Systemic Mycoses Flashcards
(31 cards)
List of systemic mycoses
Histoplasma, Coccidioides, Blastomyces, Paracoccidiodes, Penicillum marneffi
Morphology of systemic mycoses
Histoplasma, Blastomyces, Paracoccidiodes, Penicillum marneffi are dimorphic: “mold in the cold, yeast in the heat”
1 exception is Coccidioides: “mold in the cold, spherule in heat”
Yeast forms have unique morphologies!
Transmission of systemic mycoses
For Histoplasma, Coccidioides, Blastomyces, Paracoccidiodes, Penicillum marneffi
Respiratory
No person-person
Clinical presentation of systemic mycoses
For Histoplasma, Coccidioides, Blastomyces, Paracoccidiodes, Penicillum marneffi
- Mostly asymptomatic unless immunocompromised. Need high infectivity dose to cause disease in immunocompetent person.
- All can cause Pneumonia and disseminate (Extrapulmonary Manifestation)
- can have latent period and reactivation disease.
Treatment of systemic mycoses
For Histoplasma, Coccidioides, Blastomyces, Paracoccidiodes, Penicillum marneffi
Azole for local infection
Amphotericin B for systemic infection
Histoplasma Capsulatum epidemiology
Inhaled microconidia (spores) from: spelunking, construction work, bat guano (high concentrations), Ohio and Mississippi River Valleys and other countries (Caribbean)
Histoplasma Capsulatum morphology
Dimorphic (mold/yeast), Intracellular (monocytes/macrophages ). In culture see it growing inside of macrophages. Smaller then RBC.
Histoplasma Capsulatum Clinical presentation
Dissemination/sepsis /reactivation in immunocompromised/defects in CMI with high mortality (>80%);
PULMONARY (can look like miliary TB, or regular TB with granulomas), cardiac, rheumatic conditions; can be asymptomatic
Histoplasma Capsulatum diagnosis
Most Important: Urine antigen test.
The possible other options: Visualization on sputum with silver stain, peripheral blood smear, bone marrow biopsy, Broncheoalveolar lavage; skin/liver/LN bx poor yield
Treatment of histoplasma capsulatum
Amphotericin B, Itraconazole, Voriconazole
Blastomyces Dermatitidis morphology
Dimorphic, saprophytic mold in soil (25C); Broad Based Budding yeast
“Blasto = Broad-Based Buds”
Same size as RBC.
Clinical presentation Blastomyces Dermatitidis
Pulmonary (chronic pneumonia); cutaneous lesions (papules, nodules, microabscesses – looks like mold) and bone lesions from hematogenous spread
ExtraPulm - “BLaST = Bones, Lungs, and Skin, (TB presentation)”
Diagnosis of Blastomyces Dermatitidis
Broad-based budding of yeast; silver stain
Epidemiology of Blastomyces Dermatitidis
Inhalation of spores (rarely cutaneous), environmental (soil, decaying wood, river banks);
geographic overlap with Histo: Great lakes and Ohio River valleys
Treatment of Blastomyces Dermatitidis
Amphotericin B, itraconazole, fluconazole
Coccidioides Immitis morphology
Dimorphic: multinucleate spherule and
mold (barrel-shaped arthroconidia is infectious unit).
Spherule filled with endospores in body, not yeast. Larger then RBC.
Coccidioides Immitis clinical presentation
Asymptomatic (many), flu-like symptoms (10-16 days post-exposure);
San Joaquin Valley Fever in 5% (rash, erythema nodosum (desert bumps), erythema multiforme, joint pain, conjunctivitis);
may disseminate MENINGITIS
Diagnosis of Coccidioides Immitis
LARGE spherule in culture, PPD-like skin test (type IV hypersensitivity)
Epidemiology of coccidioides Immitis
Soil in SW US, Latin America; disturbed soil (inhaled spores, which becomes LARGE spherule) –>Military, Archaeologists, Construction workers. Increased rate after earthquakes
“Cocc your gun in the South and knock over a Barrel of spores”
genetic high risk groups: Filipino>African-American>Native Americans
Treatment of coccidioides immitis
Amphotericin B (+ fluconazole if immunocompromised)
paracoccidioides brasiliensis morphology
Dimorphic, Mariner’s Wheel (multiples buds w/ narrow stalks)
“Paracoccidio parasails with the Captain’s Wheel all the way to Latin America”
Paracoccidioides brasiliensis clinical presentation
Lungs –> dissemination; LONG latency (can be > 10 yrs); PULMONARY (necrotizing granulomas, dry cough), lymphadenopathy, sometimes cutaneous fistulae; CXR shows patchy nodular densities and sometimes consolidations; can be asymptomatic
Paracoccidioides brasiliensis diagnosis
Culture of biopsy or bronchoalveolar lavage budding yeast with Mariner’s (captain’s) wheel appearance
Paracoccidioides brasiliensis epidemiology
Latin America (Mexico to Argentina; highest in Brazil); 15:1 male predominance (estrogen may be protective); inhaled spores “Paracoccidio parasails with the Captain’s Wheel all the way to Latin America”
