Fungal Lung Diseases

Question 0

Histoplasma

Answer 0

-*dimorphic fungus
-in vivo (37d)-small yeast (in/out MACs)
-envt (20d)-mold w/ small teardrop-shaped microconidia and *tuberculate cacroconidia
-septate hyphae
-infx form: conidia (microconidia)
-soil w/ high N2 from crap
-spores have projections
Pathogenesis
-infx of reticuloendothelial system (RES) w/ growth in UNactivated MACs
Disease
-mostly asymptomatic to mild pulm disease
-severe pneumonia
-chronic cavitary pulmonary histoplasmosis
-acute disseminated histoplasmosis

Question 1

Coccidioides

Answer 1

-dimorphic fungus
-37d (tissue form)–>spherules containing endospores
-25d (soil, culture)–>mycelial (mold) form
-asexual spores=arthroconidia
-septate hyphae
-grow in soil–>inhaled airborn *arthrospores=arthroconida=asexual spores–>lungs
Virulence
-most important RF for dissemination=DEC cell mediated immunity
Disease
-causes Valley Fever (coccidiodomycosis)
-risk for immunocompetent; disseminates to bone, meninges, pregnant, blacks, filipinos
Diagnostic
-*serology (many options)
-SDA/SABH

Question 2

Blastomyces

Answer 2

-*dimorphic fungus
-in vivo big broad-based budding yeast
-envt (20d)-mold w/ septate hyaline hyphae
-lollipop conidia (infx!)
Disease
-causes blastomycosis
-single or multiple cutaneous lesions (crap on face)
-verrucous, irregular gray or violet borders; possible microabscesses and ulcerations
-severe pneumonia
-disseminated blastomycosis (to any organ)

Question 3

Paracoccidioides

Answer 3

-*dimorphic fungus
-in vivo- yeast w/ multiple narrow based buds, resembles *pilot wheel
-envt (20d)- mold-hyaline septate hyphae
-intracellular parasitism in MACs
Disease
-causes paracoccidioidomycosis
-asymptomatic to pulmonary to disseminated
-secondary ulcerated lesions of face, mouth/buccal, nasal or GI mucosa

Question 4

Cryptococcus

Answer 4

-C. neoformans, C. gattii
-encapsulated yeast in/out MACs
-narrow-based bud
-urease+
Cryptococcus neoformans
-worldwide
-soi, rotting vegetation
-opportunist, attacks immunocompromised
Virulence
-fac. intracellular in UNactivated MACs
-large polysaccharde capsule
-phenol oxidase (laccase) to melanin
-urease
Cryptococcus gattii
-worldwide
-found in tree species (eucalyptus, fir, cedar)
-*primary pathogen
Disease
-causes cryptococcosis
-pulm lesions can be granulamotous=cryptococcoma
-common in AIDS pts
Diagnosis
-India ink stain for capsule

Question 5

Aspergillus

Answer 5

-filamentous fungus (mold)
-septate hyphae w/ 45 degree, V-shaped, dichotomous branching
-conida(chains) ubiquitous
-opportunist
Virulence
-angioinvasive
Disease
-causes aspergillosis
-in neutropenic
-aspergilloma (fungal ball)-saprophytic colonization of preformed cavities, usu 2nd to TB=asymptomatic
-fever, pleuritic chest pain, cough, hemoptysis, dyspnea
-common manifestations: #1*brain abscess, necrotic skin lesions
Diagnostic
-ELISA; **Galactomannan antigen

Question 6

Pneumocystis jirovecii

Answer 6

-atypical fungus
-cholesterol instead of ergosterol in CM
-leading cause of morbidity and mortality in HIV pts
Virulence
-extensive antigenic variation major surface glycoprotein
Disease
-causes pneumocystosis
-causes pneumocystis pneumonia
-typically diffuse, bilateral interstitial infiltrates;ground-glass appearance
-*alveoli filled w/ foamy (“fluffy”) proteinaceous material
-major risk factor: *T-cell deficiency (HIV pts! CD4<200cells)
-can disseminate to liver, spleen, kidneys, brain