotericin B will worsen renal function—monitor creatinine and electrolytes closely, and never exceed 1.5 mg/kg total daily dose. 6
• Flucytosine is renally cleared and highly toxic in renal impairment—dose adjustment is mandatory. 1, 3

Ileostomy Considerations

• Oral fluconazole absorption should not be significantly affected by an ileostomy, as it is well-absorbed in the upper GI tract. 3
• Monitor for dehydration, which may worsen renal function and complicate dosing. 1

If Systemic Candidiasis is Suspected

If your patient has fever, hypotension, or other signs of systemic infection, do not treat this as a simple UTI. Treat as candidemia with an echinocandin (caspofungin 70 mg loading dose then 50 mg daily, micafungin 100 mg daily, or anidulafungin 200 mg loading dose then 100 mg daily) for at least 2 weeks after blood cultures clear. 1, 2