Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Unit 4 > Micro - pulminary fungal infections > Flashcards

Micro - pulminary fungal infections Flashcards

1
Q

What is the route of infection for pulmonary fungal infections?

A

spore inhalation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What activates pulmonary fungi to cause infection?

A

body heat - thermal dimorphism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are arthroconidia?

A

Arthrospores; infectious form form Coccidioides that causes coccidioidomycosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Where do Coccidioides reside (source of infection)?

A

soil - carried by wind when soil is disturbed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Where are Coccidioides endemic to?

A

southwest US and Latin America

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the two most common fungi that cause coccidioidomycosis?

A

Coccidioides immitis and C. posadasii

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is the cause for the spike in cases this century?

A

endemic areas (southwest US and Latin America - Phoenix and Tucson AZ, Bakersfield and Fresno, CA, El Paso TX.) have become geriatric

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

T/F Spherules and endospores are not infectious

A

true

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is an associated clinical symptom of coccidioidomycosis?

A

erythema nodosum (skin inflammation that results in reddish, painful, tender lumps - most commonly located in the front of the legs)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Where in the pulmonary tract do Coccidioides undergo thermal dimorphism?

A

terminal bronchioles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is different about source of infection from infectious dimophic fungi vs TB?

A

infectious dimophic fungi are from american soil

TB is from foreign crops

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What form does Coccidioides adopt once it undergoes undergo thermal dimorphism?

A

spherule

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

T/F morality is low but morbitity is high from coccidioidomycosis

A

true

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

T/F coccidioidomycosis will trigger a positive PPD skin test?

A

true - 80% of residents in endmic population centers are PPD positive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is most important determinant of morbidity coccidioidomycosis?

A

Dose of pathogen exposure - single IU (reproductive spore) can trigger positive PPD but high dose causes more symptoms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What makes the pherule difficult to eradicate by the immune system?

A

Thick, doubly-refractive wall

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Can coccidioidomycosis be transmitted from patient to patient?

A

No - must have independent exposure to spores from soil

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Coccidioides spherules fill with endospores once they undergo thermal dimohphism in terminal bronchioles. Rupture of spherules causes endospores so spread around lungs but an additional step is needed to cause infection, what is it?

A

macrophage engulphment and cytokine release

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What immune response clears most Coccidioides when inhaled?

A

alveolar macrophages

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What immune response clears Coccidioides when there is large dose exposure and significant infection?

A

Cell mediated immunity - forms small nodule in lung similar to TB that contains and slowly eradicates infection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What are most common symptoms of coccidioidomycosis (moderate dose exposure)

A

non-specific flue like symptoms with low-moderate dose

In adults: Erythema nodosum is most common clinical symptom if infection persists to chronic phase

In children:Erythema multiforme

Low dose is usually cleared and asymptomatic but still causes +PPD

higher dose can cause pneumonia or dissemination

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What 2 factors are most likely to cause pneumonia or dissemination in coccidioidomycosis?

A

high dose exposure or if someone is immunosuppressed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What cell types are involved in acute phase of coccidioidomycosis? Chronic phase?

A

alveolar macrophages

lymphocytes and histiocytes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What are the roles of lymphocytes and histiocytes in the chronic phase of coccidioidomycosis?

A

initiate granuloma and giant cell formation (containment)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What other diseases resemple the clinical features of coccidioidomycosis

A

Valley fever or desert rheumatism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What are the clinical symptoms of severe symptomatic coccidioidomycosis (5)?

A 
Fever
Arthralgias
Erythema nodosum
Erythema multiforme
Chest pain
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

How is coccidioidomycosis disseminated in immunosupressed patients?

A

intracellular travel in macrophages and hematogenous spread

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What are risk factors for coccidioidomycosis?

A

advanced age, immunocompromise, late-stage pregnancy, occupational high-level exposure (farmers, construction workers, archaeologists), Black or Filipino race

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What tissues are primarily affected by disseminated coccidioidomycosis?

A

bones, meninges, skin or lymph nodes (presents as soft tissue abscess)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What can coccidioidomycosis trigger causing rapidly fatal progression?

A

immune anergy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Localized extrapulmonary infection by Coccidioides is usually caused by what?

A

contaminated injury

usually resolves without treatment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

contaminated Coccidioides infections can cause what symptoms?

A

influenzalike illness (fever, cough)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What lung changes can be seen on x-ray with coccidioidomycosis?

A

Infiltrates
Adenopathy
Effusions
Nodules resembling malignancy (biopsy)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

T/F PPD will be negative for disseminated coccidioidomycosis infection in immunosuppressed pt?

