Pathophysiology of Invasive Mycoses

Question 1

how are systemic mycoses usually acquired

Answer 1

from inhalation of molds or spores in soil (noncontagious)

Question 2

what patients do disseminated fungal infection occur in

Answer 2

compromised/suppressed imune systems

Question 3

what fungus causes Histoplasmosis

Answer 3

dimorphic fungus that grows as mold in soil: Histoplasma Capsulatum

Question 4

what fungal infection is associated with bird and bat droppings

Answer 4

histoplasmosis

Question 5

where is most diseases of histoplasmosis and blastomycosis found

Answer 5

along OH and MS river valley

Question 6

how does histoplasma capsulatum cause histoplasmosis

Answer 6

it is inhaled and germinates in the lungs and releases yeast that are engulfed by macrophages

Question 7

what impairment causes yeast to continue to disseminate and not be contained

Answer 7

immunity impairment

Question 8

manifestations of histoplasmosis

Answer 8

-can be asymptomatic
-pneumonia
-Disseminated (extrapulmonary) to the bone marrow

Question 9

what fungus causes Blastomycosis

Answer 9

dimorphic fungus Blastomyces dematitidis that grows as mold in nature and yeast in the body

Question 10

How is blastomycosis transmitted

Answer 10

nearly all infections acquired by inhalation of spores near recreational waters and woods

Question 11

manifestations of blastomycosis

Answer 11

-can be asymptomatic
-pneumonia (mild)
-Disseminated (extrapulmonary) to the skin causing verrucous and ulcerative skin lesions

Question 12

what is coccidioidomycosis and the fungus that causes it

Answer 12

Valley fever due to Coccidioides Immitis

Question 13

what patient population is at most risk for coccidioidomycosis

Answer 13

patients in the SW U.S. that have high exposure to outdoor dust

Question 14

how is coccidioidomycosis transmitted

Answer 14

spore inhalation (especially during dust storms)

Question 15

manifestations of coccidioidomycosis

Answer 15

-can be asymptomatic
-pneumonia (mild)

Question 16

what pathogen causes Cryptococcosis and where its found

Answer 16

Cryptococcus found in soil and pigeon droppings

Question 17

manifestations of Cryptococcosis

Answer 17

-pneumonia
-CNS involvement causing meningitis, encephalitis, and mass lesions (cryptococcoma)

Question 18

what is the most common cause of fungal sinusitis

Answer 18

aspergillus

Question 19

what is the bacteria most responsible for causing aspergillosis

Answer 19

A. fumigatus

Question 20

how is aspergillosis transmitted

Answer 20

inhalation of spores

Question 21

manifestations of aspergillosis

Answer 21

-invasive pulmonary where fungal balls (aspergilloma) occur in patients with pre-existing pulmonary cavities
-allergic bronchopulmonary aspergillosis (ABPA) that is a hypersensitivity reaction in asthma or cystic fibrosis patients
-disseminated (extrapulmonary) spreading from lungs to the brain

Question 22

what are the Candida funguses that cause candidiasis

Answer 22

C. albicans
C. glabrata
C. krusei
C. tropicalis

Question 23

where does Candida colonize

Answer 23

commensal yeasts of the skin, vagina, and GI tract

Question 24

how does Candida cause infection

Answer 24

acquired via GI tract, IV catheters, and invasion of mucocutaneous surfaces that suppresses microflora bacteria and contributes to overgrowth and ability to invade the bloodstream

Question 25

manifestations of candidiasis

Answer 25

-cutaneous/mucocutaneous causing thrush (dense painless yeast growth in moist areas of body)
-hematogenous (invasive) candidiasis
-candiduria (cystitis following catheterization or therapy with broad spectrum antibacterial)

Question 26

what is the source of hematogenous (invasive) candidiasis in healthy host

Answer 26

usual source of candidemia (blood infection) in IV lines

Question 27

what is the source of hematogenous (invasive) candidiasis in neutropenic and other compromised patients

Answer 27

source is frequently the gut