Mycology

Question 1

yeast

Answer 1

candida albicans
cryptococcus neoformans
pneumocystis jirovecii (PCP)

Question 2

candidal esophagitis

Answer 2

AIDs, leukemia, lymphoma
sx:
painful swallowing
substernal chest pain
feeling of obstruction when swallowing

DDx: CMV, herpes esophagitis

Question 3

oral thrush

Answer 3

neonates
steroids
diabetes AIDS
DDx: oral hairy leukoplakia

Question 4

candidal vulvovaginitis

Answer 4

diabetic patients, women with recent antibiotic use
sx: 
severe itching
edema
vaginal discharge
acidic pH

Question 5

candida albicans diaper rash

Answer 5

jagged edges, satellite lesions

Question 6

candical intertrigo

Answer 6

erythematous central lesions with satellite lesions

Question 7

candida bloodstream infections

Answer 7

central lines
drug users
cancer patients
transplant patients

leading to endophthalmitis, endocarditis

Question 8

chronic mucocutaneous candidiiasis

Answer 8

mucous membranes, hair, nails

Question 9

candida albicans diagnosis

Answer 9

blood culture

germ tubes- small projections on side of cell, usually within 90 minutes

Question 10

treatment for candida albicans

Answer 10

superficial infections: nystatin, clotrimazole, fluconazole

systemic infections:
fluconazole, amphotericin B, echinocandin

Question 11

cryptococcal meningitis

Answer 11

AIDS

Question 12

cryptococcus- wide or narrow? where is it found? what can you use to culture it? what can you use to stain it?
is there a serological test?
what does it look like on imaging?

Answer 12

heavily encapsulated yeast, reproduces by narrow- based budding
soil and pigeon droppings
can be cultured on most bacterial and fungal media
often cultured on Sabouraud’s agar

stain with India ink

serological test for cryptococcal antigen is more sensitive than India ink

latex agglutination test to detect polysaccharide capsular antigen

“soap bubble” lesion on imaging

Question 13

How to treat cryptococcus

Answer 13

amphotericin B + flucytosine

followed by fluconazole

Question 14

PCP PNA
what stain?
what does it look like on imaging?

Answer 14

atypical
diffuse interstitial PNA that developed into potentially fatal PNA in immunocompromised patients

Dx: silver stain
imaging- ground glass appearance of interstitial infiltrates

Question 15

PCP PNA treatment

Answer 15

TMP-SMX (begin with IV, transition to oral)

sulfa allergy: pentamidine, clindamycin + primaquine

ppx when CD4

Question 16

Molds

Answer 16

Aspergillus fumigatus
mucor
rhizopus

Question 17

Aspergillus fumigatus

Answer 17

allergic bronchopulmonary aspergillosis

fungus ball (aspergilloma)
invasive aspergillosis

Question 18

where is aspergillus found

Answer 18

ubiquitous

soil, air, water, food

Question 19

what does it look like?

Answer 19

narrow septate hyphae that branch at acute angles (45 degrees)

Question 20

aspergillus treatment

Answer 20

voriconazole

lipid formulation of amphotericin B

Question 21

Mucor and Rhizopus

where are they found? who gets infected? what do they look like?

Answer 21

cause mucormycosis
ubiquitous
invasive disease in severely immunocompromised, trauma patients, diabetics

broad, irregularly shaped, nonseptate hyphae branching at right angles

Question 22

patients with DM, DKA, leukemia, neutropenia, with mucormycosis

Answer 22

rhinocerebral mucormycosis
facial pain
HA

Mucor grows into vessel walls, leading to large necrotic lesions (look like eschar)

CN deficits, blindness
Dx: biopsy

Tx: surgical debridement, amphotericin B

Question 23

Dermatophytes

Answer 23

Trichophyton
Microsporum (dog or cat reservoir)
Epidermophyton
Malassezia furfur

Question 24

What infections are commonly caused by dermatophytes?

how do we diagnose?