A

true

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

T/F PPD will be positive if there is a cleared or contained coccidioidomycosis infection

A

true

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

What is the incubation period for Coccidioides?

A

7-30 days

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

When are people most likely to become infected with Coccidioides?

A

summer or autumn

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

T/F erythema nodosum/multiforme is caused spherule migration to shins or other areas causing painful rashes

A

False - spherules stay in lungs unless severe disseminated infection - nodosum symptoms are caused by overactive immune response (type 4 hypersensitivity rxn)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

T/F coccidioidomycosis associated hypersensitivity rxn may manifest in eye as conjunctivitis

A

true

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

coccidioidomycosis disseminated to bone causes what?

A

osteomyelitis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

What differentiates coccidioidomycosis disseminated meningitis from bacterial meningitis?

A

symptoms similar, but onset is slow (weeks) with coccidioidomycosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

T/F Dramatic sweats, dyspnea, fever, weight loss are symptoms of disseminated coccidioidomycosis infection

A

true

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

How do you culture Coccidioides from biopsy?

A

Sabouraud’s agar at 25C

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

what is appearance of positive coccidioidomycosis infection in culture?

A

cottony white mold composed of hyphae with arthrospores: cultures are infectious!

Handle in Biosafety Level 3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

T/F serology titers are usefull for monitoring progression of coccidioidomycosis infection

A

true - IgG from blood and/or CSF spike indicates dissemination

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

True/false a PCR test for coccidioidomycosis is available

A

true

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

What CSF findings would you see from coccidioidomycosis disseminated meningitis?

A

lymphocytic pleocytosis, elevated protein, hypoglycorrhachia ( a low glucose level), eosinophilia, CF (compliment fixing) IgG

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

T/F serology for coccidioidomycosis are specific but less sensitive (i.e. prone to false negatives)

A

true

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

Treatment for persistant or disseminated infections

A

Amphotericin B and long-term itraconazole

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

coccidioidomycosis meningitis is initially treated with what?

A

fluconazole, continue as a long-term suppressive

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

severe or prolonged coccidioidomycosis meningitis is treated with what?

A

intrathecal amphotericin B

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

What does long term amphotericin B treatment cause? How would you treat this?

A

immunogenic symptoms

corticosteroids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

What is treatment for mild coccidioidomycosis (e.g. flue like symptoms or mild pneumonia)?

A

No treatment or oral azoles (no data demonstrate faster or better resolution with oral azoles)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

Who must be treated regardless of sevarity of coccidioidomycosis symptoms?

A

predisposed to complications: severe immunosuppression, diabetes, Black/Fillipino, cardiopulmonary disease, (oral azoles)

late term pregnancy (Amphotericin B) because azoles are contraindicated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

What is the most common systemic mycosis

A

histoplasmosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

Where are histoplasmosis infections most common in US?

A

Ohio, Missouri, and Mississippi River valleys: acidic damp soil with high organic content; ~80% of people who live there are exposed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

What are two (asexually reproducing) ENVIRONMENTAL forms of Histoplasma capsulatum?

A

Tuberculate macroconidia

Microconidia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

What are the features that distinguish Tuberculate macroconidia from Microconidia?

A

Tuberculate macroconidia - Thick walls, Fingerlike projections

Microconidia -Smaller, thin, smooth-walled

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

Which forms of Histoplasma capsulatum are infectious?

A

Microconidia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
60
Q

What is the source of Histoplasma capsulatum infection?

A

soil,

bird droppings, esp from starlings or bat guano

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
61
Q

T/F Histoplasma capsulatum must be inhaled to cause infection

A

true

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
62
Q

95% of Histoplasma capsulatum infections are cleared by alveolar macrophages, but ones that aren’t evade immune system by what mechanism?

A

survive endocytosis & lysosomal fusion by producing bicarbonate & ammonia; raises pH and inactivates hydrolytic enzymes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
63
Q

How does Histoplasma capsulatum incubate and spread?

A

evade macrophage lysosomal fusion by producing bicarbonate and ammonia to raise pH, then convert to yeast form and replicate

spread hemotogenous via macrophages

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
64
Q

What kills most Histoplasma capsulatum infections?

A

cell mediated immunity facilitates more efficient intracellular killing by macrophages

For those that escape macrophage endocytosis - cell mediated immune system forms granulomas, eventually calcify, contain infection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
65
Q

What are DEFINING symptoms of severe Histoplasma capsulatum infections

A

Pancytopenia

Ulcerated lesions on tongue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
66
Q

What symptoms can high dose Histoplasma capsulatum exposure cause?

A

High-dose exposure may cause pneumonia w/ cavitary lung lesions on primary infection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
67
Q

Which patients are most suseptible to severe Histoplasma capsulatum infection?

