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178 Cards in this Set
- Front
- Back
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What are the 3 stains used to visualize fungi under the microscope?
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mayer's mucicarmine
GMS PAS with diastase |
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What does Mayer's mucicarmine stain do?
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highlights the capsules of cryptococcus
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What does GMS stain do?
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silver stain that makes fungi show up black
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What does PAS with diastase do?
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most common fungi stain, they show up magenta
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What are the three genera of dermatophytes?
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trichophyton
microsporum epidermophyton |
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You can acquire dermatophytes from what 3 sources?
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Soil (geophilic)
Animals (zoophilic) Humans (Anthrophilic) |
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What demographic is most often affected by Tinea Capitis? Why?
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affects children. Doesn't affect adults because they have more sebum, which is fungicidal
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How can tinea capitis show up?
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scaly lesions, alopecia w/ black dots, kerion (abscess), inflammation
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What is the number one cause of tinea capitis? The number two cause?
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number 1: trichophyton tonsurans
number 3: microsporum canis |
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What demographic is most affected by tinea corporis?
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people in tropical regions and wrestlers
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How does tinea corporis manifest?
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ringworm, blisters, Majocchi's granuloma, Tinea Imbricata
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What is Majocchi's granuloma?
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an abscess in the hair follicle due to tinea corporis
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What is tinea imbricata?
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scaly patches covering a very large body area, seen in tina corporis in latin america, pacific, and southeast asia
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What species causes tinea corporis most commonly?
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trichophyta rubrum is most common
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How does tinea cruris manifest?
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scales and itching of the inner thigh in men. Does not affect scrotum. lichenified in chronic cases
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What species is responsible for the vast majority of tinea cruris infections?
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trichophyta rubrum
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What is the most common fungal infection in humans?
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tinea pedis, with 7.5 million cases in the US
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How does tinea pedis manifest?
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inflammation, pain, itching surrounding 4th toe
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What are some other complications of tinea pedis?
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diffuse hyperkeratotic (spreads to the whole sole), blisters, id reaction, 2 foot 1 hand syndrome
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What is the most common cause of tinea pedis in general? How about in young males?
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trichophyta rubrum in general, epidermophyton floccosum in young males
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What is onychomycosis?
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dermatophyte infection of toenails
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What is leukonychia mycotica?
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dermatophytes growing only on the surface of the toenail, not underneath it or anywhere else
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What is the most common presentation of onychomycosis?
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fungus invades from the distal and lateral edges of the nail, growing under and around it
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What is the most sensitive way to diagnose dermatophyte infection and identify the species?
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KOH examination
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What media are good for growing up dermatophyes?
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dermatophyte test media
sabouraud's media |
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What is the only dermatophyte detetable by a wood's lamp?
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tinea capitis, when it is fluorescent
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What are some topical ways to treat dermatophye infections?
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terbinafine is best. Can use other -afine or -conazole medicines
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What are some oral/systemic ways to treat dermatophyte infection?
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griseofulvin, -conazoles, terbutaline
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What do dermatophyes eat?
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keratin
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What does candida eat?
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sugar and plasma
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What can predispose you to candida infection?
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immunosuppressed state (antibiotics, steroids), diabetes, foreign objects, trauma
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True or false: candida is normal flora.
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True! That's why it's so common in immunosuppressed people
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What does a cutaneous candida infection look like?
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very red plaques, satellite lesions nearby, can cause pustules
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What is perleche?
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candida infection in the corners of the lips. Looks kind of like a cold sore
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What is thrush?
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candida infection of the mouth. Looks white, with satellite lesions
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Cutaneous candida manifest as intertrigo or paronychia; what do these mean?
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intertrigo= in skin folds
paronychia=base of the nails |
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How do you diagnose candida infection?
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clinical appearance, KOH if you are thorough, and culture/biopsy if you are totally anal
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How do you treat candida infections topically?
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gentian violet, nystatin, -conazoles, ciclopirox
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How do you treat candida infections systemically?
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oral fluconazole. Works best because it is very water soluble
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What bug is responsible for tinea versicolor?
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Malassezia furfur
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What does M. furfur eat?
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lipids
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How does tinea versicolor manifest?
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truncal distribution of yellow-brown-black scaly patches. Can also cause skin hypopigmentation
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How does tinea versicolor cause skin depigmentation?
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produces azaleic acid, which inhibits normal melanin formation
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What fungus is a likely cause of seborrheic dermatitis?
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m. furfur
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How do you diagnose tinea versicolor?
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clinical appearance, and "spaghetti and meatballs" appearance on KOH prep
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How do you treat tinea versicolor topically?
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selenium sulfide, -conazoles, ciclopirox
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How do you treat tinea vesicolor systemically?
