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97 Cards in this Set
- Front
- Back
5 dimorphic fungi
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Histoplasma, Sporothrix, Blastomyces, Coccioides, Candida,
(HSBC C) |
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Do fungi produce endotoxins?
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No
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Where is Histoplasmosis endemic?
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Ohio and Mississippi River Valley, tree choppers
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Where is Coccidioidimycosis endemic?
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Southwest US, CA earthquakes
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Polysacc Capsule unique to which fungus?
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Cryptococcus
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Candida host damage vs response curve
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quarterpipe downward
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Candida high risk pop?
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1. Meds: Abx users, steroid users
2. Immunosuppressed: HIV, Neutropenics, surgery |
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Large source of Cryptococcus?
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bird feces, pigeon poo
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Cryptococcus neoformans causes.....
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pneumonia, meningoencephalitis, skin lesions in cooler temps esp serotype D, osteolytic bone lesions
(PMSO) |
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Why is Pneumocystic Carinii unique?
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not free living, no cell wall, treat with abx not antifungals, cannot be cultured, not a human commensal, not acquired from environment
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Normal opening pressure upon lumbar puncture
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~130
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Cryptococcus neoformans predisposing conditions are?
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Meds: glucocorticoids, TNF inhibitors, transplant pts,
Diseases: AIDS, lymphoma, sarcoid (A-L-S) |
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Cryptococcus virulence factors are?
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Ability to grow at 37C and thrive in macros
Polysacc capsule Melanin, Mannitol |
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How do you diagnose Cryptococcus neo?
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Blood Culture
Cryptococcal Ag Serology Lumbar punct: india ink positive CSF culture |
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What criteria do AIDS pts or immunocompromised have to achieve so as to not get recurrent cryptococcus?
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CD4 count >200
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Spelunkers and tree cutters get?
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Histoplasma capsulatum
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Histoplasma path?
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Inhale microconidia,
convert to yeast, taken up by phagos and replicate |
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Clinical manifestations of Histoplasma?
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TB like symptoms:
Cavitary histo from underlying COPD Mediastinal fibrosis |
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How do you diagnose Histoplasmosis?
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sputum and blood culture (slow),
bone marrow biopsy, serology, skin testing |
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Med students that open petri dishes get?
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Coccidioides
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2 dimorphic forms of Coccidioides
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in culture or soil: arthroconidia
in host: spherules with endospores |
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Endemic areas of Coccidioides are?
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hot arid areas of S. American and United States
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Coccidioides path
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inhaled arthroconidia swell to spherules--> endospores
TB like infection in lung that gets into blood rare Meningitis |
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Coccidioides most likely causes what and where?
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Community acquired Pneumonia in AZ or nearby states
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Endemic areas of Blastomyces dermatitidis?
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River Valleys
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3 characteristics of Blastomyces
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1.Thick walled yeast with broad based buds
2. Inhaled causes TB like symptoms, skin and bone symptoms, and meningitis, 3. WI-1 cell adhesin is main virulence factor |
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Diagnosis of Blastomyces dermatitidis
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direct exam of tissue, culture, serology lacks spec/sens
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What do florists and twiggy wood workers get?
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Sporothrix schenckii
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Sporothrix schenckii causes what?
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Lymphangitic sporotrichosis: nodule at and along lymphatic sites
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Clinical symptoms of Sporothrix schenckii?
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plaque sporotrichosis: nontender red maculopapular granuloma limited to inoculation site
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How do you diagnose Sporothrix schenckii?
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Culture skin biopsy or pus
should see *asteroid bodies* = yeast cell w/ eosinophilic radiations |
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Most common source of Candida?
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Host's own endogenous flora
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Candida virulence factors?
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adherence
biofilms proteinases phospholipases phase variation |
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Candida risk factors?
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OR: Catheters, surgery, burns, abx, chemoTx, tube feeding
Transplants: Steroids, Bone Marrow Transplantation Diseases: HIV, DM, Neutropenia |
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Candida damage vs host response curve?
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Quarter pipe downward
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What does Candida look like? where?
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sharply demarcated at folds of skin
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Most common endocrinopathy in mucocutaneous Candidiasis?
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hyper PTH
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When do you clearly see hepatosplenic candidiasis?
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upon return of neutrophils
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How do you diagnose muco/cutaneous Candiasis?
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scrapings w/ 10% KOH
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Best stain for Candida?
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Silver stain
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How do you treat symptomatic candiduria?
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Remove the catheter
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How do you treat life threatening Candidiasis?
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With a Volleyball! (AVP)
Amphotercin, Voriconazole, Pneumocandin (echinocandin) unless it's C. Parapsilosis |
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How do you treat Candida in neonatal ICU?
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Azoles + Ampho because babies have less toxicity from Ampho
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How do you treat life threatening Candidiasis in certain pts?
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Fluconazole, except for C. krusei, glabrata, and tropicalis
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How do you treat Candidiasis thrush?
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Clotrimazole, nystatic topicals
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How do you treat Candida vaginitis?
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One dose Fluconazole
(Or Nystatin topicals, OR Azoles.) |
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How do you treat Candida esophagitis?
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Fluconazole
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Is Aspergillus dimorphic?
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No. Only hyphal.
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Which Aspergillus spp produce aflatoxin?
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A. flavus and A. parasiticus. Can cause liver cancer.
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Damage vs host response curve of Aspergillus?
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U shaped. bottomed out. Class 4.
