Fungal Infections Flashcards
which form of Candida Albicans is pathogenic? which form is commensal?
yeast form – commensal
hyphal form – pathogen
what is developed as C. Albicans converts from its yeast to hyphae form?
germinative or “germ” tubes
what 3 factors influence the development/progression of Candidiasis?
The host immune status
The oral mucosal environment
The virulence of the candidal strain
what are the 4 parts of the “spectrum of candidiasis infection”?
“Carrier” state
Superficial oral mucosal/cutaneous infection
Localized invasive candidiasis
Disseminated candidiasis
what 2 forms of Candidiasis are relatively rare/uncommon?
Localized invasive candidiasis
Disseminated candidiasis
what are the 3 types of ORAL candidiasis?
1) Pseudomembranous candidiasis
2) Erythematous candidiasis
3) Hyperplastic candidiasis
most oral candidiasis infections are of what type?
Erythematous candidiasis
what are some different examples of Erythematous candidiasis?
Acute atrophic candidiasis (“antibiotic sore mouth”) Central papillary atrophy Denture stomatitis? Angular cheilitis Perioral candidiasis Chronic multifocal candidiasis
_____________ Candidiasis is also known as “thrush”
Pseudomembranous
what are the characteristics of Pseudomembranous Candidiasis?
White, curdled milk or cottage cheese-like plaques
** plaques can be wiped-off
May be asymptomatic, but burning or unpleasant taste occasionally noted
what are the common sites of Pseudomembranous Candidiasis?
buccal mucosa, palate or tongue
what are the common sites of Erythematous Candidiasis infections?
tongue is common site; may involve palate, oral commissures, perioral skin
what form of candidiasis is defined as: “diffuse atrophy of dorsal tongue papillae, particularly after broad-spectrum antibiotics”
Acute atrophic candidiasis
Acute atrophic candidiasis is typically associated with a ________ sensation
burning
most cases of Central Papillary Atrophy are caused by what?
chronic candidiasis
Characteristics of central papillary atrophy:
Well-defined area of redness, mid-posterior dorsal tongue
Usually asymptomatic
____________ stomatitis is often referred to as “chronic atrophic candidiasis”
Denture stomatitis
T/F: the link between candidiasis and Denture stomatitis is well researched and consistent
False
Not much evidence to support this concept
what conditions are usually related to candidiasis, but may have other cutaneous bacterial microflora admixed
Angular Cheilitis
Perioral candidiasis
what are the characteristics of Angular chelitis?
Redness, cracking of corners of mouth
Often waxes and wanes
Typically responds well to topical antifungal therapy
what condition is often associated with lip-licking or chronic use of petrolatum-based materials?
Perioral Candidiasis
characteristics of Perioral candidiasis:
Redness, cracking of cutaneous surfaces around mouth
Typically responds well to topical antifungal therapy
what 3 conditions will be seen in someone with Chronic Multifocal Candidiasis?
Patient will have:
1) angular cheilitis
2) central papillary atrophy
3) a “kissing lesion” of the posterior hard palate
_____________ is also known as “candidal leukoplakia”
Hyperplastic Candidiasis
clinical features of Hyperplastic Candidiasis
White patch that CANNOT be rubbed off
Uncommon; generally anterior buccal mucosa
why can hyperplastic candidiasis be an especially problematic form of candidiasis?
because a true leukoplakia may have candidiasis superimposed on it
what condition is associated with specific immunologic defects related to how the body interacts with Candida albicans?
Chronic Mucocutaneous Candidiasis
under what conditions is Invasive Candidiasis usually seen
in situations of severe uncontrolled diabetes mellitus or immune suppression
how can a candidiasis infection be diagnosed?
A) Sometimes clinical signs and symptoms are sufficient
B) Exfoliative cytology
C) Biopsy - usually not necessary
what cellular host response can be seen during candidiasis?
Variable host response
- Microabscesses may be seen in the superficial epithelium
- Chronic inflammation of the C.T.