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oral itraconazole. This is the best way to treat it.
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What fungal human pathogens are primarily in yeast form? (3 of them)
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dermatophyes, candida, m. furfur
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What human diseases are caused by fungus in the hyphae form? (6 of them)
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sporotrichosis
eumycotic mycetoma chromomycosis lobomycosis rhinosporidiosis |
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How does one get a localized fungal infection?
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these bugs live in the soil, and enter your skin through contaminated traumatic injury
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What fungus likes to live in peat moss, vegetation, and cat's claws?
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the one that causes sporotrichosis
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What does it mean to say that an infection is "sporotrichoid"?
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ulcers at the entry site, and swelling and ulcers at the draining lymph nodes
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What characterizes a fixed cuteneous sporotrichosis infection?
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verrucous ulcer at the site of injury, with no lymph node involvement (20% of cases)
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What populations are at higher risk for disseminated sporotrichosis?
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alcoholics, sarcoid, diabetes
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What is the best way to diagnose sporotrichosis?
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clinical presentation. Culture takes awhile, bugs aren't found on biopsy
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What is the most common treatment for sporotrichosis?
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oral itroconazole
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What are some supportive treatments that work somewhat against sporotrichosis?
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oral potassium iodide, local heat, surgical debridement
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What are the two subgroups of bugs that cause eumycota mycetoma?
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dark grain (dematiaceous)
light grain |
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What species cause dematiaceous eumycota mycetoma?
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madurella mycetomatis,
madurella grisea, phialophora jeanselmei |
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What characterizes the dematiaceous species that cause eumycota mycetoma?
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Dark grains in the pus, made of melanin
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What are the symptoms of eumycota mycetoma?
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subcutaneous abcess on foot, multiple fistulas leak pus onto the surface of the skin, pus contains light or dark specks
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What local cutaneous fungal infections can reach down and affect the bone?
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sporotrichosis, eumycota mycetoma
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How do you treat dematiaceous eumycota mycetoma?
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amphotericin B
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How do you treat non-dematiaceous eumycota mycetoma?
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oral itraconazole
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What is the last resort treatment for severe eumycota mycetoma?
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surgery
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How do you diagnose eumycota mycetoma?
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clinical presentation, KOH the exudate, X-ray to see if the bone is involved
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what sort of fungal infection will yield copper-colored sclerotic Medlar bodies on biopsy?
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Chromomycosis
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What are the symptoms of chromomycosis?
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pink papule that turns into ulcer or verrucous growth, with lymph blockage (elephantitis)
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How do you treat chromomycosis?
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surgery. Or, try oral terbutaline or itraconazole
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What characterizes lobomycosis?
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multiple hard nodules, affect only the dermis
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What is the treatment for lobomycosis?
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surgery
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What characterizes rhinosporidiosis?
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polyp-like lesions mostly in the nose that contain large fungal spores
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How do you treat rhinosporidiosis?
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surgery
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What characterizes protothecosis?
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fungal-like infection actually caused by an algae
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How do you catch protothecosis?
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water exposure, like if you clean aquariums a lot
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How do you diagnose protothecosis?
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biopsy: you will see morula-like endospores
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How do you treat protothecosis?
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surgery
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What is mycotoxicosis?
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when you ingest a toxic fungal product, either accidental or purposefully
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What was the example of mycotoxicosis that they mentioned in lecture? What were its effects?
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St Anthony's Fire. Caused alpha adrenergic block, vasoconstriction, tissue necrosis, death
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What three diseases can be caused by hypersensitivity to fungal spores?
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allergic rhinitis (hayfever)
bronchial asthma alveolitis |
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What are the five diseases caused by dimorphic fungi?
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sprotrichosis
blastomycosis coccidioidomycosis paracoccidioidomycosis histoplasmosis |
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What sort of soil does blastomycosis live in? Where in the US is it prevalent?
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needs humid, acidic soil. Found in the midwest and the south in the US.
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What fungus looks like a yeast with a thick, doubly-refracting wall, and buds with a single, broad base?
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blastomycosis
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How do you catch blastomycosis?
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breath it in
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What are some symptoms of blastomycosis infection?
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mild pneumonia, skin infections, bone infections, genitourinary symptoms
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What does blastomycosis look like when it infects the skin?
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papules that turn verrucous, with black dots on them from thrombosed vessels
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How do you diagnose blastomycosis?
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culture or skin biopsy is best
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What is the treatment for blastomycosis?
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itraconazole for normal infections, amphotericin for severe ones
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What kind of soil does coccidioidomycosis live in? What areas is it found in?
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dry, alkaline soil where it's hot. Found anywhere with cactus; the southwest, northern mexico, etc.
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What does a coccidioidomycosis yeast look like?
