Microbio: Mycology

Question 1

what disease do systemic mycoses cause?

Answer 1

all can cause pneumonia

Question 2

what is a dimorphic fungus?

Answer 2

cold: mold and heat: yeast.

cold is about 20 degrees and heat is 37 degrees or body temperature

Question 3

which fungi us not the normal dimorphic fungi?

Answer 3

cocciodiomycosis, which is a spherule at 37 degrees and not yeast.

Question 4

how to treat a local fungal infection

Answer 4

fluconazole or itraconazole

Question 5

how to treat a systemic fungal infection?

Answer 5

amphotericin B

Question 6

what makes fungal infections different from TB

Answer 6

can mimic TB but mycoses have NO transmission from person to person

Question 7

Histoplasmosis findings

Answer 7

found in the ohio and mississippi river valleys
causes pneumonia
macrophage filled with histoplasma (smaller than a RBC).

Question 8

what environmental feature leads to histoplasmosis

Answer 8

bird or bat droppings

Question 9

blastomycosis regional distirbution

Answer 9

east of mississippi river and central america

Question 10

blastomycosis disease

Answer 10

causes inflammatory lung disease that can disseminate to the bone and lung. forms granulomatous nodules. broad base budding (about the size of a RBC)

Question 11

Coccidiodomycosis geography

Answer 11

southwestern US and California

Question 12

diseases caused by cocciodiomycosis

Answer 12

meningitis and pneumonia. can disseminate to the bone and skin.

Question 13

what environmental things can increase cocciodiomycosis infections?

Answer 13

increased infections after earthquakes because spores in dust are thrown up into the air and become spherules in the lungs.

Question 14

spherules in cocciodiomycosis

Answer 14

these are seen at body temperature instead of the usual yeast. shperules are filled with endospores and are much larger than a RBC

Question 15

what do “desert bumps” refer to

Answer 15

erythema nodosum secondary to cocciodomycosis infection

Question 16

what does “desert rheumatism” refer to

Answer 16

cocciodiomycosis infection causing arthalgias

Question 17

paracocciodiomycosis geography

Answer 17

Latin America

Question 18

paracocciodiomycosis findings

Answer 18

budding yeast with a “captains wheel” formation. much larger than a RBC

Question 19

example of a cutaneous mycoses

Answer 19

tinea versicolor

Question 20

tinea versicolor

Answer 20

caused by infection with Malassezia furfur. degranulation of lipids produces acids that damage melanocytes and cause hypopigmented and or hyperpigmented patches.

Question 21

where does tinea versicolor normally happen

Answer 21

occurs in hot, humid weather.

Question 22

treatment for tinea versicolor

Answer 22

topical mconazole and selenium silfude (selsun)

Question 23

classic histology picture of tinea versicolor

Answer 23

spaghetti and meatballs

Question 24

tinea pedis infects the…

Answer 24

foot

Question 25

tinea cruris infects the...

Answer 25

groin

Question 26

tinea corporis... is

Answer 26

ringworm

Question 27

tinea capatis infects the...

Answer 27

scalp and head

Question 28

tinea unguium infects the....

Answer 28

onychomycosis on fingernails

Question 29

pruritic skin lesion with central clearing that produces a ring...

Answer 29

infection with dermatophytes. this includes Microsporum, trichophyton and epidermophyton.

Question 30

diagnostic test for dermatophytes

Answer 30

see mold hyphae in KOH prep. not dimorphic

Question 31

Candida albicans

Answer 31

can cause a superficial or systemic fungal infection, often in immunocompromised people. dimorphic yeast- can go from a yeast in a little circle to pseudohyphae or regular hyphae with environmental changes.