A

Very young, very old, immunosuppressed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
68
Q

T/F PPD is useful for Histoplasma capsulatum

A

False - many false positives

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
69
Q

Both Histoplasma capsulatum and Coccidioides are thermally dimorphic and transform to yeast in tissue, what differentiates them?

A

Formation of spherule

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
70
Q

What are similarities between histoplasmosis and TB?

A

Both for granulomas in the lungs
Both macrophages as Trojan Horses during dissemination
Both require months-years of drug treatment to clear
Both are airborne
Both cause weight loss

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
71
Q

What is a difference between TB and histoplasmosis?

A

drugs used for treatment differentiate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
72
Q

Treatment for histoplasmosis (lung vs disseminated vs meningitis)?

A

spreading in lung, oral itraconazole 6-12 weeks

disseminated, amphotericin B: must use liposomal if any kidney problems, follow w/ itraconazole for at least 1 year

meningitis, fluconazole (penetrates spinal fluid well)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
73
Q

what fungi causes blastomycosis

A

Blastomyces dermatitidis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
74
Q

T/F infectious cause of blastomycosis is mold form hyphae with small pear shape called conidia

A

True

Hyphae = long, branching filamentous structure of a fungus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
75
Q

Yeast form of blastomyces has what features?

A

round w/ doubly refractive wall

single broad-based bud

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
76
Q

What regions are blastomyes endemic to?

A

Eastern north america and great lakes region

grows in wet rich soil

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
77
Q

What is the virulance factor for blastomyces?

A

Yeast, not mold, produce immune-modulator BAD1 on cell surface

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
78
Q

What is the infection rate of blastomyces?

A

~50% Asymptomatic infection : successful clearance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
79
Q

How does immune system typically defeat blastomyces?

A

granulomatous response, may develop pulmonary symptoms in process

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
80
Q

When would pulmonary symptoms present with blastomyces infection?

A

(~45 days post exposure)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
81
Q

Who is susceptible for dissemination, hematogenous seeding of many possible sites

A

Immunosuppressed or preexisting pulmonary disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
82
Q

T/F Untreated symptomatic cases of blastomycosis have significant mortality rate (~40%)

A

true

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
83
Q

What are characteristic features of blastomycosis on exam?

A

Mild form: nonspecific flulike illness, resolves spontaneously

Pneumonia: high fever, chills, cough w/ mucopurulent sputum, pleuritic chest pain, occasionally EN

Chronic illness: looks like TB: pulmonary symptoms w/ weight loss, night sweats, hemoptysis

Fast, severe form: ARDS w/ fever

Any may also include skin lesions, bone/joint pain

Chest Xray is abnormal but variable
Bronchoscopy with needle biopsy may be useful

84
Q

T/F Skin lesions are more common with blastomyces than coccidioides or histoplasma

A

true

85
Q

T/F blastomyces can be cultured from skin lesion

A

true

86
Q

How do you diagnose blasomycosis?

A

Sputum microscopy is 75% diagnostic IF pt have pneumonia

Tissue biopsy is other method -

87
Q

What would you expect to find from microscopy of sputum or culture?

A

hyphae w/ small pear-shaped conidia

88
Q

T/F PPD and serology are specific for blastomycosis

A

False! NOT specific - prone to false positive

89
Q

Classic culture presentation of histoplasmosis

A

ovoid yeast form inside macrophages - larger than bacteria

90
Q

Expected blood findings from histoplasmosis in disseminated dissease?

A

pancytopenia

91
Q

How would you culture histoplasma capitum?

A

Sabouraud’s agar - 2 cultures necessary unlike coccidiomycoces

25C for tuberculate macroconidia
37C for yeast

92
Q

T/F ELISA for histoplasmosis can be performed from serum or urine

A

true for histoplasma polysaccharide antigen

93
Q

T/F serologic tests are useful for diagnosis of histoplasmosis

A

False - Not specific - antibody titers can be useful, but may cross-react w/ other fungal infections, or turn negative in immunosuppressed

94
Q

What is causes South American blastomycosis, Lutz-Splendore-Almedia disease?

A

Paracoccidioides brasiliensis

AKA Paracoccidioidomycosis

95
Q

T/F Paracoccidioides are dimorphic with yeast and mold form

A

true

96
Q

What defines mold form of Paracoccidioides?

A

thin, septate hyphae

97
Q

What defines yeast form of Paracoccidioides?

A

thick-walled w/ multiple buds

98
Q

Where is Paracoccidioides endemic to?