Acanthosis is often present during what types of infections?
candidiasis infections
In almost all cases of candidiasis, the candidal hyphae never penetrate deeper than the _________ layer
keratin
how can candidiasis infections be treated?
A) superficial infeciton- milder topical or systemic antifungal agents
B) Life-threatening infections usually require intravenous amphotericin B
list the features and disadvantages of Nystatin (Mycostatin)
A) Not absorbed systemically
B) Disadvantages: taste (bitter to many), multiple dosing schedule, patient compliance
what type of Nystatin prescription is usually given as a “cleaning soak” for dentures?
Nystatin Oral Suspension (100,000 ug/ml)
- soak denture overnight for 10 days in enough liquid to cover
___________ is a type of Imidazole antifungal agent
Clotrimazole (Mycelex)
what are the advantages/disadvantages of Clotrimazole (Mycelex)?
- No significant systemic absorption or side effects
- given as pleasant-tasting lozenges (troches)
- Disadvantage = dosing schedule (should be dissolved in mouth 5 times per day)
Fluconazole (Diflucan) is what type of antifungal agent?
Triazole antifungal agent
what are the advantages/disadvantages of Fluconazole (Diflucan)?
- Readily absorbed SYSTEMICALLY (drug interaction a worry)
- Daily dosing is convenient
- relatively expensive
what conditions are treated with topical antifungal creams?
angular cheilitis or perioral candidiasis
what are the 2 kinds of antifungal creams?
A) Mycolog II Cream- combination of nystatin and triamcinolone
B) Vytone Cream - combination of iodoquinol and hydrocortisone
Histoplasma capsulatum is a fungi endemic to what regions?
how is it spread?
Ohio and Mississippi River valleys
spores spread thru bird or bat droppings
what are the clinical features of ACUTE Histoplasmosis? Chronic? Disseminated?
Acute – may have flu-like illness
Chronic – cavitary pulmonary lesions
Disseminated – elderly, debilitated, or immunocompromised
oral lesions are usually seen in what form of histoplasmosis?
disseminated form
histoplasmosis oral lesions are usually seen in what areas of the mouth? what are their symptoms?
Affects tongue, palate, or buccal mucosa
Presents as a chronic variably painful ulcer or granular erythematous plaque
Clinically may be identical to malignancy
what histological features are characteristic of Histoplasmosis lesions?
Granulomatous inflammation, with or without necrosis
1-2 micron yeasts, usually within macrophages
Best visualized by silver stain (GMS) or PAS
how is histoplasmosis diagnosed?
Identification of characteristic small yeasts in tissue sections
Culture of the H. capsulatum organism from a suspected lesion
Serologic testing for antibodies or yeast-related antigens
what kinds of histoplasmosis infections require treatment? which do not?
Acute – no treatment is usually necessary
Chronic or disseminated histoplasmosis – may require amphotericin B
what 2 antifungals are used for mild cases of histoplasmosis?
Ketoconazole or itraconazole
which form of histoplasmosis has a mortality rate of 90% if left untreated?
Disseminated form
mortality drops to 7-23% if treated
Coccidioidomycosis is caused by what organism? where is it endemic to?
Coccidioides immitis
- Endemic to desert Southwest U.S.
Coccidioidomycosis, AKA “Valley fever”, represents what type of host reaction?
hypersensitivity reaction
T/F: more people are infected with Coccidioidomycosis than with Histoplasmosis each year
FALSE
Histoplasmosis infections are 5X as high as C. immitis
Clinical Features of Coccidioidomycosis infections:
Inhalation of spores
Flu-like illness in 40% of infected patients
Dissemination in less than 1% of those infected
what are the histological findings of Coccidioidomycosis?
- large (20-60 micron) spherules that contain endospores
- Variable host response, ranging from acute to granulomatous inflammation
- Diagnosis can be made by culture or biopsy
what drugs are used to treat Coccidioidomycosis?
Amphotericin B for disseminated cases
Fluconazole or itraconazole for milder cases
Cryptococcosis is caused by what organism? how is this organism spread?
