Fungal Infections Flashcards
1
Q
what are the means of which to dx fungal infections?
A
- potassium hydroxide (KOH)
- culture
- biopsy
2
Q
discuss the proper use KOH preparation
A
- rub alcohol to site
- use a #15 surgical blade & gently scrape
- if it scales, scrape it!
3
Q
azoles
- MOA
- include what drugs?
- clinical uses of each?
- AEs?
A
“azoles”
- MOA: demethylation of C14a in of lanasterol, a precursor of ergosteral (steroid in fungal cell walls)
- specific uses:
- fluconazole: all types of candida
- itraconazole: blasomyces, coccididiodes, histoplasma
- clotrimazole, miconazole: superficial fungal infections
- voriconazole, isavuconazole: asperilligus
- adverse effects (AE):
- gynocomastia
- impotence
- liver dysfunction
4
Q
which azole has the most severe AEs?
what are they?
A
ketoconazole
- gynecomastia
- impotence
- liver dysfunction
5
Q
terbinafine
- what kind of drug?
- MOA?
- have what clinical uses?
- have what adverse effects?
A
- includes: allyamine
- MOA: inhibits squalene epoxidase -> decreases ergosterol
- clinical uses:
- onchomycosis - nail fungus
-
tinea capitis adults - scalp fungus
- griseofulvin m/c used in children*
- adverse effects:
- GI upset
- liver abnormalities
- drug induced lupus
6
Q
griseofulvin
- MOA?
- have what clinical uses?
- have what adverse effects?
A
- MOA: disrupts microtubule formation → inhibiting mitosis
- clinical uses: TOC for tinea capitis in children
- adverse effects (AE): reduces efficacy of
- oral contraceptives
- warfarin
7
Q
polyenes
- includes what drugs?
- MOA?
- have what clinical uses?
- have what adverse effects?
A
- includes: nystatin, amphotericin B
- MOA: irreversibly finds to ergosterol -> increasing cell membrane permeability
- clinical uses:
-
nystatin: candida infections
- oral candidasis* “swish & swallow”*
- topical for diaper rash
- amphotericin B: serious systemic mycosis
-
nystatin: candida infections
- AEs (amphotericin B)
- NEPHROTOXICITY
- fever/chills + hypotension
8
Q
what does tinea look like on a KOH preparation?
A
branching, with septate hyphae
9
Q
tinea capitis
- definition
- demographics
- presentation:
- treatment:
A
- pathogenesis: dermatophyte infection scalp and beard
- endothrix: arthroconidia on nterior of hair shaft
- ectothrix: arthroconidia on exterior of hair shaft
- demographics: childhood, M > F
- presentation: scaling, pruritis, eventual -> loss of (hair)
- treatment:
- children: griseofulvin
- adults: terbinifine
10
Q
kerion
- pathogenesis
- demographics
- presentation
- complications
- treatment
A
- pathogenesis: tinea capitis that progresses into furuncle
- demographics: farm animal exposure
- presentation: furuncle = painful, boggy, puritic
- complications: may evolve into permanent alopecia so treat early!!
- treatment: steroids ( & griseofulvin?)
11
Q
tinea barbae
- pathogenesis
- demographics
- presentation
A
- demographics: rare - always ask about farm animal exposure
- presentation: unilateral involvement of the neck + face
12
Q
tinea faciei
- demographics
- presentation
- treatment
A
- demographics:
- female and children
- possible hx of animal exposure
- presentation:
- annular configuration + pustules in the border
- frequently on the upper lip + chin
13
Q
tinea corporis
- pathogenesis
- presentation
- treatment
A
- pathogenesis: dermatophyte (m/c T. rubum) infects the body/trunk
- presentation: plaques on body / trunk that are
- annular with central clearing
- scaly
- have advancing edge
- treatment: azoles
- localized - econazole, ketoconazole (topicals)
- extensive - fluconazole (oral)
14
Q
what can you NOT use to treat tinea corporis?
A
lotrisone
15
Q
tinea cruris
- demographics
- presentation
- treatment
A
- demographics: M>F
- presentation: plaques on groin, perineal & perianal skin that are
- party clear in center (but not annular w/ central clearing like corporis)
- scaly
- erythematous
- treatment:
- meds: azoles (like corporis)
- lifestyle: reduce perspiration / moisture + loose fitting clothing
19
Q
onchomycosis
- pathogenesis
- presentation
- diagnosis
- treatment
A
- pathogenesis: m/c T. rubum
- presentation: yellow discloration that spreads from distal → proximal
- eventual separation from nail bed
- subungual hyperkeratosis
- diagnosis: sabaroud agar
- treatment: terbinafine - esp for pts with
- DM
- perpireral neuropathy
21
Q
candidiasis:
- demographics:
- presentation:
- diagnosis
A
- demographics: I/C - DM, AIDS, on abx (esp in oral candidasis)
- presentation:
- oral: gray-white membranous plaques that bleed w/ scraping
- rash (interiginous / vulvovaginitis / diaper): beefy red plaques with satellite lesions + fisssuring
- diagnosis:
- at 20 C: psuedohyphae + budding yeast
- at 37 C: germ tubes
- sabraud’s agar: growth
- histopathology: vertically oriented psuedohyphae
22
Q
oral candidias (thrush)
- demographics
- presentation - gross & clinical
- treatment
A
- demographics:
- newborns - m/c
- in children/adults: after Abx course (I/C)
- in adults with no predisposing factors (no Abx, not I/C): may be first manifestation of AIDS - they need a workup!
- gross presentation: grayish white membranous plaques with red, moist, macerated base
- clinical: metallic taste +/- dysphagia / odynophagia (if esophageal extension, which is m/c in AIDs pts)
- treatment:
- infants: oral nyastatin suspension
- adults: oral nyastatin suspension OR fluconzole single dose 150 mg
23
Q
perleche (angular chelitis)
- pathogenesis:
- demographics
- presentation
A
- pathogenesis: C. albicans OR S. aureus
- if S. aureus, “honey colored crust” likely present
- demographics: elderly, due to:
- ill-fitting dentures
- exaggerated skin folds
- dry mouth
- presentation: oral commissures have ill-defined, grayish-white thickened areas with erythema (like thrush)
25
Q
paronchyia
- pathogenesis
- presentation
A
- pathogenesis: d/t C. albicans OR staph
- if acute = s. aureus
- if chronic = candida (c for candida)
- presentation: inflammation of nail-fold
27
Q
tinea versicolor
- pathogenesis
- presentation
- diagnosis
- treatment
A
- pathogenesis: malassezia globosa
- demographics: tropical demographic - esp summer months
- presentation: macules that are
- hyper OR hypo-pigmented
- on upper trunk
- scaly, non-blanching and -> coalescing
- diagnosis:
- KOH: short fungae + variably sized spores (“spaghetti and meatballs”)
- wood’s lamp: yellow-green
- treatment:
- topical: azoles OR selenium sulfied
- oralL: fluconazole
28
Q
identify
A
tinea versicolor (malassezia)
wood’s light examination: yellow-green flourescence
KOH prep: spaghetti and meatballs
31
Q
sporotrichosis
- pathogenesis
- presentation
- treatment
A
- pathognenesis: sporothrix schenkii:
- dimorphic, cigar shaped budding yeast
- branching hyphae with rosettes of conidia
- demographics: gardeners - it lives on vegetations
- presentation: ascending lymphangitis - nodules that form along draining lymphatics
- teatment: itraconazole
32
Q
identify
A
sporothrix schenckii - “rose gardeners rash”
dimorphic, cigar shaped yeast that grows into -> branching hyphae with rosettes of conidia
