Genitourinary Fungal Infections

CANDIDIASIS

  • Bladder involvement may be asymptomatic or present with urgency, hematuria, frequency, nocturia, severe dysuria, and suprapubic pain.
  • Upper tract involvement may be signaled by symptoms and signs of pyelonephritis, perinephric abscess, or obstruction from fungus balls.
  • Systemic candidiasis usually involves lungs or kidneys and presents with fever, shaking, chills, hypotension, lethargy, petechiae, and embolic phenomena. Candidemia, when associated with bacterimia, portends a poor prognosis for the patient.

Diagnosis

  • Blood and urine cultures must be evaluated in the context of clinical setting, as candidemia and candiduria may occur as transient phenomena
  • Diagnosis of fungal cystitis is based:
    • Clinical presentation of irritative bladder symptoms
    • History of predisposing factors
    • Positive urinary fungal cultures (greater than104 CFU/mL, however, in presence of an indwelling catheters, these counts cannot be used to differentiate colonization from true infections)
    • Negative bacterial and acid-fast cultures
    • Cystoscopy and bladder biopsy to rule out tumor
    • Tissue cultures
  • Blood cultures, opthalmologic examination, and serum agglutinin titers may help to diagnose systemic involvement. Fungal infections are a difficult diagnostic problem, however, recent advances in molecular biology particularly, the polymerase chain reaction test, promise to detect Candida accurately and promises to be a valuable diagnostic tool of the future IVU may show calyceal defects and ureteral obstruction (fungal masses or bezoars)

Medical Management

  • Asymptomatic candiduria implies a colonization of the urinary tract without tissue invasion
    • Usually disappears when predisposing factors (antibiotics, indwelling catheters) are removed
    • Urinary alkalinization with sodium bicarbonate to a pH of 7.5 is helpful
  • Symptomatic or intractable vesical candidiasis (higher than 15,000/CFU) can be treated with systemic (see treatment of systemic infections) and /or intravesical antifungal agents. Various intravesical irrigations agents have been used with success such as amphotericin B (50 mg in 1000 mL of 5% dextrose water solution per 24 hr as a continuous drip) and miconazole (50 mg/1000 mL of normal saline/day) is an alternative bladder irrigant. Local therapies must be undertaken after the obstructive disease has been corrected and an invasive disease has been excluded.
  • Renal and systemic involvement. Three major drugs commonly used for GU candidiasis are fluconazole, flucytosine, and amphotericin B
    • Fluconazole (Diflucan).
      • Administered orally and intravenously
      • Can also be used for bladder irrigations quite effectively
      • Usual PO dose is 150 mg/day X 7 days for superficial bladder infections
      • It has excellent clinical efficacy in systemic candidiasis and comparable success rates with amphotericin B in the treatment of candidemia
      • Adverse effects include nausea, headache, skin rash, and hepatotoxicity
    • Flucytosine (5-FC Ancobon).
      • Oral agent
      • Interferes with fungal synthesis of DNA
      • Toxicity includes nausea and vomiting, rash, diarrhea, hepatic dysfunction, and bone marrow suppression
      • May be used alone in urinary candidiasis; used with amphotericin B in systemic disease.
    • Amphotericin B (Fungizone)
      • Intravenously administered macrolide antibiotic, combines with sterols in cell membranes
      • Mainstay of treatment in the critically ill patient with disseminated infection
      • Toxicity is quite common and noted in more than 85 percent of patients. It includes fever, hypotension, dyspnea, and nephrotoxicity
      • Synergistic with flucytosine

    Surgical Management

    • Ureteroscopy
    • Percutaneous nephrostomy along with irrigation and removal of fungal bezoars and placement of drains and stents may be required to rid the patient of fungus. This may be followed by continuous irrigation with an antifungal agent.

References


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