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a big ball with smaller ball-like spores inside it
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What fungus looks like barrels connected on a string in its hyphae form?
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coccidioidomycosis
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What are the 3 clinical diseases caused by coccidioidomycosis?
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pulmonary, systemic (rare), cutaneous.
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Which fungus can cause non-migratory arthralgia?
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coccidioidomycosis
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What is the best way to diagnose coccidioidomycosis?
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biopsy or KOH
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Where is paracoccidioidomycosis found?
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anywhere coffee grows
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What do paracoccidioidomycosis yeasts look like under the microscope?
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multiple narrow-based buds, making it look like a ship's wheel or mickey mouse
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What fungus causes mucosal ulcers first, skin ulcers next, and the ulcers have a rolled border?
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paracoccidioidomycosis
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How do you diagnose paracoccidioidomycosis infection?
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KOH or biopsy
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How do you treat paracoccidioidomycosis?
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itraconazole for mild cases,
amphoterecin for severe ones |
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How do you treat coccidioidomycosis?
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amphoterecin, and you can remove the skin/bone lesions surgically
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What kind of soil does histoplasmosis like to grow in?
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high nitrogen content. That's why it is associated with bird droppings or bat droppings
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What fungus has very thin, branching hyphae with big round spores at the ends?
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histoplasmosis
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What organs does histoplasmosis commonly affect?
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skin and adrenal glands
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Where are cryptococcus found? Also, where are the NOT found? Why?
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found in pigeon droppings. They don't survive in soil, because amebas like to eat them.
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What are the 5 common opportunistic fungal infections?
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cryptococcus
candida aspergillus mucormycosis pneumocystis |
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What do cryptococcus look like under the microscope
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really thick capsules, narrow-stalk budding
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How does disseminated cryptococcus infection usually present?
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meningitis
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What is the best way to diagnose cryptococcus?
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india ink stain the CSF
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What is the mortality rate for people with cryptococcus infections?
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15-30%, and that's with treatment.
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How can candida manifest as an opportunistic infection?
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endocarditis, UTI's, septicemia, skin, mucosa, eye
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Where is aspergillus found?
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everywhere! and they do mean everywhere!
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What does aspergillus look like on microscopy?
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budding bodies look like a goblet with lots of streaming spores coming out the top. Septate hyphae with acute angle branching
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What is the best way to diagnose aspergillus?
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biopsy
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What is the most common fungal disease to infect diabetics?
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mucormycosis
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What does mucormycosis look like on microscopy?
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hyphae have no cell walls between cells, branch at right angles
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Why does mucormycosis like to live in diabetic people?
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It likes heat, acidic pH, and likes to eat glucose and ketone bodies
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What are the clinical presentations of mucormycosis infection?
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rhinocerebral, pulmonary, abdominal, cutaneous
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What is the best way to diagnose mucormycosis?
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biopsy
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What is different about pneumocystis that sets it apart from all other fungi?
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has no ergosterol in the cell walls
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What drugs are used to treat pneumocystis?
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trimethoprim/sulfamethoxazole is best, dapsone and clindamycin sometimes work too. antifungals don't work.
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What characterizes pneumocystis pneumonia?
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dyspnea, fever, non-productive cough, tachypnea, tachycardia, cyanosis.
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How do you diagnose pneumocystis infection?
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patient history, X-ray, sputum culture
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How does amphoterecin B work?
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binds to ergosterol in fungal cell membrane, forms a pore that leaks ions out, and that kills the cell
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What are some adverse effects of amphoterecin B?
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very toxic! nephrotoxic, causes amenia, injection site reactions
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What are the pharmacokinetics of amphoterecin b?
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Must be given IV.
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How does Nystatin work?
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binds to ergosterol in fungal membranes, forms a pore which leaks out ions, and kills the cell
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What are the uses of nystatin?
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topical only, because it is too toxic for anything else
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what is the mechanism of action of the -conazole drugs?
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inhibits ergosterol synthesis by blocking 14-alpha-demethylase
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What is the most important side-effect of the -conazole drugs?
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inhibits P-450 metabolism of steroids, so you can get gynecomastia, etc.
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How does fluconazole differ from the other -conazoles in its pharmacokinetics?
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fluconasole can enter the CSF
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caspofungin works by what mechanism?
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inhibtis beta-glucan synthesis in fungal cell walls
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How must caspofungin be administered to patients?
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IV, it is not orally absorbed
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What is the mechanism of action of flucytosine?
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fluorouracil analogue, inhibits DNA synthesis
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What is the most important side-effect of flucytosine?
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bone-marrow depression
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What is the mechanism of actin of griseofulvin?
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binds to microtubules, halting cell mitosis in fungus
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Where in the body does griseofulvin deposit?