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3 types of pulmonary hyperresponsiveness to Aspergillus?
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Asthma,
Allergic Bronchopulmonary Aspergillosis (ABPA) Extrinsic Allergic Alveolitis "Farmer's lung", |
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Treatment of Allergic Bronchopulmonary Aspergillosis (ABPA)?
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Azoles + Steroids
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What kind of fungus formation is common w prior cavitary TB?
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Aspergilloma
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Symptoms of Aspergilloma?
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Cough
Clubbing, Wheezing Watch out for massive hemoptysis. |
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3 molecular host responses to Aspergillus infection?
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1. Macro dectin1 and TLR2/4 bind beta-glucans on Asp--> inflamm cascade
2. Prod of O2 radical spp 3. Neutro prod of Lactoferrin: takes Fe awway from conidia |
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Risk factors for invasive Aspergillosis?
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Transplants, neutropenia, steroids, AIDS, chronic lung disease, burns
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Symptoms of Invasive Pulmonary Aspergillosis?
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none early,
cough, low grade fever, chest pain, hypoxia |
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2 radiological signs of Invasive Pulmonary Aspergillosis?
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"Halo sign" and "Air Crescent sign" cavitation--> hemoptysis can be fatal
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which Aspergillus species causes Aspergillus sinusitis?
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A. Flavus
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What is the most common site of disseminated Aspergillosis?
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brain
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How do diagnose Aspergillosis?
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requires tissue and special silver stain
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How do you treat invasive Aspergillosis?
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Volleyballs again!
Amphotercin, Voriconazole, Pneumocandin, or a combo of 2 |
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How do you treat semi-invasive Aspergillosis?
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Itraconazole or (better) Voriconazole
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How do you treat Aspergilloma?
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Surgery, Itraconazole/Voriconazole
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How do you treat ABPA?
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Itraconazole + steroids
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Where do Zygomycetes live?
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Soil
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3 modes of transmission for Zygomycetes?
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1. Breathe spores
2. Touch it 3. fermented milk/corn products or herbal remedies |
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Risk factors for Zygomycosis?
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DESFEROXAMINE Tx where Zygomycetes can scavenge Fe
Neutropenia, DM/DKA, steroids, transplants, broad spec abx, Burns |
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Common facial form of Zygomycosis?
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Rhinocerebral Zygomycosis: facial pain, fever, rapid progression
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Areas that Zygomycosis can go to?
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Pulm, GI, Face, skin
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What do Zygomycetes look like?
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Right Angle Ribbons
nonseptate irregular hyphae |
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How do you treat Zygomycosis?
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Debridement + high dose Ampho
OR Posaconazlole with Echinocandin |
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What does Tinea corporis (ringworm) look like?
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circumscribed, serpiginous inflammatory border
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How do you diagnose Dermatophytes?
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scrape, 10% KOH, some spp fluoresce under UV light
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Young people get this. rash. spring break. Puerto Rico.
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Malassezia furfur
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Why do young people get Malassesia furfur?
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Cause it's lipophilic. Hormonal changes cause changes in sebaceous glands.
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Clinical manifestation of Malassesia furfur? (Pityriasis versicolor)
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rash on back, chest, abdomen, neck, upper limbs
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Mechanism of AmphotercinB?
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macrolide ring interacts with cell mem ergosterol to form holes through membrane
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Although resistance to Ampho is rare, which species have it?
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Malassezia furfur, Aspergillus terreus, Candida lusitania, others
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How do you treat oral candidiasis?
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Oral slurry of AmphoB
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Toxic side effects of AmphotericinB?
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fever, chills, arrhythmia, hypotension, type1 renal tubular acidosis, K and Mg wasting, renal failure, anemia. watch those on other nephrotoxins and those on heart meds
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How has Ampho been improved?
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combine with liposome: less nephrotoxic, higher levels, but expensive
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Mech of Flucytosine?
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Inhibits DNA and RNA synthesis
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How do you treat cryptococcal meningitis?
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AmphoB+Flucytosine b/c excellent penetration to CSF
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Toxic side effects of Flucytosine?
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bone marrow suppression
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What's the only available formation of Flucytosine?
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PO
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Mech of Azoles?
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Inhibits ergosterol synth by inhibiting C14 demethylation of lanosterol
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Differences b/w Fluconazole and Itraconazole
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Fluconazole has better CSF levels, renal excretion. Itraconazole absorption enhanced by acid/food, poor CSF penetration, hapatic excretion
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Toxic side effects of Azoles?
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interaction with drugs that affect cytochrome P450s. Liver failure.
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Which drug is interchangable with Fluconazole?
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Voriconazole
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Interesting side effect of Voriconazole?
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see yellow flashing lights: photopsia
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Drug given in many places for prophylaxis before bone marrow transplants? What about the drug makes it good?
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Posaconazole, long half life and no P450 induction
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Echinocandin (Pneumocandins) mech?
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Inhibit 1,3 beta glucan synthase (component of many fungal cell walls)
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What two types of fungi are susceptible to Pneumocandins?
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Aspergillus, Candida
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What important type of fungus is resistant to Pneumocandins?
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Cryptococcus neoformans cause it has 1,6 beta glucans in cell wall
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Tox side effects of Pneumocandins?
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phlebitis, fever, cyclosporin increases levels, tacrolimus decreases levels
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How do you treat Dermatophytes?
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Griseofulvin, terbinafine (Lamisil), topical azoles, heat treatment
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