Answer 24

tinea pedis (feet)
tinea cruris (groin)
tinea capitis (head)
tinea unguium (nails) aka onychomycosis

on the body it is called ringworm

diagnosis: fungal hyphae or spores on skin or hair samples

culture

Question 25

how to treat fungal skin infection

Answer 25

topical terbinafine or azole extensive skin infection or scalp/hair infection PO terbinafine or azole

Question 26

tinea unguium (nails) aka onychomycosis

Answer 26

trichophyton rubrum ``` thickened, discolored nails PO therapy recommended terbinafine itraconazole fluconazole treat for a year (fingernails clear faster than toenails) ```

Question 27

Malassezia furfur

Answer 27

hypopigmented patches. nonpruritic KOH prep: spaghetti and meatballs topical azole, selenium sulfide

Question 28

causes diaper rash

Answer 28

candida albicans

Question 29

opportunistic mold with septate hyphae that branch at a 45 degree angle

Answer 29

aspergillus

Question 30

opportunistic mold with irregular nonseptate hyphae that branch at wide angles (>90)

Answer 30

mucor, rhizopus

Question 31

causes thrush in immunocompromised patients and vulvovaginitis in months

Answer 31

candida albicans

Question 32

known for causing pneumonia in AIDS patients

Answer 32

PCP

Question 33

yeast known for causing meningitis in AIDS patients

Answer 33

cryptococcus meningitis

Question 34

dimorphic fungi

Answer 34

mold form at 20 degrees C yeast form at 37 degrees C cold mold, heat yeast

Question 35

systemic mycoses versus tb

Answer 35

both cause granulomas, however molds form non-caseating granulomas unlike TB

Question 36

what kind of agar for dimorphic fungi?

Answer 36

Sabourad agar

Question 37

Histoplasma capsulatum

Answer 37

Mississippi and Ohio river valleys in bird and bat guano on histology, you will see macrophage filled with histoplasma (smaller than RBC) histo hides within macrophages

Question 38

Blastomyces dermatitidis

Answer 38

states bordering Mississippi and Ohio river basins up to Canada Central America enters via pulmonary route causes pulmonary infection disseminates to the rest of the body skin, bone, granulomatous nodules

Question 39

coccidiodes immitis

Answer 39

Southwestern US. "San Joaquin Valley Fever" disease incidence may increase after sandstorms or earthquakes Mycelial (soil) and spherule forms arthroconidia (barrel shape) can become airborne and deposit themselves in the human lung The arthroconidia form spherules within the lung, which divide until the spherule becomes so packed with daughter cells that it bursts infections are often asymptomatic or mild severe PNA or disseminated disease - CNS (meningitis) - skin findings - bones - joints

Question 40

Paracoccidiodes brasiliensis

Answer 40

latin america is the only known endemic area enters through respiratory route disseminated progressive disease -severe PNA -granulomatous changes in mucous membranes and skin Captain's wheel appearance

Question 41

Sporothrix Schenckii

Answer 41

``` dimorphic fungus soil and vegetation often introduced by a thorn sphagnum moss nodules appear along the draining lymphatics (painless) ``` no systemic sx Tx: itraconazole potassium iodide

Question 42

found in SW US including west Texas and California

Answer 42

coccidioides immitis

Question 43

found in Mississippi and Ohio River basins

Answer 43

histoplasma capsulatum

Question 44

causes San Joaquin Valley fever

Answer 44

coccidioides immitis

Question 45

found in rural Latin America

Answer 45

paracoccidioides brasiliensis

Question 46

associated with plant thorns and cutaneous injury

Answer 46

Sporothrix schecnkii

Question 47

found in states east of the Mississippi River

Answer 47

blastomyces dermatitidis

Question 48

found in bird and bat droppings

Answer 48

histoplasma capsulatum

Question 49

mold form contains barrel- shaped arthroconidia

Answer 49

coccidioides immitis

Question 50

associated with dust storms

Answer 50

coccidioides immitis

Question 51

broad- based budding of yeast

Answer 51

blastomyces dermatitidis

Question 52

multiple budding of yeast form

Answer 52

paracoccidioides brasiliensis (captain's wheel)