L23- RTI VIII Flashcards
list the common primary pathogens for fungal pneumonias / RTIs
(healthy and immuno-compromised)
- histoplasma capsulatum
- blastomyces dermatidis
- coccidioides immitis
- paracoccidioides brasiliensis
list the opportunistc pathogens for fungal pneumonias / FTIs
(immuno-compromised)
- cryptococcus neoformans
- aspergillus spp.
- pneumocystis jirovecii
Fungal RTIs are usually transmitted via (1). All infective fungi have the (2) property, allowing it to convert (3). (4) is another key factor to consider when suspecting or diagnosing a fungal RTI.
1- inhalation of spores from the environment (no person to person)
2- thermal dimorphism
3- convert from molds to yeast and back based on temperature
4- geographical relevance
Fungi:
- (1) form in environment
- (2) form in tissues
(1)/(2) is the replicative form
1- molds / mycelial form (30-33C)
2- yeasts (37C) — *replicative form
(indicate what this group represents) list the associated clinical disease for each of the following:
- (1) histoplasma capsulatum
- (2) blastomyces dermatidis
- (3) coccidioides immitis
- (4) paracoccidioides brasiliensis
(primary fungal pathogens --> affect healthy and immuno-compromised) 1- histoplasmosis 2- blastomycosis 3- coccidioidomycosis 4- paracoccidioidomycosis
indicate the fungal species represented by the following geographical areas:
- (1) Mississippi River Valley and Ohio River Valley
- (2) Southwestern USA, Northwestern Mexico
1- histoplasma capsulatum, blastomyces dermatidis
2- coccidioides immitis
Many fungal infections are commonly (1) and others will commonly mimic (2). General lung symptoms include (3) and other symptoms include (4). Although (4) are present, (5) is unusual in fungal infections
1- asymptomatic
2- Tb (or atypical pneumonias)
3- mild dry cough, progressive dyspnea, (hemoptysis- aspergillosis)
4- mild fever, weight loss, granulomatous lesions (skin / mucous membranes), Rheumatological syndromes
5- dissemination (spread into blood)
how does a fungal RTI appear on CXR
- pulmonary nodules
- hilar lymphadenopathy
- patchy infiltrates
_____ respiratory fungi is capable of growth within alveolar macrophages, explain (hint- 3 reasons)
histoplasma capsulatum:
- intracellular microbe (alveolar macrophage), although does not have a capsule
- inc phagolysosomal pH
- interferes with enzyme activity and Ag processing
uptake of _______ into fungi in the body is very important to its growth and development
Fe uptake
Fungal RTI diagnosis:
- (1) are the samples that can be taken
- fungi are placed on (2) agar and observed via (3)
- (4) is another possible diagnostic test
1- sputum, bronchoalveolar lavage, transtracheal aspirate, lung biopsy
2- Sabouraud’s agar
3- direct microscopy (large species) w/ staining (Giemsa, indirect FA stain)
4- PCR (nucleic acid probes)
(1) testing is very limited in terms of fungal RTIs because of (2). (1) is mostly used for testing for (3) infections among of the fungal RTIs, where it tests for Ig(4) from (5) samples.
1- serology
2- false positives, cross-reactions
3- coccidioidomycosis
4- IgM, IgG
5- urine, blood, CSF (Note- hypersensitivity skin tests, like PPD, can be performed)
list the 2 histoplasma capsulatum species and compare them by:
- infection type
- geographic location
- morphological features
H. capsulatum var capsulatum:
- pulmonary, disseminated infections
- eastern US, Latin America
- thinner cell walls, smaller size
H. capsulatum var duboisii:
- skin, bone lesions
- tropical Africa (African histoplasmosis)
- thicker cell walls, larger size
Histoplasma capsulatum is found in (1) in the environment, and the (2) parts can be aerolized and inhaled. (3) are some of the common locations for outbreaks.
1- high nitrogen content soil (bird/bat poop)
2- microconidia, hyphae
3- birds roost areas, caves, old buildings, construction/demolition areas
The clinical features of histoplasmosis depends on (1) and (2). Most result in (3) and a smaller portion develop (4) which can develop a (5) complication.
1- level of exposure (intensity, length of exposure)
2- immunological status
3- asymptomatic (low intensity exposure)
4- fever, cough, chest pain (high intensity exposure)
5- dissemination
list the 4 features on histology that confirm histoplasma capsulatum infection
-*inside alveolar macrophages
- unencapsulated
- thick walls
- budding yeasts
Blastomyces dermatitidis is found in (1) and outbreaks are related to (2). Most infections are reported in (3) geographic regions, specifically (4) areas.