A

rural Latin America

99
Q

Diagnose by sputum microscopy for yeast, culture for hyphae w/ pear-shaped conidia, biopsy for yeast w/ supperating (not caseating) granulomas.

A

Blastomyces (North American blastomycoses)

100
Q

endemic to US Southwest, mold grows in wet weather, releases infectious arthrospores in dry, spores inhaled, change form.

A

Coccidioides (coccidioidomycosis)

101
Q

Treat if predisposed to complications (oral azoles), meningitis (fluconazole), pregnant or disseminated (Amphotericin B).

A

Coccidioides (coccidioidomycosis)

102
Q

Which fungus?

culture for hyphae w/ pear-shaped conidia

A

Blastomyces (North American blastomycoses)

103
Q

This pathogenesis describes what type of infection?

Spores are inhaled
Early lesions occur in lungs
Asymptomatic infection common
More severe infection includes oral mucous membrane lesions, lymph node enlargement
Dissemination is possible if immunosuppressed (CMI) or untreated for years
Total untreated mortality 16-25%

A

Paracoccidioides (Paracoccidioidomycosis/South American blastomycosis/Lutz-Splendore-Almedia disease)

104
Q

Which fungus?

60% Mild: asymptomatic or flulike clearance by innate or containment by CMI

A

Coccidioides (coccidioidomycosis)

105
Q

thermally dimorphic (mold/yeast), endemic to Ohio, Missouri, and Mississippi river valleys, soil-based, infectious microconidia can be kicked up by construction projects, causes pulmonary symptoms, previously-healthy usually clear or contain in granulomas, higher-dose infection produces TB mimic, CMI-deficient host disseminates in macrophages (yeast survive lysosomal fusion), look for pancytopenia and ulcerations on tongue. Also for diagnosis: history (birds, bats, endemic area, immunocompromised, occupation), biopsy for yeast in macrophages, cultures for dimorphism, ELISA for antigen. Treat serious lung w/ itraconazole, meningitis w/ fluconazole, disseminated w/ Amphotericin B.

A

Histoplasma capsulatum

histoplasmosis

106
Q 
Which fungus? 
Dimorphic fungus
Mold form has thin, septate hyphae
Yeast form is thick-walled w/ multiple buds
Endemic to rural Latin America
A

Paracoccidioides (Paracoccidioidomycosis/South American blastomycosis/Lutz-Splendore-Almedia disease)

107
Q

This pathogenesis describes what type of infection?

Infection by inhalation of conidia
Monocytes, macrophages, neutrophils readily kill conidia but once yeast conversion takes place begin to slow down.

slowed killing due to BAD1 immune modulator on yeast
~50% Asymptomatic infection : successful clearance
Most of remainder contain infection with granulomatous response, may develop pulmonary symptoms in process (~45 days post exposure)
Immunosuppression or preexisting pulmonary disease predispose to dissemination, hematogenous seeding of many possible sites

Untreated symptomatic cases have significantmortality (~~40%)

A

Blastomyces (North American blastomycoses)

108
Q

Which fungus?

KOH mount for yeast cells w/ multiple buds
Stain biopsies with silver for yeast cells, adult form also granulomas
Culture on Sabouraud takes 2-4 weeks
Serologic testing not available outside endemic area
Skin test not helpful
CSF smear is seldom helpful

A

Paracoccidioides (Paracoccidioidomycosis/South American blastomycosis/Lutz-Splendore-Almedia disease)

109
Q

Which fungus?

Acute febrile respiratory illness 3-14 days after exposure

A

Histoplasma capsulatum

histoplasmosis

110
Q

biopsy for spherules

A

Coccidioides (coccidioidomycosis)

111
Q

This pathogenesis describes what type of infection?

infectious microconidia can be kicked up by construction projects, causes pulmonary symptoms, previously-healthy usually clear or contain in granulomas, higher-dose infection produces TB mimic, CMI-deficient host disseminates in macrophages (yeast survive lysosomal fusion

A

Histoplasma capsulatum

histoplasmosis

112
Q

Which fungus?

History: residence in or travel to an endemic river valley, occupational exposure from soil, birds, bats, immune predisposition

A

Histoplasma capsulatum

histoplasmosis

113
Q

Which fungus?

Fever
Arthralgias
Erythema nodosum
Erythema multiforme
Chest pain
High morbidity, low mortality
A

Coccidioides (coccidioidomycosis)

114
Q

Which fungus?

Pancytopenia
Ulcerated lesions on tongue

A

Histoplasma capsulatum

histoplasmosis

115
Q

Which fungus?

Risk factors: age, race, pregnancy, immunocompromise, occupational high exposure

A

Coccidioides (coccidioidomycosis)

116
Q

Which fungus?

