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SAM Exam 1 > Lecture 4-5 - Fungal dz (Walton) > Flashcards

Lecture 4-5 - Fungal dz (Walton) Flashcards

1
Q

Dimorphic fungi; saprophytic mycelial from in the soil produces infection spores, at body temperature these fungi transform into __ form

A

yeast

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2
Q

EXAM: types of dimorphic fungi

A 
blastomyces dermatitidis 
histoplasma capsulatum
coccidiodes immitis 
sporothrix schenckii 
cryptococcus neoformans
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3
Q

pathologic form of blastomycosis

A

extra-cellular yeast

thick, refractile, double wall, broad-based budding

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4
Q

endemic to mississippi, missouri, and ohio river valleys and great lakes

A

blastomycosis

more prominent after heavy rainfall (spore release) in warm weather
found near water in acidic sandy soils

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5
Q

increased __ and __ precede highest incidents of infection for blastomycosis

A

rainfall, temperature

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6
Q

why don’t all animals contract blastomycosis?

A

resident soil microbes typically destroy blastomyces in soil

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7
Q

poster child for blastomycosis

A

labs

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8
Q

how is blastomycosis transmitted

A

inhalation of spores
contaminated wound

  • not considered contagious
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9
Q

predispositions to blastomyces infection

A 
dogs 
males > females 
sporting dogs (labs, coonhounds), dobies 
large breeds 
2-4 yo
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10
Q

infection involves inhalation of __ which transforms into a yeast in the __

A

conidia
lungs (asexual budding)

can be spread systemically (blood or lymph)

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11
Q

inflammatory response often seen with fungal infections

A

granulomatous to pyogranulomatous

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12
Q

how does blastomycosis avoid the host’s IS (virulence)

A

BAD1 (impairs complement, can’t phagocytize the yeast)

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13
Q

any systemic dz or fungal dz always do a __ examination

A

fundic!

anterior uveitis, endophtalmitis, optic neuritis

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14
Q

most common CS of blastomycosis

A 
fever
lyphadenopathy
harsh lung sounds 
skin lesions 
cough, dyspnea, exercise intolerance
anorexia, wt. loos

usually localized to lungs and LNs but severe dz can be disseminated systemically

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15
Q

definitive dx for blastomycosis is based on __

A

cytologic, histopath, or culture

don’t culture! NEVER; can infect lab staff.

easiest and safest way is cytology

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16
Q

ELISA (ag serum assay) is a sensative test for blasto using serum or urine, but it can cross react with __ making positive result not dx for blastomycosis

A

histoplasma

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17
Q

__ are abnormal in over 85% of cases with blastomycosis and histoplasma

A

CXR; diffuse miliary pattern of lungs

both can have lytic boney lesions with periosteal reaction

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18
Q

broad-based budding on cytology

A

blastomycosis

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19
Q

does itraconazole penetrate CNS

A

No!

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20
Q

tx for blasto

A

itraconazole

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21
Q

blastomycosis tx; tx for at least __ and continue for at least __ past resolution of CS/rads

A

2-3mo

1-2mo

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22
Q

the most common systemic fungal dz in cat

A

cryptococcus neoformans

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23
Q

extra-cellular, thin walled, narrow based budding yeast with thick capsule

A

cryptococcosis

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24
Q

crytpococcus has a world wide distribution but there are very high incidences of it in

A

the western US (CA) and E. australia

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25
Q

found in bird excrement, rare in birds due to high BT, inhaled transmission, not contagious, common in cats and purebred dogs

A

cryptococcus

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26
Q

how does cryptococcus evade the host’s IS

A

Polysaccaride capsule (prevents phagocytosis)

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27
Q

associated with FeLV/FIV in cats and chronic steroids in dogs

A

cryptococcus

annimal on IS therapy more likely to get than FIV/FeLV animal

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28
Q

CS of cryptococcus in cat

A

sneezing, nasal d/c
SC masses
ocular lesions

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29
Q

CS of cryptococcus in dog

A

CNS signs (dull, blindness, hypermetria, CN defs), ocular lesions (chorioretinitis, retinal detach)

skin lesions less common in dogs

30
Q

best dx test for cryptococcus

A

skull rads/CT/MRI ; increased soft tissue in nasal cavity, lysis, deformity, contrast enhancing mass

31
Q

EXAM: definitive dx for cryptococcus

A

latex agglutination for Ag in serum, aqueous humor, or CSF

highly sensitive and specific, can quantify

cytology

32
Q

tx of cryptococcus

A

fluconazole preferred in cats (will penetrate CNS)

itraconazole is good first choice for cases w/o CNS involvement

very sick patient fluconazole + amphotericin B

can monitor titers to assess tx

33
Q

small INTRAcellular dimorphic fungus that has a halo and signet ring appearance with double ring, thick wall, and broad based budding

A

histoplasma capsulatum

34
Q

subtrop/tropic climate, mississippi, missoouri, ohio river valley, CA, TX

A

histoplasma capsulatum

similar distribution to blastomycosis

35
Q

primary reservoir organism for histoplasma

A

bat and decaying bird guano

not found in fresh feces of birds!

