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35 Cards in this Set
- Front
- Back
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5 risk factors for invasive fungal infections
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-underlying disease and tx (like lung transplant or neutropenia)
-corticosteroids -GVHD (very high risk) -Concomitant infections -Catheters |
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Why are GVHD pts at higher risk for invasive fungal infections?
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Taking immunosuppressants
breakdown in mucosal barriers |
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6 issues with fungal infections (clinical resistance)
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wrong dx
level of immunosuppression high organism burden at start of therapy toxicity of antifungals site of infection Length of tx |
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Medically important yeast
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Candida, cryptococcus neoformans
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medically important molds
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Zygomycetes (non-septate)
Aspergillus, fusarium (septate) |
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3 medically important dimorphics
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Histoplasma
coccidoides Blastomyces |
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Distribution of Cryptococcus neoformans
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worldwide
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Which is most common in patients with defects in T-cell immunity?
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Cryptococcus neoformans
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How is cryptococcus neoformans infection obtained?
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Inhalation of yeast
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What is the key virulence factor in cryptococcus neoformans?
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capsule (also causes meningitis)
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When is the risk of meningitis from cryptococcus neoformans highest?
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AIDS pts with CD4 counts <100 cells/microL
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What can happen with Cryptococcus neoformans meningitis?
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CSF findings normal or minimally abnormal
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What exam should be used to diagnose cryptococcus neoformans?
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Antigen detection test (bc CSF is normal)
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What two pts often present to UNC with cryptococcus relapse?
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Not knowing they have AIDS, stopping fluconazole tx
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Who gets in trouble with Aspergillus?
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Pts who can't clear spores (normally exposed to 300/hr)
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2 lines of defense of aspergillus
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pulmonary macrophages engulf conidia
neutrophils attack escaped hyphae |
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Why are neutrophils important to clear aspergillus?
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Attack hyphae
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4 types of aspergillus
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invasive
aspergilloma allergic bronchopulmonary aspergillosis (ABPA) Allergic fungal sinusitis |
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Sickest of the aspergillus infection
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acute invasive aspergillosis (greatest immune weakness)
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What do zygomycoses have?
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Broad hyphae with few septations
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Who gets zygomycosis?
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Diabetics (esp DKA)
Chronic steroid use burn/trauma (grows on burn) immunocompromised |
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Which is frequently confused with aspergillus bc it invades with hyphae?
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Fusarium (high mortality in neutropenic pts)
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Where are conidia trapped with Fusarium?
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nose (10x bigger)
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What is used to dx pneumocystis jiroveci?
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direct fluorescent exam only (doesn't culture and PCR not good)
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What is needed for PCP diagnosis of sample?
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Bronchoscopy (non-productive cough, but in base of lung)
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Drug for PCP
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sulfa/trimethoprim
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dimorphic fungi: which stage is infectious?
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mold is infectious; yeast is pathogenic
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How are dimorphic fungi spread?
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spores from environment: not person to person
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Coccidioides is found where?
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SW USA, Northern Mexico
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What is the issue with Coccidiodes under culture?
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shift to arthroconidia, which are highly contagious through air.
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High risk area of Histoplasma
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Ohio and Mississippi River valleys, caves
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Which fungus looks like small, lemon shaped yeast?
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Histoplasma
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What can Histoplasma mimic?
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Tb
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What are the dimorphic fungi most commonly seen at UNC?
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Histoplasma
Coccidioides Blastomyces |
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Which fungus is more likely to have skin lesions and GU tract infections in males?
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Blastomyces dermatitidis
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