Endemic in southwest US and Latin America

A

Coccidioides (coccidioidomycosis)

117
Q 
Which fungus? 
thermally dimorphic (mold/multibud yeast)
A

Paracoccidioides (Paracoccidioidomycosis/South American blastomycosis/Lutz-Splendore-Almedia disease)

118
Q

Which fungus?

serology for dissemination

A

Coccidioides (coccidioidomycosis)

119
Q 
Which fungus? 
thermally dimorphic (mold/yeast),
A

Either Histoplasma or Blastomyces

120
Q

Which fungus?

Diagnose by sputum microscopy for yeast

A

Blastomyces (North American blastomycoses)

121
Q

Which fungus?

Diagnose by pus or tissue KOH mount for yeast with multiple buds

A

Paracoccidioides (Paracoccidioidomycosis/South American blastomycosis/Lutz-Splendore-Almedia disease)

122
Q

Which fungus?

treatment involves healthier lifestyle (semi-opportunistic).

A

Paracoccidioides (Paracoccidioidomycosis/South American blastomycosis/Lutz-Splendore-Almedia disease)

123
Q

Which fungus?

biopsy for yeast w/ supperating (not caseating) granulomas

A

Blastomyces (North American blastomycoses)

124
Q

Moderate acute: pneumonia w/ purulent sputum, Moderate chronic: mimics TB, Severe acute: ARDS. May include EN or ulcerating skin lesions.

A

Blastomyces (North American blastomycoses)

125
Q

endemic to rural Latin America, severe in children/immunocompromised, moderate in adults, usually men in agriculture or construction.

A

Paracoccidioides (Paracoccidioidomycosis/South American blastomycosis/Lutz-Splendore-Almedia disease)

126
Q

Adult form has very long latency, skin&mucous lesions. Diagnose by pus or tissue KOH mount for yeast with multiple buds, culture.

A

Paracoccidioides (Paracoccidioidomycosis/South American blastomycosis/Lutz-Splendore-Almedia disease)

127
Q

Innate immunity clears most cases, destroys conidia easily, yeasts are harder to kill (BAD1), graulomatous response contains most, immunosuppression predisposes to hematogenous spread

A

Blastomyces (North American blastomycoses)

128
Q

thermally dimorphic (mold/spherule), endemic to US Southwest, mold grows in wet weather, releases infectious arthrospores in dry, spores inhaled, change form. 60% Mild: asymptomatic or flulike clearance by innate or containment by CMI, moderate: valley fever/ desert rheumatism: pulmonary+EN, severe: major pneumonia or dissemination (either bare or in macrophages). Risk factors: age, race, pregnancy, immunocompromise, occupational high exposure. Diagnose by exam, history, PPD, biopsy for spherules, culture for dimorphism, serology for dissemination. Treat if predisposed to complications (oral azoles), meningitis (fluconazole), pregnant or disseminated (Amphotericin B).

A

Coccidioides (coccidioidomycosis)

129
Q

thermally dimorphic (mold/multibud yeast), endemic to rural Latin America, severe in children/immunocompromised, moderate in adults, usually men in agriculture or construction. Adult form has very long latency, skin&mucous lesions. Diagnose by pus or tissue KOH mount for yeast with multiple buds, culture. Treat w/ itraconazole, Amphotericin B if severe, combine with healthier lifestyle (semi-opportunistic).

A

Paracoccidioides (Paracoccidioidomycosis/South American blastomycosis/Lutz-Splendore-Almedia disease)

130
Q

thermally dimorphic (mold/yeast), endemic to Eastern US. Innate immunity clears most cases, destroys conidia easily, yeasts are harder to kill (BAD1), graulomatous response contains most, immunosuppression predisposes to hematogenous spread. Moderate acute: pneumonia w/ purulent sputum, Moderate chronic: mimics TB, Severe acute: ARDS. May include EN or ulcerating skin lesions. Diagnose by sputum microscopy for yeast, culture for hyphae w/ pear-shaped conidia, biopsy for yeast w/ supperating (not caseating) granulomas. Treat w/ itraconazole, fluconazole if meningitis, Amphotericin B if severe.

A

Blastomyces (North American blastomycoses)

131
Q

is widespread environmental, enabled by reduced CMI, suppresses host inflammatory response. Infection originates in lung but usually either clears or progresses to meningitis. Patient presents late in disease with meningitis and skin nodules or pulmonary symptoms. Diagnose by biopsy, CSF, crag. Treat with combinations of azoles and Amphotericin B.

