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Flashcards in Systemic (Endemic) Mycoses Deck (38):
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@ 37C

mold 2 yeast

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@ 25C

yeast to mold

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Coccidioidomycosis

C. immitis (CA), C. posadasii (outside CA)Valley feverSW US

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Coccidioides spp MORPHOLOGY

DimorphicSPHERULE W/ENDOSPORESArthoconidium

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Coccidioides spp PHYSIOLOGY

Soil organismWhite, wooly colony

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Coccidioides spp SPHERULE

Lipid rich20-80um diameter, located inside giant cell"endosporulating spherule"Susceptible tissues: lungs, skin, cardiac, pericardium, bones, CNS

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Coccidioides immitis

Sabouraud agar - woolyslow-growing (1-2wk)

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Antigens for immunodx: C. immitis

CoccidioidinSpherulin

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C. immitis PATHOPHYSIOLOGY

Involves pulmonaryInhale arthroconidia-- transforms into pulmonary spherules that contain endospores.Endospores released, produce new spherulesSeptate hyphae & arthroconidia sometimes present in pulmonary cavitiesPrimary disease: self-limited influenza-like illnessMay develop into diffuse pneumoniaPossibly asymptomatic

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C. immitis PATHOGENICITY (disseminated)

May involve lungs, skin, bones, joints, CNS (rarely)IMMItis affects IMMIgrants& preggos (elevated estradiol/progesterone enhances growth)Erythema nodosum - delayed hypersensitivity to fungal antigens (good prognosis)

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Coccidioides EPIDEMIOLOGY

Airborne (not communicable)Soil-dwelling: arthroconidiaMore common in older adultsIncreasing number of cases

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Coccidioides ID/DX

PAS exam: giant cells/spherulesCulture on Sabouraud agarincreased IgM/IgG

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Coccidioides THERAPY

Fluconazole Itraconazole Amphotericin BFor disseminated disease - long term treatment

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Coccidioides CONTROL

Dust protectionPave roadsPlant vegetaionNo vaccine

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Coccidioides CASE STUDY

Scaly, verrucous rash (&lesions)Involvng nose, head, torso//chronic cough/low-grade fever//persistentrecurrent rashSouthern CAnight sweats/arthralgia/back painpositive IgG/IgM antibodiesGranulomatous inflammation & fungal spherules w/in multinucleated giant cells

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Histoplasma capsulatum MORPHOLOGY

DimorphicUninucleate budding cells (blastoconidia)Mold features: micro & tuberculate macroconidia

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Histoplasma capsulatum PHYSIOLOGY

Facultative intracellular parasite (macrophages/PMNs)Culture: yeast @ 37C; mold: 25C

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Histoplasma capsulatum PATHOPHYSIOLOGY

Influenza-like to severe lung diseaseRETICULOENDOTHELIAL DISEASEMicroconidia are inhaledDevelop into yeast cellsCells may be phagocytosed/disseminated

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Histoplama capsulatum: HISTOHIO BATS YEAST IN ALL FIGHTS W/P'S & N'S

Granulomatous foci

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Histoplasma capsulatum

FeverPulmonary illnessWeight lossGI involvement

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H. capsulatum VFs

Yeast releases urease, ammonia, bicarbonateEnables yeast to raise pH & blunt or eliminate killing action of phagolysosome

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H. capsulatum - host resistance

PMN expresses fungistatic activity & functional T cell-mediated immunity is critical for clearance

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H. capsulatum EPIDEMIOLOGY

Ohio/MS River valleysNot communicableBat's intestine

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H. capsulatum ID

Microscopic - intracellular yeastCulture - tuberculate macroconidiaDetection of antigen or antibody (histoplasmin)

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H. capsulatum THERAPY

Chronic pneumonia & disseminated disease - itraconazole /amphotericin B

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Antigen for immunodiagnosis (H. capsulatum)

Histoplasmin

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H. capsulatum CONTROL

Protection from dust

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H. capsulatum CASE STUDY

Marked weight loss, diarrhea, dry cough, fever, night sweats.Multiple nodular lesions found in lungVegetating ulcerous lesionYeast cells w/in macrophages

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Blastomycosis

Chronic granulomatous disease

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B. dermatitidis MORPHOLOGY/PHYSIOLOGY

Thermally dimorphicBroad - based yeast in tissue/exudateHyphae bear conidia/chlamydospores

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B. dermatitidis PATHOPHYSIOLOGY

Inhale infective stage (microconidium in soil)May produce acute/chronic pulmonary diseasePossibility of dissemination

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B. dermatitidis EPIDEMIOGY

Not communicable person to person: soil organism

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B. dermatitidis ID/DX

Metastatic skin lesionsBroad-based yeast (KOH, sputum/exudate/biospy)Culture on Sabouraud agar

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B. dermatitidis THERAPY

Disseminated disease requires aggressive therapyDOC: itraconazole / amphotericin B

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B. dermatitidis CLINICAL PERSPECTIVE

persistent fever/cough/yellow sputumChest radiograph: unilateral pleural effusionProfound weight loss/ulceronodular lesion on the handBroad-based budding yeast in PAS-stain reveals fungal etiology

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Paracoccidioidiomycosis

P. brasiliensis"mickey mouse"

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P. brasiliensis

Yeast w/multiple budsPossibly self-limitingConfined to central/south americaTherapy: itraconazole/amphotericin B

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P. brasiliensis CASE STUDY

71 y/o Chinese manchronic cough/malaise for 2 mo4-mo vaca in AZlow-grade fevernecrotic granulomatous inflammation w/multinucleated giant cells containing spherulespositive PAS