Fungi

Question 1

What is the unicellular growth form of fungi? how do they reproduce?

Answer 1

yeast- budding

Question 2

What is it called when yeast cell buds do not separate

Answer 2

pseudohyphae

Question 3

What are hyphae

Answer 3

threadlike branching, cylindrical tubules of fungal cells attached end by end

Question 4

What are molds

Answer 4

mycelia
multicellular colonies of clumped hyphae
produce spores

Question 5

what are dimorphic fungi

Answer 5

fungi that grow as either yeast or mold depending on environment and temperature

Question 6

What are Saprophytes

Answer 6

fungi that live in and utilize organic matter as energy source

Question 7

Describe the innermost layer of fungi

Answer 7

cell membrane that is bilayer and has lots of sterols- ergosterol

Question 8

How do most antifungals work

Answer 8

disrupting ergosterol
like amphotericin B and nystatin
or ergosterol syntehsis- azoles

Question 9

What component of fungi are strong Ag to human immune system

Answer 9

the Cell wall

Question 10

What stain do you use to visualize the capsule of fungi

Answer 10

India ink stain

Question 11

What are the superficial fungal infections

Answer 11

pityriasis versicolor and tinea nigra

Question 12

what is presentation of pityriasis versicolor

Answer 12

hypo and hyper pigmented patches on the skin

caused by Malassezia furfur

Question 13

What is the presentation of tinea nigra

Answer 13

causes dark brown black painless patches on soles of hands and feet
caused by exophiala werneckii

Question 14

How do you Dx tinea nigra or pityriasis versicolor

Answer 14

skins crapings mied with KOH will reveal hyphae and spherical yeast

Question 15

What is the best Tx for superficial fungal diseases

Answer 15

dandruff shampoo that has selenium sulfate

Question 16

what fungi cause cutaneous fungal infections

Answer 16

dermatophytes

Question 17

What enzyme do dermatophytes secrete

Answer 17

keratinase

Question 18

What are the most common dermatophytes

Answer 18

Microsporum, Trichophyton and Epidermophyton

Question 19

presentation of tinea corporis

Answer 19

ring with red raised border
areas of active inflammation and area of healing in middle
ring worm

Question 20

What is tinea cruris

Answer 20

jock itch

itchy red patches on groin and scrotum

Question 21

what is tinea pedis

Answer 21

athletes foot

cracking and peeling of skin between toes

Question 22

what is tinea capitis

Answer 22

scaly red lesions with loss of hair on scalp

Question 23

what is tinea unguium

Answer 23

thickened nails that are discolored and brittle

onychomycosis

Question 24

What do you use to Dx microsporum

Answer 24

direct examination of hair and skin with Woods light

will fluoresce green

Question 25

What does candida albicans cause

Answer 25

oral thrush, diaper rash and vaginitis

Question 26

how do subcut fungal infections gain entrance

Answer 26

trauma to the skin

Question 27

What causes sporptichosis

Answer 27

sporothrix schenckii

Question 28

Presentation of sporothrichosis

Answer 28

subcut nodule that becomes necrotic and ulcerates follows lymph tracts yeast at 37 C hyphae at 25C

Question 29

What is quick cheap Tx for sporothrichosis

Answer 29

Potassium iodide

Question 30

What is chromoblastomycosis? what cause it

Answer 30

subcut infection caused by variety of copper-colored soil saprophytes found on rotting wood Phialophora and Cladosporium

Question 31

Presentation of chromoblastomycosis

Answer 31

small violet wartlike lesion that over mo-yrs many arise nearby, look like cauliflower

Question 32

How do you Dx chromoblastomycosis

Answer 32

KOH reveal copper-colored sclerotic bodies

Question 33

What fungi cause systemic disease in humans

Answer 33

Histoplasma capsulatum, Blastomyces dermatidis, Coccidioides immitis

Question 34

Describe characteristics of the fungi that cause systemic disease

Answer 34

dimorphic mycelial forms with spores at 25 C yeast form at 37 C

Question 35

Where are Histoplasma and Bastomyces endemics

Answer 35

Mississippi River area

Question 36

Where is Coccidioides endemic

Answer 36

Arizona and old southwestern areas

Question 37

AIDS patient with opportunistic infection that previously lived in Arizona. most likley Dx?

