Fungal Infections Flashcards
very common dimorphic yeast that has the ability to undergo transformation to hyphal form under appropriate conditions, producing germinative or “germ” tubes
candida albicans
yeast form of candida albicans
commensal
hyphal form of candida albicans
pathogen
whether candidiasis develops, and the severity of the disease itself, appears to depend on at least what three factors?
- host immune status
- oral mucosal environment
- virulence of the candidal strain
what is the spectrum of the candida disease?
- “carrier” state
- superficial oral mucosal/cutaneous infection
- localized invasive candidiasis
- disseminated candidiasis
*last two are uncommon
what are the three presentations of oral candidiasis
- pseudomembranous
- erythematus
- hyperplastic
type of candidiasis that is known as “thrush” that is whic, curled milk or cottage cheese-like plaques that CAN BE WIPED OFF
pseudomembranous candidiasis
what are the common sites of pseudomembranous candidiasis
- buccal mucosa
- palate
- tongue
type of candidiasis that has an area of redness, variable borders
erythematus candadiasis
*tongue is a common site
diffuse atrophy of dorsal tongue papillae, particularly after broad spectrum antibiotics
acute atrophic candadiasis (antibiotic sore mouth)
typically associated with “burning” sensation
acute atrophic candadiasis
well-defined area of redness in mid-posterior dorsal tongue that is usually asymptomatic
central pappillary atrophy
median rhomboid glossitis in the past
what is central papillary atrophy most commonly due to?
chronic candadiasis
denture is often contaminated with candidal organisms but NO invasion of mucosa is seen. shows erythema of palatal denture-bearing area - typically asymptomatic
denture stomatitis
(chronic atrophc candidiasis)
*found many colonies on antaglio surface of denture but NONE on the mucosal surface
redness, cracking corners of the mouth that often waxes and wanes
angular chelitis
what causes angular chelitis
usually related to candadiasis but may have other cutaneous bacterial microflora admixed
how do you tx angular chelitis?
typically responds well to topical antifungal therapy
redness, cracking of thte cutaneous surface that is often associated with lip-licking or chronic use of petrolatum-based materials
perioral candidiasis
what causes perioral candadiasis?
lip-licking
-usually related to candidiasis, but may have other cutaneous bacterial microflora admixed
how do you treat perioral candidiasis
topical antifunal therapy
when the pt has angular chelitis central papillary atrophy and a “kissing lesion” of the posterior hard palate
chronic multifacial candidiasis
also known as “candidal leukoplakia” that has white patches that CANNOT be rubbed off. may be problematic because a true leukoplakia may have candidiasis
hyperplastic candidiasis
where is hyperplasitc candidiasis usually found?
generally anterior buccal mucosa
what is the tx for hyperplatic candidiasis?
antifungal therapy
RARE candidal infection associated with specific immunologic defects related to how the body interacts with candida albicans
chronic mucocutaneous candidiasis
RARE candidal infection seen in situations of severe uncontrolled diabetes mellitus or immune supression
invasive candidiasis
what are some histological features of candidiasis?
- microabscesses may be seen in the superficial epithelium
- chronic inflammation of the connective tissue
- acanthosis is often present
in almost all cases, candidal hyphae never penetrate deeper than what layer?
keratin layer
the prognosis for treating oral candidiasis in normal pts is what?
good
the prognosis for treating oral candidiasis in immune suppressed pts is what?
fair to poor
what does candidiasis tx depend on?
severity of the infection
what can superficial oral mucosal infections usually be treated with?
one of the milder topical systemic antifungal angents
life threatening infections usually require what for treatment?
intravenous amphotericin B
imidazole antifungal agent with no significant absorption or side effects
clotrimazole (mycelex)
*pleasant tasting lozenges
what is the disadvantage to clotrimazole?
dosing schedule (should be dissolved in mouth 5 times per day)
antifungal developed during the 1950s that is NOT absorbed systemically and must be IN CONTACT with the organism in order to be effective
nystatin (mycostatin)
what is the disadvantage to nystatin
taste, bitter to many
-multiple dosing schedule, pt compliance
triazole antifungal angent that is readily absorbed SYSTEMICALLY and no significant degree of side effects
fluconazole (diflucan)
what are the disadvantages to fluconazole?
-relatively expensive
when do you use topical antifungal agents?
in treatment of angular cheilitis or perioral candadiasis
combination of nystatin and triamcinolone
mycolog II cream
combination of iodoquinol and hydrocodone
vytone cream
deep fungal infection that is endemic to ohio and mississippi river valleys
histoplasmosis
how many new cases of histoplasmosis are there annually?
500K
how is histoplasmosis spread?
spores in bat or bird droppings in the soil
most cases of histoplasmosis are what?
asymptomatic
what might acute histoplasmosis have?
flu-like symptoms
what might chronic histoplasmosis have?
cavitary pulmonary lesions
what populations are most likely affected by disseminated histoplasmosis?
- elderly
- debilitated
- immunocompromised
in what form of histoplasmosis are oral lesions uaually seen?
disseminated
*affects tongue, palate, and buccal mucosa
what do oral lesions of histoplasmosis look like?
chronic variably painful ulcer or granular erythematous plaque
clinically, oral lesions of histoplasmosis may be identical to what?
malignancy
histoplasmosis is what?
granulomatous inflammation with or without necrosis
how big are the yeast cells for histoplasmosis?
