What are the typical signs, symptoms, and first‑line treatment of a Candida urinary tract infection in adults?

Signs of Urinary Tract Fungal Infection

For symptomatic Candida urinary tract infection, the key signs include dysuria, urinary frequency, urgency, and suprapubic discomfort for cystitis; flank pain and fever indicate pyelonephritis, and first-line treatment is oral fluconazole 200 mg daily for 14 days after removing any indwelling catheter. 1, 2

Clinical Presentation of Candida UTI

Lower Urinary Tract Infection (Cystitis)

• Dysuria (painful urination) is the hallmark symptom of Candida cystitis 3
• Urinary frequency and urgency occur commonly in symptomatic lower tract infection 3
• Suprapubic pain or discomfort may be present 1
• Hematuria can develop in some cases 1

Upper Urinary Tract Infection (Pyelonephritis)

• Flank pain and costovertebral angle tenderness indicate upper tract involvement 1, 2
• Fever (typically >38.3°C) suggests pyelonephritis rather than simple cystitis 2
• Systemic symptoms including chills, nausea, and vomiting may occur 1
• Altered mental status or malaise can develop, particularly in elderly or immunocompromised patients 1

Important Diagnostic Nuances

• Most candiduria is asymptomatic colonization, not true infection—symptoms are essential to distinguish infection from colonization 1, 2
• Pyuria and colony counts are unreliable for differentiating colonization from infection, especially in catheterized patients 1, 2
• Absence of symptoms does not require treatment in most patients, as asymptomatic candiduria represents benign colonization in >95% of cases 2

First-Line Treatment Algorithm

Step 1: Remove Predisposing Factors (Most Critical)

• Immediately remove any indwelling urinary catheter—this single intervention clears candiduria in approximately 50% of cases without antifungal therapy 1, 2
• Discontinue unnecessary broad-spectrum antibiotics, as these are major risk factors for candiduria 2
• Eliminate urinary tract obstruction if present, as obstruction prevents successful antifungal treatment 1, 3

Step 2: Determine Need for Antifungal Therapy

Treat if symptomatic OR if patient belongs to high-risk group:

High-Risk Groups Requiring Treatment (Even if Asymptomatic)

• Neutropenic patients with persistent unexplained fever and candiduria 1, 2
• Very low birth weight neonates (<1500 g) due to high risk of invasive disease 1, 2
• Patients undergoing urologic procedures or instrumentation within several days 1, 2
• Patients with urinary tract obstruction that cannot be promptly relieved 2

Do NOT Treat

• Asymptomatic, otherwise healthy patients—including those with diabetes or advanced age alone 2
• Asymptomatic non-neutropenic, non-catheterized patients—treatment provides no mortality benefit 2

Step 3: Select Antifungal Regimen Based on Species

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

Symptomatic Cystitis:

• Fluconazole 200 mg (≈3 mg/kg) orally once daily for 14 days is first-line therapy 1, 2
• This recommendation is based on the only randomized, double-blind, placebo-controlled trial demonstrating efficacy 2
• Fluconazole achieves high urinary concentrations that reliably eradicate the pathogen 2

Symptomatic Pyelonephritis:

• Fluconazole 200–400 mg (≈3–6 mg/kg) orally once daily for 14 days 1, 2
• Use the higher 400 mg dose when upper-tract involvement is confirmed by flank pain and fever 2

For Fluconazole-Resistant Species

Candida glabrata (often fluconazole-resistant):

• Amphotericin B deoxycholate 0.3–0.6 mg/kg IV daily for 1–7 days 1, 2
• OR oral flucytosine 25 mg/kg four times daily for 7–10 days (alone or combined with amphotericin B) 1, 2
• Flucytosine monotherapy is a weaker recommendation when amphotericin B is unsuitable 2

Candida krusei (intrinsically fluconazole-resistant):

• Amphotericin B deoxycholate 0.3–0.6 mg/kg IV daily for 1–7 days 1, 2

Refractory fluconazole-resistant cystitis:

• Bladder irrigation with amphotericin B 50 mg/L sterile water daily for 5 days can be attempted, though relapse rates are 80–90% 2

Step 4: Address Complicated Infections

Fungal Balls or Obstructive Uropathy:

• Surgical or endoscopic removal is mandatory in addition to systemic antifungal therapy—antifungal agents alone fail without drainage 1, 2
• For patients with nephrostomy tubes, adjunctive irrigation with amphotericin B deoxycholate 25–50 mg diluted in 200–500 mL sterile water is recommended 2

Patients Undergoing Urologic Procedures:

• Fluconazole 200–400 mg daily for several days before and after the procedure 2, 3

Critical Pitfalls to Avoid

• Never use echinocandins (caspofungin, micafungin, anidulafungin) or newer azoles (voriconazole, posaconazole) for urinary Candida infections—they achieve inadequate urine concentrations 2
• Never use lipid formulations of amphotericin B for Candida UTI—they do not attain adequate urinary levels 2
• Do not treat asymptomatic candiduria reflexively—most cases represent benign colonization and treatment does not reduce mortality 2
• In male patients, do not dismiss candiduria as simple colonization—evaluate for possible prostatitis if urinary symptoms develop 2
• Failure to remove indwelling catheters is the most common cause of treatment failure and relapse 2, 4

Monitoring and Follow-Up

• Candiduria progresses to candidemia in <5% of cases—it mainly serves as a marker of overall illness severity 2
• For recurrent candiduria after appropriate therapy, evaluate for underlying urologic abnormalities such as strictures, stones, prostatic disease, or persistent obstruction 2
• Monitor for emergence of urinary symptoms in patients initially managed with observation alone 2