Answer 37

Coccidioides

Question 38

What are the 3 clinical presentations of the systemic fungi

Answer 38

asymptomatic pneumonia- like TB disseminated- rare

Question 39

What is the best way to Dx systemic fungi

Answer 39

biopsy of affected tissue silver stain NOT PPD type because many people have been exposed

Question 40

What is different of systemic fungal infections vs TB

Answer 40

not person to person transmission | fungi have spores, not acid fast

Question 41

What is Histoplasma capsulatum assoc with

Answer 41

exposure to bat and bird droppings | cleaning chiken coops or spelunking

Question 42

What is presentation of Blastomyces dermatitidis

Answer 42

weight loss, night sweats, lung involvement and skin ulcers

Question 43

What type of fungi is Cryptococcus

Answer 43

polysaccharide encapsulated yeast, not dimorphic

Question 44

What is the major manifestation of cryptococcus infection

Answer 44

meningoencephalitis

Question 45

Where is cryptococcus neoformans found? what population does it infect?

Answer 45

pigeon poop | AIDS paitents- 10%

Question 46

What is the risk of cryptococcal meningitis without Tx

Answer 46

death from cerebral edema and brainstem compression

Question 47

What is the Dx for cryptococcus infection

Answer 47

lumbar puncture and CSF analysis

Question 48

What does the India ink stain of cryptococcus look like

Answer 48

halo of polyscarrachride capsule around yeast cells

Question 49

What is the most sensitive/confirmatory cryptococcal lab

Answer 49

cryptococcal Ag test

Question 50

What are the 3 cutaneous infections caused by Candida

Answer 50

oral thrush- creamy white exudate Vaginitis- cottage cheese diaper rash- red and macerated

Question 51

What can candida cause in immunocompromised host

Answer 51

esophagitis- burning substernal pain worse with swallowing disseminated- every organ see white fluffy candidal patches in retina

Question 52

What is the clinical pearl of candida detection in samples

Answer 52

normal in urine, stool and sputum | abnormal in blood!!!! immunocompromised

Question 53

What 3 types of diseases are caused by Aspergillus

Answer 53

Allergic Bronchopulmonary Aspergillosis (ABPA) infection in preformed lung cavities "Aspergilloma" invasive infection of lung "invasive aspergillosis"

Question 54

What type of reaction is ABPA

Answer 54

type 1 HS reaction IgE mediated with bronchospasm blood eosinphilia also type 4 DTH with cell mediated inflammation and lung infiltrates

Question 55

What is an aspergilloma

Answer 55

lung cavitations from TB or malignancies that grow aspergillus fungal ball in cavity

Question 56

What is Tx for aspergilloma

Answer 56

surgical excision

Question 57

What is presentation of invasive aspergillosus

Answer 57

slowly progressive asymptomatic pneumonia, multiple nodular infiltrates high mortality rate

Question 58

What toxin does aspergillus secrete? where is it most prominent?

Answer 58

Aflatoxin | peanuts grains and rice in sahara desert in Africa

Question 59

What patients are at highest risk for mucormycosis infection

Answer 59

profound acidotic patients like diabetics, immunocompromised, burn patients or those taking iron chelator deferox-amine

Question 60

What areas do the mucormycosis fungi infect

Answer 60

sinuses, cranial bones and blood vessels

Question 61

What are the fungi like bacteria

Answer 61

Actinomycetes and Nocardia

Question 62

What is important about Actinomycetes

Answer 62

``` gram + filamentous beaded anaerobe normal flora eroding abscesses sulfur granules treat with Penicillin ```

Question 63

What is important about Nocardia

Answer 63

gram + beaded filamentous ACID FAST not normal flora misDx as TB alot Tx with sulfamethoxazole