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96 Cards in this Set
- Front
- Back
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What is the difference between human and fungal cell membranes?
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Human: cholesterol
Fungal: Ergosterol and a chitin cell wall |
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Where are antifungal medicines aimed?
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The ergosterol cell membrane
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3 ways fungi cause disease
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Producing mycotoxins
Posessing allergens Tissue invasion (mycoses) |
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What are mycoses?
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Tissue invasive fungi
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What are the two morphologies of fungus?
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Yeast (divide by budding, sometimes elongate into pseudohyphae)
Molds (structural units are hyphae) |
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What is a mycelia?
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An agregate of mold hyphae/filaments
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How ddo demonstrate fungi in tissues?
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KOH
Calcoflur white (make it fluoresce) Histopathology (GMS, PAS, H&E) Culture Detection of fungal antigens and metabolites |
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What do fungi look like on a gram stain?
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Gram positive
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What fungus do you see by india ink
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cryptococcus in csf
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What are some fungal culture media?
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Sabouraud dextrose agar (SDA)
Lactophenol cotton blue (LPCB) |
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Clinical features of deep mycoses?
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Few specific signs and sx
Early dx important for rx |
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4 types of fungal disease
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Cutaneous
Subcutaneous Dimorphic systemic Opportunistic |
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Where are systemic mycoses commonly found?
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Tropical countries
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What are the most common fungal infections of the tropics?
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Cutaneous (dermatophytes)
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What are the endemic systemic mycoses? (4)
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Those that can cause respiratory infection
Histoplasma capsulatum/duboisii Blastomyces dermatidis Paracoccidiodes brasiliensis Coccidiodes immitis |
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What is fungal dimorphism?
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Mold at 25-30C
Yeast or spherule at 37C |
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Describe histoplasma capsulatum dimorphism
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At 25C - macroconidia (mace like)
At tissue 37C, intracellular yeast in macrophages (like leishmaniasis) At lab 37, small single budding yeast |
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Describe blastomyces dermatidis dimorphism
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At 25C, hyphae withsingle microconidia
At 37 tissue, broad based single budding yeast (snowman) At 37 lab, snowman |
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Describe paracoccidiodes braziliensis dimorphism
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At 25C, hyphae with single microconidia
At 37 tissue, multiple budding yeast (cogwheel/paddlewheel) At 37 lab, multiple budding yeast |
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Describe coccidiodes immitis dimorphism
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At 25C, barrel shaped arthroconida (box cars)
At 37C, spherules with endospores At 37 lab, barrel shape arthroconidia (boxcars) |
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Which of the endemic systemic mycosis is biolevel safety 3?
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Coccidiodes immitis
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Which endemic systemic mycosis looks like a boxcar?
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Lab, coccidiodes immitis
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Which endemic systemic mycosis looks like a snowman?
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Blastomyces dermatidis (37 tissue and lab)
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Which endemic systemic mycosis looks like a cogwheel?
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Paracoccidiodes braziliensis - tissue 37
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Where is histoplasmosis found in the environment?
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High nitrogen soil -- chicken, starling, bat guano
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How do you catch histoplasmosis?
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Inhaled bat/chicken/starling guano -- spores
Not contageous |
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Where is histoplasmosis found in the US?
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Missisippi and Ohio river valleys
In the world, temperate and tropical |
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What is the clinical presentation of histoplasmosis?
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In healthy -- asymptomatic.
Mostly self-limited pulmonary infection In HIV, disseminated |
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What isthe pathology of histoplasmosis?
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Granulomas with caseastion, healing by firbrosis and calcification -- resembles TB
In disseminated, macrophages filled with yeast resembling leishmaniasis |
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What fungal infection resembles leishmaniasis?
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Histoplasmosis in disseminated form
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What fungal infection resembles TB?
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Histoplasmosis -- with caseating granulomas
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How to diagnose histoplasmosis
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Direct demonstration in tissue or buffy coat
Blood, bone marrow, sputum or skin samples |
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What is unique about African Histoplasmosis?
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Spares lungs. Causes bone, skin, soft tissue infection
Yeast cells are larger |
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What is the treatment for histoplasmosis?
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Itraconazole and amphotericin B
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Where in the world is Blastomycosis found?
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Missisppi river valley and SE US
Africa, Mexico and Central America |
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Describe the pathgenesis of blastomycosis
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Primary disease pulmonary
Secondary disease due to bloodborne spread from lungs to skin, bones, joints, rarely CNS |
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Describe pulmonary leasions of blastomycosis:
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Suppurative and granulmatous inflammation
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Describe skin lesions of blastomycosis
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Verrucoid raised lesions with microabscesses and ulceration
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What is the treatment for Blastomycosis?
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Itraconazole and amphotericin B
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Where in the world is Paracoccidiodomycosis?
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Latin america (Central Mexico to S. Argentina and Brazil)
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What kind of soil carries paracoccidiodomycosis?
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Soil where sugar cane and coffee grows
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How is paracoccidiodomycosis passed?
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Inhalation from environment
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Describe the pathogeneis of paracoccidiodomycosis
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Inhaled, causing lung dz like TB and other respiratory mycoses
Secondary disease by bloodborne spread to mouth and nose Can cause addison dz of adrenals in children |
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What systemic mycosis causes addison's disease in children?
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Paracoccidiodomycosis (21-80% of autopsy cases involve adrenals)
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What is the treatment of paracoccidiodomycosis?
