w21 systemic mycoses Flashcards
LO
EXTRA READING MURRAYS CHAP64
- Classify types of systemic fungal infection and associated
geographic distributions - Knowledge of modes of transmissions
- Describe different virulence factors & clinical signs
- Understand diagnosis methods
- Aware of different treatment options
What are dimorphic fungal pathogens and how does their form change in nature , in tissues or when grown on enrinched medium
organisms in mold form in nature or lab at 25-30”
tissues & medium - yeast & spherule form
Why are they considered primary systemic pathogens
ability to cause infection in norm and immunocomp. hosts & propensity to inv. deep viscera after dissemination of fungus from lungs after inhalation from nature
Name the 4 endemic dimorphic fungal infections
Blastomycosis
Histoplasmosis
Coccidioidomycosis
Paracoccidioidomycosis
Name the 4 endemic dimorphic fungi pathogens
Blastomyces dermatitidis
Histoplasma capsulatum
Coccidioides immitis
Paracoccidioides brasiliensis
Why are the organisms endemic pathogens
their natural habitat is delimintaed to specific geo.regions and infection of specific type is caused by inhalation of spores from specifc envt and geo.location
What does the circumstance of DE fungal disease development depend on
dose
immune status
is the diseased person infectious from dimorphic endemic fungi
no
What regions is blastomycosis seen in most
in Ohio, Mississipi River , SE USA , Africa
What kind of habitat does blastomyces dermatitidis originate from
soil & organic debris
Describe the mode of infection for blastomyces dermatitidis
conidia inhalation (99%)
conidia inoculation (1%)
NO P2P TMission
1-2 cases/100,000 ppl/yr
Describe BDermatitidis at saprobic and parasitic phase
saprobic phase (25’C) - septate mycelium and conidium (bud head and long thin poles)
Parasitic (37’) yeast form seen in tissue
- thick db countoured wall & large braod based budding yeast.
Describe the pathogenesis of BDermatitidis
inhaled conidia convert to yeast
host invasion»_space;inflammation
yeast escapes recog. by MpH & may disseminate via blood
chronic,suppurative & granulomatous inflam. in chronic cases
Name the virulence factors related to BDermatiditis
grow @ 37’C
dimorphism
- BAD-1 adhesin promos yeast bidning to MpHs (CR3, CD14,)
- BAD-1 expression by yeasts = supresses expression of TNF-alpha pro-inflamm. cytokine
- high alpha (1-3)-glucan on cwalls assoc. w virulence
How many ppl infected w blastomycosis show symptoms
less than half
Name 4 Clinical forms of blastomycosis
primary pumonary Bycosis
Advanced pulmonary disease
Primary skin lesion
Disseminated Bycosis
Primary pulmonary blastomycosis is a ___ - like illness
flu-like ; mild and difficult to diagnose
Advncd pulmonary disease ocassionally develops & resembles ______ and related symptoms such as ____..
tuberculosis ; high fever, cough, lobar infiltrates
An uncommon clinical form of blastomycosis is
primary skin lesion
Disseminated Bmycosis
chronic cutaneous ; result of haematogenous dissemination from the lung (pulmonary lesions or systemic symptoms absent)
- bone, prostate and liver , GIT
Name symptoms of chronic pulmonary Bmycosis
anorexia
weight loss
cough
Haemoptysis
Night sweating
- cutaneous ulcerating bmycosis (on skin)
- osteomyelitis occurs in long bones of extermities
alts in both lungs (x ray)
CASE EXAMPLE SLIDE