Question 32

candida albicans dimorphis

Answer 32

it appears that both yeast and pseudo hyphae can be seen at 20 degrees although there can be switching based on environment

Question 33

infections caused by candida albicans

Answer 33

1) oral and esophageal thrush (immune compromised) 2) vulvovaginitis (diabetics, abx use) 3) diaper rash 4) endocarditis in IV drug users 5) disseminated candidiasis 6) chronic mucocutaneous candiasis

Question 34

treatment for vaginal candidiasis

Answer 34

azole

Question 35

treatment for oral/esophageal candidiasis

Answer 35

fluconazole or caspofungin

Question 36

treatment for systemic candidiasis

Answer 36

fluconazole, amphotericin B or caspofungin

Question 37

feature known to be aspergillus

Answer 37

branching at 45 degree angles. septae hyphae that branch. can also see these conidiophores with radiating chains of spores. acute angles= aspergillus

Question 38

is aspergillus dimorphic

Answer 38

NO

Question 39

infections caused by aspergillus

Answer 39

invasive aspergillus (immune compromised) allergic bronchopulmonary aspergillus - associated with asthma and CF can be seen in the lungs after TB infection

Question 40

toxins produced by aspergillus

Answer 40

some forms of aspergillus produce afflotoxins which are associated with hepatocellular carcinoma.

Question 41

diseases caused by cryptococcus neoformans

Answer 41

cryptococcal meningitis and cyrptococcosis

Question 42

is cryptococcus neoformans dimorphic

Answer 42

NO

Question 43

where is cryptococcus neoformans found?

Answer 43

found in soil and pigeon droppings

Question 44

how does cryptococcus cause meningitis

Answer 44

it is inhaled and then transmits hematogenously through blood to the meninges

Question 45

how to culture cryptococcus neoformans?

Answer 45

stain with india ink and grow up on Sabouraud agar. Can also stain with mucicarmine.

Question 46

how to detect infection with cryptococcus neoformans

Answer 46

latex agglutination test detects the polysaccharide capsular antigen

Question 47

what disease causes classic soap bubbles in the brain

Answer 47

cryptococcus neoformans

Question 48

in what conditions do you see an infection with mucor?

Answer 48

diabetic keto acidosis (DKA) and leukemia

Question 49

how does mucor move around the body?

Answer 49

fungi proliferate in blood vessel walls when there is excess glucose and ketones and then penetrate the cribiform plate and enter the brain

Question 50

what does mucor cause?

Answer 50

rhinocerebral and frontal lobe abscesses

Question 51

findings in a mucor patient (clinical)

Answer 51

headache, facial pain, black necrotic eschar on face, may have cranial nerve involvement.

Question 52

treatment for mucor infection

Answer 52

amphotericin B

Question 53

what disease does pneumocystis jirovecii cause?

Answer 53

causes pneumocystis pneumonia (PCP) a diffuse interstitial pneumonia

Question 54

is pneumocystis jirovecii a yeast or hyphae

Answer 54

yeast

Question 55

symptoms of infection with pneumocystis jirovecii

Answer 55

usually asymptomatic

Question 56

how is infection with pneumocystis jirovecii diagnosed?

Answer 56

diffuse, bilateral appearance on CXR. diagnosed specificlaly by lung biopsy or lavage. disc shaped yeast forms on methenamine silver stain of lung tissue.

Question 57

which patient population is very commonly infected with pneumocystis jirovecii?

Answer 57

HIV

Question 58

prophylaxis for pneumocystic jirovecii

Answer 58

dapsone and atovaquone. start prophylaxis when the CD4 count drops below <200 in HIV patients

Question 59

treatment for pneumocysits jirovecii infection

Answer 59

TMP-SMX, pentamidine

Question 60

organism that causes sporotrichosis

Answer 60

sporothrix schenckii

Question 61

is sporothrix schenckii dimorphic

Answer 61

YES

Question 62

shape and findings in sporothrix schenckii

Answer 62

cigar shaped, budding yeast that lives on vegetation.

Question 63

how are people infected with sporothrix schenckii

Answer 63

spores are traumatically introduced into the skin- typically by a thorn- rose gardener's disease. causes a local pustule or ulcer with nodules along draining lymphatics

Question 64

do people with sporothrix schenckii get systemic illness

Answer 64

rarely. mostly an ascending lymphangitis

Question 65

treatment for sporothrix schenckii

Answer 65

itraconazole or potassium iodide