True Fungal Pathogens

Question 1

valley fever

Answer 1

coccidioidomycosis

Question 2

all 3 deep fungal pathogens are

what form in the env? host?

Answer 2

dimorphic, thermally regulated
MOLDS in the environment
Hc/Bd are YEAST in host
Co is an endosporulating spherule

Question 3

infection occurs via which route (all 3)? primary site of infection?

Answer 3

respiratory (inhale molds)

lung, may localize or disseminate

Question 4

dissemination may result in

Answer 4

dermologic manifestations

Question 5

while these are true pathogens, immunocompromise associated with?

Answer 5

greater incidence/severity of infection

Question 6

which is associated with persistent, clinically inactive infection and potential for reactivation, and acute primary infections (like TB)

Answer 6

Histo

Question 7

moist, high nitrogen soil, guano from birds and bats (caves)

Answer 7

histo

Question 8

mississippi and ohio river valley; midwest and south

Answer 8

histo

Question 9

latin america, africa

Answer 9

histo

Question 10

most common fungal infection in the world, most common systemic mycosis in US

Answer 10

histo

most commonly isolated cases

Question 11

TB CxR signs in PPD negative pts?

Answer 11

think histo

Question 12

histo morphology in environment? host?

Answer 12

multinucleate branched hyphae

uninucleate oval budding yeast w/narrow neck; inside MN phagocytes and extracellularly

Question 13

histo converts to pathogenic yeast form in host and multiplies where?

Answer 13

w/in macrophages

Question 14

immune response to histo

Answer 14

containment via CD4 T-mediated activation of MP’s –> fungistatic (restricted replication)

MP’s presnt antigen to T’s –> T’s secrete cytokines that activate MP’s agains Hc

Question 15

histo syndromes

Answer 15

pulmonary (emphysema pts)
disseminated (sites w/ lots of MN phagocytes)
mucocutaneous
ocular (abnormal neovascularization)
pericarditis

Question 16

CMI defects that lead to inc risk

Answer 16

AIDS, cancer, chemo
anti-TNF
age extremes

Question 17

fulfills one of the early AIDS criteria

Answer 17

histo, coccidio

Question 18

Histo tx

Answer 18

DOC for severe: AmphoB IV

Itraconazole for less severe, after resolution of acute sx in immunocompromised, and prophylaxis in immunocompromised

Question 19

prominent dog issue

Answer 19

blastomyces dermatitidis

Question 20

decaying vegetation or rich soil with ACIDIC pH by rivers

Answer 20

Blasto

Question 21

africa, mississippi, ohio river valleys, missouri river basin
N. MIDWEST (WI, MN)

Answer 21

Blasto

Question 22

blasto morphology in env? host?

Answer 22

hyphae twd uninucleate microconidia

host: multinucleate large budding yeast

Question 23

common clinical presentations include chronic cutaneous and osseous (disseminated) disease

Answer 23

blasto

Question 24

most common sites of dissemination are skin,bone, UG tract

Answer 24

blasto

Question 25

Blasto tx

Answer 25

ampho B itraconazole in immunocompetent and less severe in immunocompromised no prophylaxis (not high enough incidence in AIDS)

Question 26

california isolates

Answer 26

C. immitis

Question 27

non-california isolates

Answer 27

C. posadasii

Question 28

most severe of the 3 pathogens

Answer 28

coccidioides

Question 29

laboratory-acquired infection

Answer 29

coccidio

Question 30

central/south america | cali, arizona, texas

Answer 30

coccidio

Question 31

coccidia morphology env? host?

Answer 31

env: septate hyphae --> arthroconidia separated by VACUOLATED non-viable cells host: spherule containing endospores

Question 32

late summer and early fall incidence, esp when dusty conditions, rainy winter, soil disruption (earthquake)

Answer 32

coccidio

Question 33

cough, fever, chest pain, night sweats, joint pains

Answer 33

coccidio

Question 34

frequent sites of coccidio dissemination

Answer 34

meninges, bone, skin

Question 35

coccidio tx

Answer 35

immcompetent: amphB, fluconazole, itraconazole not completely effective more recalcitrant to antifungal tx than other 2

Question 36

dx of systemic dimorphic fungal pathogens

Answer 36

gold std: culture (high spec, low sens, slow) histo: note great but + clinical + failure to respond to abx serology: sensitivity depends on host immune response

Question 37

test for acute disseminated histo?

Answer 37

antigen detection: urine/serum/CSF

Question 38

skin testing

Answer 38

only for histo | histoplasmin

Question 39

general SDFP tx

Answer 39

mod/severe: amphoB | mild: itraconazole

Question 40

prevention

Answer 40

PPE formalin/bleach prophylactic antifungals: azoles for pts with deficient CMI, especially in endemic areas

Question 41

are any of these 3 contagious?

Answer 41

no

Question 42

roofer, farmer, gardener, demolition, chimney, bridge, roofer, spelunker

Answer 42

histo

Question 43

hard to see in sputum due to deep intracellular location in the lungs

Answer 43

histo | can see blasto, though

Question 44

early skin manifestations due to dissemination of fungal antigens, not infection (erythematous/macular-papular rash/nodosum/multiforme) hypersensitivity rxns

Answer 44

coccidio

Question 45

males and pregnant women at increased risk

Answer 45

coccidio

Question 46

intracellular smaller yeast on histology

Answer 46

histo

Question 47

greatest sensitivity for testing

Answer 47

urine

Question 48

liposomal amphoB

Answer 48

``` reduced nephrotoxicity (liver clearance) MP uptake in liver may target IC pathogens (HISTO) ```

Question 49

how does histo differ from TB?

Answer 49

not contagious | myco is bacteria, histo is fungus