Card Set Information

2011-08-22 21:32:11
Fungal infection

Fungal Infections & Tretaments
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  1. Yeasts
    Candida & Cryptococcus. Tend to be round & produce a capsule that shows a halo-like appearance on India ink staining. Characterized by psuedohyphae with a pinched-waist appearance
  2. Moulds
    Aspergillus; Fusirium; & Zygomycetes. Exhibit true hyphae with walled-off septae (no pinching)
  3. Mixed
    "Histoplasma; Blastomyces; Ciccidiomyces; & Sporothrix. ""Yeast in the heat; mold in the cold.'"
  4. Common fungal infections after human stem cell transplant
    Aspergilliosis (44%); Candidiasis (29%); Zygomycosis (7%); Fusariosis (3%); Cryptococcosis & dimorphic fungi (1%)
  5. Aspergilliosis
    Spores tend to be inhaled and cause airway disease (lungs; trachea; or bronchioles). Sinus & skin manifestations may also be present. In rare cases may become disseminated & can infect the CNS. On CT - appear as nodules with ground glass halo or an air crescent appearance. Preferred treatment: Voriconazole with or without Echinocandin
  6. Zygomycosis
    Risk factors = neutropenia & immunocompromised. Spores are inhaled & deposited on mucosa & then germinate & invade tissues. Angioinvasion results in tissue necrosis. Often manifests as a severe & rapidly progressing sinus infection w/ pain behind the eye & proptosis. Altered mental status may be present. Pulmonary manifestations are also common. Cultures tend to grow vertically and may even push the lid of the culture dish off. Preferred treatment: Amphotericin B or Posaconazole
  7. Candidiasis
    May be symptomatic or asymptomatic (asymptomatic only requires treatment for neonates; immunocompromised; and those about to undergo a GU procedure). May manifest as a UTI; pneumonia; mucocutaneous; in tissue (especially spleen/liver); or as a systemic infection (bloodstream - systemic symptoms; may cause endocarditis). Preferred treatment: systemic - Echinocandins; mucocutaneous - topical azole or Fluconazole
  8. Polyenes
    Act on ergesterol to disrupt fungal cell membranes - cause pore formation. Includes Amphotericin B
  9. Azoles
    Inhibit ergesterol synthesis - disturbs fungal cell membrane formation. IV or PO. Inhibit cytochrome P450 - causes some crossover side effects in humans (hepatic injury & drug interactions). Topical azole preferred for treatment of mucocutaneous candidiasis
  10. Terbinafine
    Allylamine that inhibits ergesterol synthesis - disturbs fungal cell membrane formation. Accumulates in hair & nails - effective on dermatophytes that cause nail infections & athletes foot. Metabolized hepatically & cleared renally. Side effects: GI upset; LFT increase; liver failure
  11. 5-fluorocytosine
    Inhibits DNA synthesis. Used only as adjunct therapy in serious yeast infections. PO only. Side effects: bone marrow suppression; GI upset: LFT increase
  12. Echincandins
    Glucan synthetase inhibitors - cause the cell wall to become fragile & rupture easily. IV only. Includes anidulafungin; caspofungin; micafungin. Side effects: increased LFTs; anemia; thrombocytopenia. Cleared through the liver with little metabolism. Preferred for treatment of systemic candida & pulmonary cryptococcus
  13. Amphotericin B
    IV only. Preferred for treatment of Zygomycosis & disseminated cryptococcus
  14. Fluconazole
    Side effects: GI upset & LFT increase; causes minimal drug interactions. Preferred for treatment of mucocutaneous candidiasis
  15. Voriconazole
    Side effects: LFT increase; altered vision; hallucinations; GI upset; many drug interactions (inhibits Cyp3A4). Preferred for treatment of aspergilliosis
  16. Posaconazole
    Side effects: LFT increase & GI upset. Drug interactions with tacrolimus & sirolimus & midazolam. Preferred for treatment of Zygomycosis