Cryptococcus neoformans
- Organism lives in pigeon droppings
- Transmitted by air-borne spores
unlike other fungal infections, Cryptococcosis almost exclusively infects what group of people?
immunocompromised
Clinical signs/symptoms of Cryptococcosis:
Flu-like symptoms with initial pulmonary infection
Disseminates to meninges, resulting in headache, vomiting, neck stiffness
Cutaneous lesions may develop in 10-20%
T/F: Cryptococcosis rarely presents with oral lesions
true
Histopathology of Cryptococcosis:
A) 4-6 micron yeasts with a clear halo
B) Organisms may be visualized with mucicarmine, PAS, or silver stain (GMS)
what do the “clear halos” of cryptococcosis infections represent?
a mucopolysaccharide capsule
how are cryptococcosis infections treated?
- Severe cases- amphotericin B and flucytosine
- Fluconazole for less severe cases and for maintenance
- POOR PROGNOSIS because most patients are immunocompromised
_____________ is Also known as Mucormycosis
Zygomycosis
what genera of molds cause zygomycosis?
Mucor, Rhizopus, and Absidia
what population groups does Zygomycosis effect? what form does it take in oral regions?
Affects severe diabetic or immunocompromised patient
Rhinocerebral form in oral region
list the clinical features of Zygomycosis
Nasal obstruction, bloody nasal discharge
Facial pain, swelling, palatal perforation
Black, necrotic lesions
Seizures and death occur with intracranial invasion
as a Zygomycosis infection progresses superiorly, what can result?
visual disturbances and blindness result
how can Zygomycosis be diagnosed?
- based on histopathologic findings because culture is too slow
- Large, branching, nonseptate hyphae with extensive tissue necrosis
- Hyphae are often seen plugging small blood vessels
Treatments for Zygomycosis include what?
Radical surgical debridement
IV amphotericin B
If patient is diabetic, control of diabetes is important
Poor prognosis
After candidiasis, what is the next most common fungal infection?
Aspergillosis
what diseases can Aspergillosis cause? how is this organism transmitted?
- Spectrum of disease that includes allergy, localized infection or invasive aspergillosis
- Spores in soil, water, decaying organic debris
T/F: Aspergillosis is a concern in hospital setting
TRUE
it is a “nosocomial” infection
Clinical features of Aspergillosis infections:
- features depend on immune status and extent of tissue invasion
- Allergy- Allergic fungal sinusitis
- “Aspergilloma” – maxillary sinus fungus ball
- Tissue damage post-extraction or RCT
how is Aspergillosis diagnosed?
Biopsy shows branching septate hyphae
Occlusion of small blood vessels by hyphae
Granulomatous inflammation if the host is not immune compromised
Little inflammation if immunocompromised
Treatment options for Aspergillosis include what?
Non-invasive disease:
- debridement
Invasive disease:
- Voriconazole or itraconazole, with or without debridement
what are the advantages/disadvantages of Amphotericin B (Fungizone)?
- NOT for topical use anymore
- IV form is used to treat life-threatening systemic candidal (and other fungal) infections
- Nephrotoxicity is significant with standard amphotericin, but newer (expensive) liposomal preparations are relatively non-toxic
what are the advantages/disadvantages of Ketoconazole (Nizoral)?
- oral antifungal that can be absorbed systemically
- Requires acidic stomach environment
- Single daily dose is convenient
- LIVER TOXICITY
Problems with drug interactions and idiosyncratic hepatotoxicity (1 in 12,000)
what are the advantages/disadvantages of Itraconazole (Sporanox)?
Approved for treating histoplasmosis
Well-absorbed; daily dosing
Minimal side effects
Quite expensive
what are the advantages/disadvantages of Voriconazole?
Triazole compound; IV or oral
Approved for treating Candida, Aspergillus and several other species
Side effects include photosensitivity
1st line therapy - invasive aspergillosis
Quite expensive ($460)
what areas of the head/neck are Coccidioidomycosis lesions usually found?
Skin of central face may be affected
oral lesions are rarely described