36
Q

more susceptible to histoplasma

A

cats, esp persians and cats coinfected with FeLV

37
Q

histoplasma microconidias are inhaled and transform into yeast which binds to __

A

CD11-18 integrins on alveolar macs and are phagocytized
replicate in macs, macs are destroyed, causes inflammation in lung

can be spred systemically

38
Q

subclinical infectious are common and most animals IS will effectively clear this infection

A

histoplasma

39
Q

most common CS in dogs with histoplasma

A

large bowel diarrhea

40
Q

most common CS in cats with histoplasma

A

profound wt. loss, fever, respiratory signs, GI dz (can dx off a rectal scrape)

41
Q

best way to dx histoplasma

A

cytology! (can be confused with sporothrix ) - lung wash or rectal scrape best

ag assay/ELISA (urine has higher sensitivity than serum). can cross react with blasto.

AGAIN, NO CULTURE; Don’t kill people

42
Q

2 fungi that have common overlap in radiographic findings and geographic regions

A

blasto and histo

43
Q

first choice tx for histoplasma

A

itraconazole

44
Q

barrel shaped arthrospores in chains found in the soil, spherules with endospores in tissues

A

coccidiodes immitis

45
Q

dry, warm climates, sandy soil, california, NM, arizona areas

A

coccidiodes immitis

46
Q

on histopath of coccidiodes immitis what will you see

A

spherules surrounded by neuts/WBC

47
Q

respiratory CS occur withing 3wk exposure and disseminated dz develops within __ exposure for coccidiodes

A

4mo

48
Q

dog w fever, painful swollen bone lesions, and travel hx to Arizona

A

coccidiodes

49
Q

most sensitive test for coccidiodes

A

ab serology (can’t tell if active infection though, but if see on cytology then know it’s an active infection)

ag titer has very low sensitivity; not recommended

50
Q

radiographic findings for coccidiodes

A

hilar lymphadenopathy on CXR

very proliferative bone lesions

51
Q

tx for coccidiodes

A

amputation for severe osteomyelitis, enucleation, itraconazole

52
Q

nasal aspergillosis causative agent? disseminated?

A

aspergillus fumigatus
aspergillus terreus

these are ubiquitous, opportunistic, saprophytic fungi

53
Q

GSD are susceptible to aspergillosis bc of __ deficiency

A

IgA mucosal def

54
Q

ag test for aspergillosis

A

aspergillus galactomannan ag (serum or urine)

can have false positive w other mycotic infections (blasto, histo) or plasmalyte IVF

55
Q

radiographic and AUS findings for aspergillus

A

diskospondylitis
osteomyelitis
thoracic lymphadenomegaly
pelvic dilation in kidneys (AUS)

56
Q

definitive dx for aspergillosis

A

culture and/or PCR

57
Q

another fungus with similar CS to cryptococcus that occurs in cat nose

A

sporothrix schenckii

58
Q

fungus that looks similar to histoplasmosis on cytology

A

sporothrix

59
Q

potentially zoonotic fungus

A

sporothrix!

60
Q

water molds that causes granulomatous and eosinophilic inflammation

A

pythium insidiosum and lagenidiosis sp.

61
Q

large, infrequently septate hyphae with non parallel wall

A

pythium, lagenidiosis

62
Q

how are oomycetes (water molds) different from fungi

A

cell wall lacks chitin and ergosterol (this is the target for most antifungal drugs!)
diploid
non-septate hyphae

63
Q

eosinophilic pyogranulomatous inflammation

A

water molds! pythium and lagenidiosis

64
Q

when ID a water mold it is important to do __ to determine prognosis and tx

A

PCR

65
Q

Tx for water molds

A

aggressive sx excision

antifungals

66
Q

insect killer fungi that are best dx on culture and tx with aggressive sx excision

A

basidiobolus and connidiobolus

67
Q

patients on __ are predisposed to infections with these opportunistic fungi (phaeohyphomycosis, hyalohyphomycosis)

A

cyclosporine

68
Q

__ is caused by pigmented fungi and __ is caused by nonpigmented fungi

A

phaeohyphomycosis (confined to skin and SC)

hyalohyphomycosis (local and systemic dz)

69
Q

dark-walled, irregularly septate hyphae or yeast-like cells containing melanin

A

phaeohyphomycosis

70
Q

non-pigmented, frequenly septate, branching hyphae that can cause disseminated dz

A

hyalohyphomycosis

SAM Exam 1 (15 decks)

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