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binds to keratin, so it goes where ever keratin goes
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What is the mechanism of action of terbinafine?
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inhibits squalene metabolism, so the fungus can't make ergosterol
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Which hepatitises are transmitted by the oral/fecal route?
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Hep A and Hep E
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Which hepatitises are transmitted parenterally/sexually?
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Hep B, C, and D
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What are the symptoms of hepatitis?
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elevated AST/ALT, jaundice, and flu-like symptoms
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How long is the incubation period for Hep A?
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15-50 days
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How many serotypes are there of Hep A?
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only one. That's why the vaccine works so well.
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If a person has the following in their blood, what does it mean?
HepA antigen anti-HepA IgM anti-HepA IgG |
HepA antigen = you are infected, and can infest others
antiHepA IgM = currently infected within the past 6 months antiHepA IgG = vaccinated or past infection; immune to HepA |
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How does passive immunization work against HepA?
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because the incubation time is so long, giving IgG after a known exposure can prevent disease. Can co-administer with vaccine.
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Hep E is similar to Hep A. What are important differences?
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HepE has 10x more fatalities
Causes fulminant hepatitis in pregnant women No vaccine Uncommon in the US |
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If you have HepB s Antigens in your blood, what does that mean?
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diagnostic marker of acute and chronic Hep B
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If you have anti-HepB c IgM in your blood, what does that mean?
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You have an acute infection of Hep B
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What does it mean if you have HepB e Antigen in your blood?
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You have chronic hepatitis. Also, the more you have, the more contagious you are
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What are the genetics of HepB virus?
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DNA virus, but it replicates through RNA and reverse transcriptase
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What percentage of people in Africa and East Asia are infected with Hep B?
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over 50%
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How do you treat HepB?
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acute: do nothing
neonate: vaccinate chronic: interferon, lamivudine, HepB antibodies |
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What is the leading cause of liver disease worldwide?
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HepC
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What is the most common reason for a liver transplant?
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HepC infection
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Explain the genetics of HepC virus
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single stranded RNA, one long open reading frame
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What does it mean if you have antibody to HepC in your blood?
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You have an ongoing or past infection. Antibody is not protective
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What percent of people totally clear the virus from their system after having acute HepC?
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10-15%
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What are the symptoms of acute HepC?
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60-70% asymptomatic
20-30% have malaise, abdominal pain |
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What is the key to clearing a Hep C infection?
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active T-cell response
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What's the deal with Chronic HepC?
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very slow course, asymptomatic early on, can lead to liver cancer(1-2%), fatty liver(50-60%), cirrhosis(20-30%)
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What's the treatment for HepC?
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ribavarin, interferon. There is no vaccine
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Rickettsia: intracellular or extracellular? How do we visualize them on slides?
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obligate intracelllular. Stain with Giemsa to see them.
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What is the mechanism of Rickettsia infections?
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transmitted by arthropod bites, invade human endothelial cells, causing bacteremia
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What causes Typhus? What is its distinguishing feature?
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rickettsiae prowazekii. Rash on the trunk that moves to the extremities
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What causes Rocky Mountain Spotted Fever? What is its distinguishing feature?
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Rickettsiae Rickettsii. Rash on the hands and feet that moves to the trunk
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What causes Scrub Typhus? What is its distinguishing feature?
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Orientia tsutsugamushi. No rash, but an eschar at the site of the chigger bite
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Treatment of all rickettsial diseases is?
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Doxycycline
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Ehrlichia and Anaplasma bacteria live inside of what cells in your body?
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phagocytic cells
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What bug transmits Ehrlichia bacteria?
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hard ticks
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What bug transmits Anaplasma bacteria?
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Ixodes tick
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What disease does Coxiella Burnetti cause? Symptoms?
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Q fever. Flu-like symptoms, can lead to specific organ infection and malfunction
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How is Q fever transmitted?
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inhaled dust from ruminant herds
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What is the mechanism of infection of the Bartonella bacilliformis?
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invades endothelial cells, causing swelling.
invades RBCs, causing membrane deformation and lysis |
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What is the course of the disease caused by Bartonella bacilliformis?
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Oroya Fever (anemia) followed by Verruga Peruana (angio-proliferative nodules) at the site of the bite
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What bacteria causes Trench Fever?
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Bartonella quintana
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What bug causes Cat-Scratch Fever?
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Bartonella Henselae
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Symptoms of Bartonella Henselae?
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fever, swollen lymph nodes, papule at the site of contact
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What disease does Bartonella Henselae cause in immune-compromised patients? Symptoms, please?
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bacillary angiomatosis-peliosis. Big nodules appearing on skin. Cysts in liver and spleen filled with blood
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What is the treatment for bacillary angiomatosis-peliosis?
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macrolides
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