A

Cryptococcosis

132
Q

hypersensitivity rxn to infection complicating asthma or CF, diagnose on exam, treat w/ itraconazole, sinus surgery, Xolair

A

Aspergillosis - ABPA (Allergic bronchopulmonary aspergillosis)

133
Q

Which infection is more likely to actually require treatment (greater virulance) vs require treatment once acquired?

blastomycoses
Paracoccidioidomycosis
coccidioidomycosis
histoplasmosis

A

blastomycoses

134
Q

fungus ball complicating cavitary lung disease, diagnose by air crescent on scan, treat w/ itraconazole and/or surgery

A

Aspergilloma (colonizing aspergillosis)

135
Q

Opportunistic fungal pathogens cause dangerous infection when paired with what risk factors?

A

prolonged neutropenia,
uncontrolled HIV or diabetes,
profound T-cell suppression

136
Q

Effective treatment of serious disease from opportunistic fungal pathogens must: (2 things)

A

addresses both the current infection and the underlying problem

137
Q

is a ubiquitous environmental mold, infection is rare overall but frequently fatal in predisposed population. May cause mycotoxicosis (contaminated grain), local infection (burns, prosthetic implants, contaminated contact lens solution), or deadly disseminated infection (prolonged neutropenia, HSCT recipients). Enters from sinus or wound site, circulates in blood, symptoms in skin, eye, lung. Diagnose by blood culture, histo, treat aggressively with surgery, amphotericin B, voriconazole, prognosis poor.

A

Fusarium

138
Q

very rare deadly invasive vasculitis by environmental mold, causes infarction, invades brain from sinuses. Predisposition by uncontrolled diabetes, iron overload, immunosuppression. Diagnose by biopsy for histo, treat with amphotericin B and aggressive surgical removal of diseased tissue, prognosis poor.

A

Mucormycosis caused by Mucor or Rhizopus

139
Q

mimics TB; try to diagnose by air crescent on scan, needle-aspirate lung fluid for microscopy

A

Aspergillosis CNPA (Chronic necrotizing pulmonary aspergillosis)

140
Q

respiratory distress with history of profound immunosuppression, diagnose by halo sign on scan, needle or tissue biopsy for histo

A

Invasive aspergillosis

141
Q

Treat with voriconazole+AmphotericinB, but prognosis is poor

A

CNPA and invasive Aspergillosis

142
Q

banana-shaped macroconidia

A

Fusarium

143
Q

Fusarium species that is the most common cause serious infection (50%)

A

Fusarium solani

144
Q

What are the 3 presentations of Fusarium pathogenesis?

A

Mycotoxicosis
Immunocompetent local infection
Immunosuppressed opportunistic infection

145
Q

virulence factors for Fusarium include:

A

immunosuppressive mycotoxins
collagenases
proteases
ability to adhere to prosthetic material

146
Q

What causes Immunosuppressed opportunistic fusarium infection?

A

Prolonged Neutropenia
Long-term use of steroids
Profound T-cell deficiency (as in pts receiving Hematopoietic stem cell transplantation)

147
Q

What causes mycotoxicosis?

A

trichothecene mycotoxins

148
Q

Where would you find immunocompetent local fusarium infection?

A

Skin (burns)
Cornea (contaminated contact lens solution)
Allergic sinusitis (like ABPA)
Colonization of prosthetics & catheters

149
Q

Primary species causing cryptoccocis

A

Cryptococcus neoformans and C. gattii

150
Q

5 seriotypes
A, D, AD = ?
B,C = ?

A

A, D, AD = Cryptococcus neoformans
B,C = Cryptococcus gattii

**grow at 37C

151
Q

What fungal species is environmental, found worldwide in soil contaminated w/ bird droppings, esp pigeon?

A

Cryptococcus neoformans

152
Q

What features describe criptococci (under microscopy)?

A

Oval yeasts w/ narrow-based buds

wide polysaccharide capsule

153
Q

What fungal species found in litter under eucalyptus trees?

A

Cryptococcus gattii

154
Q

Which Cryptococcus species causes less severe disease but prefers immunocompetent hosts (more common on West coast)?

A

Cryptococcus gattii

155
Q

T/F Cryptococci can be transmitted from human to human but only with direct blood transmission (e.g. organ transplants or needs sticks)

A

true - causes localized cutaneous disease

Otherwise non-human-human transmission

156
Q

What factors have increased incidence of cryptococcal meningitis?

A

Use of steroids, survival w/ malignancy, and AIDS

157
Q

T/F lung infection with cryptococci can be asymptomatic

A

true, or lead to pneumonia or dissemination

158
Q

Pathogenesis of cryptococci involves primary inhillation of spores into lungs. From there what typically happens in the immunocompetant host?