1-2 micron yeast, usually within macrophages
histoplasmosis is best visualized by what?
silver stain (GMS) or PAS)
what are the three ways to dx histoplasmosis?
- ID of characteristic yeasts in tissue sections
- culture of the H. capsulatum organism from a suspected lesion
- serologic testing for antibodies or yeast related antigens
what is the tx for acute histoplasmosis?
no tx necessary
what is the tx for chronic or disseminated histoplasmosis?
amphotericin B
*ketoconazole or itraconazole for mild cases or as maintenance therapy
what is the prognosis of tx ACUTE histoplasmosis in an immunocompromised pt?
good
what is the prognosis of tx CHRONIC histoplasmosis?
fair
what is the prognosis of tx DISSEMINATED histoplasmosis?
poor
*mortality rate of 90% if untreated, 7-23% if treated
deep fungal infection endemic to desert southwest US known as the hypersensitivity rx
coccidioidomycosis
how many ppl are infected with coccidioidomycosis annually?
100K
how is coccidioidomycosis transferred?
inhalation of spores
what is the illness like in 40% of coccidioidomycosis infected pts?
flu-like symtoms
dissemination of coccidioidomycosis occurs in how many pts?
less than 1%
where does infection of coccidioidomycosis usually occur on the human body?
skin of the central face may be affected, oral lesions are rarely described
how is the dx of coccidioidomycosis made?
culture or biopsy
what is the host response to coccidioidomycosis
ranges form acute to granulomatous infection
what is the tx for disseminated coccidioidomycosis?
amphotericin B
what is the tx for mild cases of coccidioidomycosis
fluconazole or itraconazole
coccidioidomycosis may be more aggressive in what population?
ppl of color
generally, coccidioidomycosis has a good prognosis if the pt….
is not immunocompromised
this deep fungal infection has organisms that liv in pigeon droppings and is treansmitted by air-borne sopores
cryptococcosis
cryptococcosis affects what population almost exclusively?
immunosuppressed
what are the clinical presentations of cryptococcosis?
- flu-like symptoms with initial pulmonary infection
- disseminates to meniges, resulting in headache, vomiting, neck stiffness
4-6 micon yeasts with a clear halo (representing a mucopolysaccharide capsule)
cryptococcosis
dx of cryptococcosis is based on what?
culture or ID of organsims in tissue secretions
what are severe cases of cryptococcosis tx with?
- amphotericin B
- flucytosine
what are less severe cases of cryptococcosis tx with?
fluconazole
cryptococcosis what is the usual px for cryptococcosis
usually poor bc pts are immunocompromised
also known as mucormycosis, it is several genera of molds, including Mucor, Rhizopus, and Absidia
zygomycosis
what population does zygomycosis affect?
severe diabetic or immunocompromised pts
what is zygomycosis in oral region
rhinocerebral
what is the clinical presentation of zygomycosis ?
- nasal obstruction, bloody nasal discharge
- facial pain, swelling, palatal perforation
- black necrotic lesions
- with progression superiorily, visual disturbances and blindness result
- seizures and death occur with intracranial invasion
what is the dx of zygomycosis based on?
- histopathologic findings bc culture is too low
- large branching nonseptate hyphae with extensive tissue necrosis
- hyphae often seen plugging small blood vessels
what type of px does zygomycosis have?
poor
very common deep fungal infection that is second in frequency to candidiasis
aspergillosis
spectrum of disease that includes allergy, localized infection, or invasive
aspergillosis
the clinical features of aspergillosis vary depending on what?
immune status and extent of tissue invasion
maxillary sinus fungus ball
aspergilloma
does aspergillosis cause tissue damage?
yes, it is locally invasive
what is the extent of aspergillosis in immunocompromised pts?
disseminated
a biopsy of aspergillosis shows what?
branching septate hyphae
- occlusion of small blood vessels by hyphae
- granulomatous inflammation if the host is NOT immune compromised
if a pt is immunocompromised with aspergillosis, is there inflammation?
only a little (granulomatous if the host is NOT immune compromised)
what is the tx of aspergillosis?
non-invasive = debridement invasive = voriconazole or itraconazole (with or without debridement)
what is the px of aspergillosis pt with normal immune status?
good
what is the px of aspergillosis pt with immunocompromised status?
poor
was approved for topical use in the US, but tastes bitter and is no longer available
amphotericin B
IV forms of this are used to tx life threatening diseases?
amphotericin B
first oral antifungal agent that could be absorbed systemically
ketoconazole
requires acidic stomach environment to work
ketoconizole
drug that has a convenient single daily dose and has problems with drug interactions and idiosycratic hepatotoxicity (1 in 12,000)
ketoconizole
drug that is approved for tx histoplasmosis
- well absorbed, daily dosing
- minimal side effects
- quite expensive
itraconazole (sporanox)
triazole compound; IV or oral
- approved for tx candida, aspergillus and several others
- side effects include PHOTOSENSITIVITY
- 1rst line therapy for INVASIVE ASPERGILLOSIS
- quite expensive
voriconazole