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Itraconazole (not amphotericin)
Bactrim Sulfadiazine |
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What is south american blastomycosis
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Paracoccidiomycosis
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What is San Wakeen Valley Fever?
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Coccidiodomycosis
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Where in the world is coccidiodomycosis?
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SW US, Central/South america
Hot desert soil, semiarid |
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What is the treatment of coccidiodomycosis?
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Amphoterecin B
Variable response to axoles |
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Describe skin presentation of coccidiodomycosis
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Severe cutaneous presentation, resembles blastomycosis
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Describe coccidiodomycosis pulmonary presentation
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Often asymptomatic
Arthrtitis often accompanies acute lundg disease Secondary pulmonary disease is chronic cavitary (like TB) |
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What does disseminated coccidiomycosis do?
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Meninges
Bone Skin (common in californian philipinos) |
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What is the histopathology of coccidiodomycosis?
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Pyogenic and granulomatous dz (like blastomycosis)
Sphereules in tissue is diagnostic Sputum or tissue culture shows boxcars CLASS III BIOSAFETY! |
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Treatment of mild coccidiodomycosis?
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Mild - don't treat
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Treatment of pneumonia coccidiomycosis?
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At least 6 months
When chronic/progressive -- at least a year -- itraconazole betterthan fluconazole |
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Treatment of refreactory coccidiodomycosis?
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Amphotericin B, surgical resection
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Treatment of meningeal coccidiomycosis?
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Oral azole, lifelong!
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What to the dermatophytes infect?
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Keratin -- skin, hair, nails
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What does tinea versicolor look like under microscope?
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Spagetti and meatballs
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List the subcutaneous mycoses
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Sprortrichosis
Chromomycosis Chromoblastomycosis Mycetomas |
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What causes sporothirx schenckii
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Worldwide
Fungus of plants, moss, vegetation Acquired through skin trauma (gardeners, florists) |
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What does sporotrichosis infection look like?
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Ulcer, draining lymph node, no spread
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Can sporotrichosis go systemic?
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Rarely, to pulmonary form
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How to diagnose sporotrichosis?
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Dimorphic fungus, at 25C: mold with a daisy head appearance
At 37, yeast |
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What is the fugus of the florist?
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Sporotrichosis
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What does fixed sporotrichosis resemble?
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Dermal leishmaniasis
Lupus vulgaris Basal cell CA |
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Waht does lymphangitic sporotrichosis resemble?
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Diabetic leg ulcers (nodules becoming ulcers)
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What is the treatment of sporotrichosis?
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Saturated solution potassium iodide (SSKI)
Amphotericin B/Itraconazole for disseminated |
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What are chromomycosis?
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Deep skin fungal infections with pigmentation (chromo)
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What is the most common organism of chromomycosis?
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Fonseceae pedrosoi
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Where in the world is chromomycosis?
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Central/South America
Dominican Republic |
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Who gets chromomycosis?
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Traumatic innoculation with soil/plant/wood
Common in agricultural workers |
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What is the clinical presentation of chromomycosis?
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Starts as verrucoid, cauliflower lesion
Patients may present 5-15 years later when secondary bacterial infection leads to ulceration, pain, d/c |
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How diagnose chromomycosis?
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Copper pennies appearance of sclerotic bodies on KOH
Culture -- black molds, ID is difficult |
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How to treat chromomycosis?
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Difficult
Ketoconazole/itraconazole Excise small lesions |
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What is a mycetoma
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Firm, SQ, painless swelling with sinuses that extrude grains of organism
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What causes mycetoma
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Bacteria and fungus
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What is madruramycetoma
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Mycetoma caused by the fugus madurella spp
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How acquire maduramycetoma?
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Through soil
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Who gets mycetoma
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Young adults
Male > Female Bone commonly affected Legs > 75% of time |
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How diagnose mycetoma?
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Triad of painless swelling, sinus, grains
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Treatment of madura?
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Antifungals
Sometimes surgery |
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Three most common causes of mycetoma?
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Madurella mycetomatis
Exophiala jeanselmei Pseudoallesheria boydii |
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Name 4 common opportunistic mycoses
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Candida
Cryptococcus neoformans Aspergillus, Penicillium Zygomycosis (diabetics/alcoholics) |
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Where do you catch cryptococcus?
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Pigeon poop
In immunocompromised |
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What are the common systemic infections of cryptococcus?
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Meningitis, skin, bone, eye
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How to diagnose cryptococcus?
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India ink stain of CSF (due to large capsule)
Culture |
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What is the treatment of cryptococcus?
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Amphotericin B
Itraconazole |
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What organism causes a "starry sky" appearance?
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Cryptococcus under india ink stain
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Who gets Penicillium marneffei?
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Immunocompromised in SE asia (Thailand)
From BAMBOO RATS |
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What do bamboo rats carry?
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Penicillium marnieffei
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What organs are afffected by penicillium marnieffei?
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Lungs, skin, liver, spleen, bone marrow
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How to tell penicillium marnieffei from histoplasmosis?
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Divide by binary fission, not budding
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Diagnosis of penicillium marneffei?
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Direct demonstration in tissue
Culture |
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What is the clinical presentation of penicillium marneffei?
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Diffuse umbilicated papules with central necrosis resembling molluscum
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What does a cultured colony of penicillium marnefffei look like?
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red pigment
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