A

▪ Lung infection may be asymptomatic or lead to pneumonia
▪ Can can survive as simple yeast cell (capsule protects from phagocytosis), or if phagocytosed can cause intracellular infection in alveolar macrophages
▪ Can also be expelled from macrophage and dissemenate as simple yeast through blood or stay in macrophage as trojan horse
▪ Immunocompetent hosts restrict infection to lungs
▪ Successful host raises Helper Ts, skin test conversion, antibodies to capsule

159
Q

What is cause of tissue damage from c. neoformans?

A

very little inflammatory response or granuloma formation – organ damage is by tissue distortion from growing yeast

160
Q

What are virulance factors for criptococci?

A

capsule,
melanin in cell wall (antiphagocytic),
Phospholipase B for invading tissue

161
Q

What is a characteristic feature of C. neoformans dissemination?

A

meningitis w/ skin nodules

162
Q

T/F C. neoformans raises very little inflammatory response or granuloma formation

A

true!

163
Q

What is atypical about cryptococcal meningitis?

A

neck stiffness and fever are less common because can present and low level meningitis

most common symptoms: Headache, altered mental status, nausea and vomiting

Cryptococcomas - masses in CNS can cause focal neurologic damage

164
Q

What is “crag”? what is it used for?

A

serology test (short for cryptococcal antigen) involves latex agglutination for cryptococcal antigen in blood and CSF

165
Q

What is found on culture media (Sabouraud agar) with Cryptococcosis?

A

melanin

37C

166
Q

In Cryptococcosis, CSF stained with india ink will demonstrate what?

A

yeast w/ wide capsule (halo ring) – much larger than bacteria that cause meningitis

167
Q

T/F ruitine blood work may be normal in pt with Cryptococcosis

A

True - blunted immune response so no inflammation

168
Q

Altered mental status in HIV positive pt should be tested for what?

A

Cryptococcosis encephalitis/meningitis

169
Q

What is most useful test early on in Cryptococcosis?

A

crag from blood or CSF

170
Q

What is treatment for cryptococcal meningitis or cryptococcoma?

A

Amphotericin B (liposomal if kidney issues) plus flucytosine for 2 weeks followed by 10 more weeks of fluconazole

171
Q

T/F criptococcus can infect the prostate

A

true

172
Q

what is treatment for Prostate Cryptococcosis

A

Fluconazole

173
Q

Treatment for pulminary criptococcosis?

A

In immunocompetent patients may not need treatment; can use 6-12mo fluconazole or itraconazole

174
Q

Treatment criptococcosis of Skin, bones, other:

A

Amphotericin B

175
Q

What features define Aspergillus?

A

Septate (divided) hyphae w/ V-shaped branches

176
Q

What are the 4 diseases caused by Aspergillus

A

1) Allergic bronchopulmonary aspergillosis (ABPA)
2) Aspergilloma or Colonizing Aspergilliosis: “Fungus ball” in lung
3) Chronic necrotizing pulmonary aspergillosis (CNPA)
4) Invasive aspergillosis

177
Q

Source and pathogenesis of asperigillus?

A

Widespread on decaying vegetation worldwide
Infectious conidia are airborne
Conidia colonize abraded skin, burns, cornea, ear, sinuses, lung
Healthy macrophage and neutrophil response eradicates fungus, but some Aspergillus produce toxic metabolites that inhibit it, so do corticosteroids

178
Q

What diseases are associated with asperigilloma?

A

TB, cystic fibrosis (colonizes cavitary lesions forming mass)

179
Q

What cause can cause pneumonia w/ hemoptysis and granulomas in immunocompromised patients?

A

chronic necrotizing pulmonary aspergillosis

difficult to diagnose, high mortality

180
Q

What are the virulence factors for aspergillus?

A

Gliotoxin: immunosuppressive
Toxic metabolites interfere with phagocytosis and opsonization
Proteases may be involved in tissue invasion

181
Q

What is this seen in?