1- decaying organic matter
2- contact with soil
3- middle and eastern North America
4- SE, Southern states bordering Mississippi and Ohio River basins + Midwest states / Canadian provinces bordering Great Lakes
______ is the main histological features of Blastomyces dermatitidis
single broad base bud in a yeast
Coccidioides immitis causes (1- include all names) and is transmitted through (2) mainly in (3) conditions and popular in (4) geographic areas.
1- conccidiodomycosis, Valley Fever
2- inhalation of arthroconidia in soil
3- late summer / early fall + dusty conditions
4- deserts in SW USA, northern Mexico (some areas of Central and South America)
Coccidiodomycosis is caused by (1) in California, (2) outside of California.
1- C. immitis
2- C. posadasii
Coccidioides immitis has (1) as the main histological feature and it contains (2). The purpose of (1) is for (3).
1- spherule (20-150 µm)
2- many spores (1-5 µm)
3- protects spores from phagocytosis
Most coccidioides immitis infections result in (1) because of (2). The rest of the infections result in (3) and can have (4) complications.
1- asymptomatic, 60% (primary coccidioidomycosis)
2- inhalation of few conidia
3- self-limited flu-like illness, 40%
4- progression to secondary form or dissemination
(1) and (2) are the key differences between primary and opportunistic fungal RTIs (in terms of opportunistic fungi)
1- affect immunocompromised mainly (usually not in healthy people)
2- monomorphic
(1) is the only encapsulated yeast. It is usually found in (2) and transmitted via (3).
1- Cryptococcus neoformans
2- pigeon droppings
3- inhalation of yeasts
Cryptococcus neoformans:
- common infection in (1) patients in (2) status
- (3) and (4) are the main differentiating histological feature
1- AIDS/HIV (+ sarcoidosis, liver disease)
2- CD4+ <100 cells/µL (>200 => oral thrush only)
3- narrow base budding yeast
4- encapsulated
Inhalation of cryptococcus neoformans triggers it to (1), which is made out of (2).
It also has a strong affinity for (3) which can cause (4).
1- capsule production
2- GXM, glucuronoxylomannan
3- CNS, neurotropic
4- meningitis
(1) fungi lacks ergosterol in its cell wall, and has (2) instead. It most commonly infects (3) patients with (4) status. (5) are evident on histology.
1- Pneumocytis jirovecii (=> pnemocystosis, PCP)
2- cholesterol
3- HIV/AIDS
4- CD4+ <100 cells/µL
5- interstitial infiltrates –> mononuclear infiltrates, mostly plasma cells [cyst in lungs]
Pneumocytis pneumonia:
- (1) classical symptoms
- 3% of infections result in (2)
- (3) is the hallmark of PCP
1- progressive dyspnea, nonproductive cough, fever (days-wks)
2- extrapulmonary lesions (lymph nodes, spleen, liver, bone marrow)
3- interstitial pneumonitis w/ mononuclear infiltrates (plasma cells) [cysts in lungs]
Aspergillus spp.:
- (1) are the relevant species
- normally found in (2)
- (3) is the main histological feature
1- fumigatus, flavus, niger
2- decaying organic matter, air, soil
3- acute angle septal hyphae
list the major forms of Aspergillosis (indicate the form found in immunocompromised patients)
- allergic
- aspergilloma / fungus ball
- invasive (acute, subacute) **found in immunocompromised
what are the features of Allergic Aspergillosis
- allergic rhinosinusitis (allergic bronchopulmonary aspergillosis / ABPA)
- hypersensitivity reaction: asthma, CF
what are the features of Aspergilloma
(fungus ball)
colonization of pre-existing lung cavity OR maxillary sinus
what are the features of Invasive Aspergillosis
- (high/low) mortality
- invasive part of fungus
- affected people
- Sxs
- Dx
- high mortality disease
- hyphae invades tissues: lungs mostly, sinuses, brain
- mostly lung transplant Pts, neutropenia, AIDS
- Sxs: fever, chest pain, hemoptysis, cough, SOB
- Dx: CT preferred, appears as bronchopneumonia, angioinvasive, tracheobronchitis, chronic necrotizing aspergillosis