Xray or CT may show “grape cluster” or “hand in mitten” clusters of mucus-clogged bronchi

A

Allergic bronchopulmonary aspergillosis

182
Q

What are the features/symptoms of Allergic bronchopulmonary aspergillosis

A

▪ Positive skin test for Aspergillus allergy with asthma or CF
▪ Coughing up brownish bronchial plugs containing hyphae
▪ Fever, wheezing & pulmonary infiltrates unresponsive to antibiotics
▪ Hemoptysis
▪ Uncontrolled asthma
▪ Purulent sinus drainage

183
Q

Mass in lung with “air crescent sign” that does not invade tissue and moves around when sitting up/laying down. associated with hemoptysis, cough, fever

a) cryptococcoma
b) coccidiomycoma
c) blastomycoma
d) aspergilloma

A

d) Aspergilloma

B + C are made up

a = CNS mass of C. neoformans that causes focal neuro deficits

184
Q

Clinical features of chronic necrotizing pulmonary aspergillosis

A

Subacute pneumonia unresponsive to antibiotics
Fever, cough, night sweats, weight loss
History of ineffective empiric treatment for TB

185
Q

Underlying diseases that predispose chronic necrotizing pulmonary aspergillosis

A

Underlying disease of alcoholism, collagen-vascular disease, chronic granulomatous disease or COPD, long term corticosteroid therapy

186
Q

Predisposing factors for invasive asperigillosis

A

History of profound immunosuppression or COPD with long-term corticosteroid therapy

187
Q

Clinical features of invasive asperigillosis

A

Fever, cough, dyspnea, pleuritic chest pain, neutropenia, sometimes hemoptysis, worsening hypoxemia

188
Q

CT scan for invasive asperigillosis shows:

A

characteristic halo sign: ground-glass infiltrate surrounding a nodular density. Represents a hemorrhage; invasive aspergilliosis is most common cause

189
Q

Diagnosis and pathologic features of invasive Aspergillosis

A

Septate hyphae branching at acute angles invading tissue
• Acute inflammatory infiltrate
• Tissue necrosis
• Blood vessel invasion
• High serum levels of glactomannan antigen (ELISA)

190
Q

Diagnosis and pathologic features Allergic bronchopulmonary aspergillosis

A
  • High levels of aspergillus-specific IgE, eosinophilia

* Mucus with degenerating eosinophils and hyphae

191
Q

Mucormycosis is caused by what fungi?

A

Mucor, Rhizopus, Absidia, several others

Rhizopus - is big one and most common on STEP 1

192
Q

What is characteristic about prevalence and pathologic course of Mucormycosis

A

Very rare (~500/yr in US) life-threatening (50-85% mortality) sinus infections; invade brain

“death by sinus infection”

193
Q

What are risk factors for mucormycosis?

A

uncontrolled diabetes (MAJOR CORRELATION), neutropenia, burns, leukemia, IV steroids or TNF alpha blockers, iron overload

194
Q

What is route of transmission for mucormycosis?

A

airborne asexual spores - Usually inhaled, can also be ingested or introduced by trauma

195
Q

T/F mucromycosis is highly associated with AIDS

A

false

196
Q

What is the main host defense against mucormycosis infection?

A

neutrophils (innate immuninty - cell mediated may not play large role)

197
Q

Where do mucormycoses proliferate?

A

walls of blood vessels - Cause infarction and necrosis of tissue downstream from blocked vessel

very high mortality if dissociated (~100%)

198
Q

Common sites of infection for mucormycoses?

A

Paranasal sinuses, invading brain - leaves disfigurement if treated successfully (huge necrotic lesion) 50-70% mortality

199
Q

Blood findings in mucormycosis?

A

neutropenia, diabetic acidosis, iron overload

200
Q

T/F antigen testing and CSF findings are helpful for diagnosis

A

False! No useful antigen tests or CSF findings

201
Q

Biopsy of tissue infected with mucormycoses demonstrate:

A

NONSEPTATE HYPHAE w/ broad irregular walls and BRANCHES AT RIGHT ANGLES, vascular invasion and necrosis, neutrophil infiltration.

202
Q

What are 3 factors that complicate the diagnosis of mucormycosis?

A

It is rare
Diagnosic window is short
Initial symptoms may be nonspecific

203
Q

is a ubiquitous environmental mold, infection is rare overall but frequently fatal in predisposed population. May cause mycotoxicosis (contaminated grain), local infection (burns, prosthetic implants, contaminated contact lens solution), or deadly disseminated infection (prolonged neutropenia, HSCT recipients). Enters from sinus or wound site, circulates in blood, symptoms in skin, eye, lung. Diagnose by blood culture, histo, treat aggressively with surgery, amphotericin B, voriconazole, prognosis poor.

A

Fusarium

204
Q

is widespread environmental, enabled by reduced CMI, suppresses host inflammatory response. Infection originates in lung but usually either clears or progresses to meningitis. Patient presents late in disease with meningitis and skin nodules or pulmonary symptoms. Diagnose by biopsy, CSF, crag. Treat with combinations of azoles and Amphotericin B.

A

Cryptococcosis

205
Q

What differentiates aspergillus and fusarium in histology?

A

only possible if both yeast form and mold form of fusarium are present (both have acute branching hyphae)

Unit 4 (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions