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Block 9 Week 3 > Kozel > Lower Respiratory Tract Infections > Flashcards

Kozel > Lower Respiratory Tract Infections Flashcards

1
Q

what is the definition of pneumonia?

A

infection of the alveoli & surrounding lung

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2
Q

what is the definition of bronchitis?

A

inflammation of the large & mid-sized airways (bronchi)

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3
Q

are viruses or bacteria primarily responsible for most of bronchitis cases?

A

viruses

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4
Q

what is bronchiolitis?

A

inflammation of the bronchioles (smallest air passages of the lungs)

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5
Q

are viruses or bacteria primarily responsible for most cases of bronchiolitis?

A

viruses

RSV = 50-90%

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6
Q

what is acute pneumonia?

A

inflammation of the lungs d/t MICROBIAL INFECTION of the alveoli & surrounding lung

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7
Q

how long does acute pneumonia last?

A

days

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8
Q

what are the sx of atypical pneumonia?

A

moderate amt of sputum
no physical findings of consolidation
moderate WBC elevation
no alveolar exudates

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9
Q

what is chronic pneumonia?

A

inflammation of the lungs d/t microbial infection of the alveoli & surrounding lung OR non-infectious causes

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10
Q

how long does chronic pneumonia last?

A

weeks to months

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11
Q

what is pleural effusion & empyema?

A

accumulation of pus in the pleural cavity

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12
Q

what is a bacterial lung abscess?

A

infection causing necrosis of lung parenchyma

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13
Q

what are the 4 factors in development of pneumonia?

A
  1. defect in host defenses
  2. exposure to virulent microbe
  3. overwhelming inoculum
  4. a combo of these
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14
Q

what are the pulmonary host defenses in the nasopharynx?

A

nasal hair
anatomy of upper airways
mucociliary apparatus

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15
Q

what are the pulmonary host defenses in the oropharynx?

A

saliva
cough
bacterial interference

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16
Q

what are the pulmonary host defenses in the trachea & bronchi?

A

cough & epiglottal reflex
mucociliary apparatus
airway surface liquid

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17
Q

what are the airway surface liquid components?

A

lysozyme

lactoferrin

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18
Q

what are the pulmonary host defenses in the terminal airways & alveoli?

A

alveolar lining fluid
alveolar macrophages
neutrophil recruitment

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19
Q

what are the components of the alveolar lining fluid?

A

surfactant
fibronectin
iron binding proteins

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20
Q

what types of ALOC can impair pulmonary defenses?

A 
stroke
seizure
drugs
anesthesia
alcohol
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21
Q

how does ALOC impair pulmonary defenses?

A

compromises epiglottic closure st pt aspirates oropharyngeal flora

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22
Q

how does cigarette smoke impair pulmonary defenses?

A

disrupts mucociliary fxn

disrupts macrophages

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23
Q

how does alcohol abuse impair pulmonary defenses?

A

impairs cough & epiglottic reflexes
increased colonization of oropharynx w/ gram neg bacilli
decreased cellular responses

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24
Q

what type of bacteria colonize the oropharynx when the host pulmonary defenses are impaired?

A

gram negative bacilli

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25
how do M. pneumoniae, H. influenzae, & viruses impair pulmonary defenses?
interfere w/ or destroy cilia | defective cell fxn
26
what are the 3 iatrogenic mechanisms that bypass or interfere w/ pulmonary defenses?
endotracheal tubes nasogastric tubes respiratory therapy machinery
27
what age group is susceptible to impaired pulmonary defenses?
old farts
28
what are the 4 things that impair pulmonary defenses in old people?
1. inc # & severity of diseases 2. less effective mucociliary clearance & coughing 3. increased mucoaspiration 4. immune senescence
29
what are 3 underlying diseases that can impair pulmonary defenses (there are A LOT but these are the 3 listed)?
COPD immune deficiencies asplenia
30
what are the 7 pneumonia syndromes?
1. community-acquired acute 2. community-acquired atypical 3. hospital-acquired 4. aspiration 5. chronic 6. necrotizing & lung abscess 7. pneumonia in immunocompromised host
31
what are the 1st line pathogens assoc w/ community-acquired ACUTE pneumonia?
Strep pneumoniae Legionella pneumophila Klebsiella pneumoniae
32
what are the 2nd line pathogens assoc w/ community-acquired ACUTE pneumonia?
Haemophilus influenzae Staph aureus Pseudomonas
33
what are the 1st line pathogens assoc w/ community-acquired ATYPICAL pneumonia?
mycoplasma pneumoniae
34
what are the 2nd line pathogens assoc w/ community-acquired ATYPICAL pneumonia?
chlamydia (pneumoniae, psittaci, & trachomatis)
35
what are the 1st line pathogens assoc w/ hospital-acquired pneumonia?
Klebsiella sp | Legionella pneumophila
36
what are the 2nd line pathogens assoc w/ hospital-acquired pneumonia?
``` Pseudomonas sp Staph aureus (usu penicillin resistant) ```
37
what are the 1st line pathogens assoc w/ chronic pneumonia?
``` Nocardia Mycobacterium tb + atypical mycobacterium Histoplasma capsulatum Coccidioides immitis Blastomyces dermatitidis ```
38
what are the 1st line pathogens assoc w/ necrotizing pneumonia & lung abscesses?
klebsiella pneumoniae
39
what are the 2nd line pathogens assoc w/ necrotizing pneumonia & lung abscesses?
Staph aureus
40
what are the 1st line pathogens assoc w/ pneumonia in immunocompromised hosts?
pneumocystis jiroveci | mycobacterium avium-intracellulare
41
what is the exposure hx assoc w/ Legionnaires' disease?
contaminated aerosols (air coolers, hospital water supply)
42
what is the exposure hx assoc w/ anthrax?
goat hair, raw wool, animal hides
43
what is the exposure hx assoc w/ brucellosis?
ingestion of unpasteurized milk
44
what is the exposure hx assoc w/ histoplasmosis?
bat droppings (GUANO!!)(caves) or dust from soil enriched w/ bird droppings
45
what is the exposure hx assoc w/ leptospirosis?
water contaminated w/ animal urine
46
what is the exposure hx assoc w/ hantavirus?
rodent droppings, urine, saliva
47
what is the exposure hx assoc w/ anthrax, plague, & tularemia?
potential bioterrorism exposure
48
what is the possible zoonotic exposure assoc w/ brucellosis?
employment as abattoir or vet
49
what is the possible zoonotic exposure assoc w/ anthrax & brucellosis?
exposure to cattle, goats, pigs
50
what is the possible zoonotic exposure assoc w/ plague?
exposure to rodents in Africa or SW US
51
what is the possible zoonotic exposure assoc w/ tularemia?
hunting/exposure to rabbits, foxes, squirrels | bites from flies or ticks
52
what is the possible zoonotic exposure assoc w/ psittacosis?
exposure to birds
53
what is the possible zoonotic exposure assoc w/ pasteurella multocida & coxiella burnetii (Q fever)?
exposure to infected dogs & cats
54
what is the possible zoonotic exposure assoc w/ Q fever?
exposure to infected goats, cattle, sheep, domestic animals, & their secretions (milk, amniotic fluid, placenta, feces)
55
what is a possible travel exposure assoc w/ coccidioidomycosis?
``` San Joaquin Valley southern CA SW TX southern AZ NM ```
56
what is a possible travel exposure assoc w/ histoplasmosis & blastomycosis?
Mississippi or Ohio River Valleys Caribbean central America Africa
57
what is a possible travel exposure assoc w/ SARS & avian influenza?
china
58
what is a possible travel exposure assoc w/ MERS-CoV?
Arabian peninsula
59
what is a possible travel exposure assoc w/ melioidosis?
SE Asia W Indies Australia Guam
60
what is the pathogenesis of cystic fibrosis?
lung obstructed by viscous secretions
61
what causes airway wall damage in cystic fibrosis?
persistent bacterial infection
62
what are the 4 microbes assoc w/ CF?
1. staph aureus 2. pseudomonas aeruginosa 3. burkholderia cepacia complex 4. H. flu
63
what are the 3 treatment guidelines for CF?
1. REMOVE viscous & purulent airway SECRETIONS 2. control bacterial infection w/ ABX 3. provide proper nutrition for HOST DEFENSE
64
what things in a pt hx suggest pneumonia?
1. sx 2. clinical setting 3. defects in host defense 4. possible pathogen exposure
65
T/F: sensitivity & specificity of physical exam findings is high for pneumonia
``` FALSE relatively low (50-75%) ```
66
what 2 general things during physical exam can be suggestive of pneumonia?
systemic > fever | chest exam findings
67
what are the 5 diagnostic tests you can use for pneumonia?
1. radiology 2. examination of sputum 3. examination of pleural effusions 4. bronchoscopy 5. blood culture, serology, urine studies (incl ag detection)
68
what is the gold standard for making a clinical diagnosis of pneumonia?
Radiology!
69
what is the PRIMARY CAUSE of bacterial pneumonia & meningitis?
strep pneumo
70
what are the 4 characteristic sx of pneumococcal pneumonia?
abrupt onset fever sharp pleural pain bloody rusty sputum
71
T/F: pneumococcal pneumonia is a disease of otherwise healthy pts
FALSE | "a disease of compromised host > age, physical condition, genetics (sickle cell)"
72
where does pneumococcal pneumonia localize?
lower lobes | i.e. lobar pneumonia
73
have you gone over the other set of Kozel flash cards?
you should! (mainly for lab dx & pneumococcal vax)
74
what does treatment approach of pneumococcal pneumonia vary w/?
site of infection setting of infection pt condition
75
is klebsiella pneumoniae encapsulated?
YEP
76
how does klebsiella pneumoniae cause pneumonia?
necrotic destruction of alveolar spaces
77
what is the sputum like in klebsiella pneumonia?
thick bloody MUCOID!!!
78
T/F: pts w/ klebsiella pneumonia are usu compromised
TRUE | immunosuppressed or impaired respiratory defenses
79
what are the 4 other infections that klebsiella pneumoniae can cause?
UTI wound infection bacteremia meningitis
80
what is the 2nd most common cause of UTI among oldies after E. coli?
klebsiella pneumoniae
81
what is the colony morphology of klebsiella pneumoniae?
mucoid
82
what word should you associate w/ klebsiella pneumoniae?
MUCOID
83
what samples can you use for lab dx of klebsiella?
sputum blood pus CSF
84
how do you isolate klebsiella pneumoniae (medium)?
typical enteric medium
85
is klebsiella pneumoniae an enterobacter?
YES
86
how do you identify klebsiella on media?
fermenter mucoid colonies typical enteric differential media
87
T/F: healthy people get klebsiella pneumonia
FALSE | disease of SICKIES!
88
where is klebsiella mainly spread?
hospital
89
HOW is klebsiella spread?
person to person OR contamination of ventilators, IV catheters, wounds
90
how do you prevent klebsiella pneumonia?
strict attn to infection control measures
91
T/F: klebsiella is easily treated w/ abx
FALSE | highly resistant!
92
what are the 4 mechanisms of resistance of klebsiella?
1. overpdtion of beta lactamase 2. extended spectrum beta lactamases 3. efflux pump 4. carbapenem resistance
93
what is CRKP?
carbapenem-resistant klebsiella pneumoniae
94
what encodes carbapenem resistance?
blaKPC gene
95
what does CRKP do w/ beta lactam abx?
hydrolyzes ALL OF THEM
96
T/F: klebsiella pneumoniae is resistant to beta lactamase inhibitors
TRUE
97
what are the treatment options for CRKP?
polymyxins or sometimes nothing
98
what is treatment of klebsiella pneumoniae dependent on?
susceptibility testing | gotta find an abx that works
99
T/F: Legionella pneumophila stains really well
FALSE | stains poorly w/ common reagents
100
what 2 things does Legionella pneumophila require to grow?
cysteine | iron
101
where does Legionella pneumophila replicate?
inside macrophages
102
what does Legionella pneumophila do inside the macrophage?
prevents phagolysosome fusion
103
how many legionella species infect humans?
20
104
how many legionella species are there?
50+
105
what is Legionnaires' disease?
severe acute pneumonia
106
what are the sx of Legionnaires' disease?
fever non-pdtive cough SOB myalgias
107
what are the risk factors of Legionnaires' disease?
50+ yo smoker (now or previously) chronic lung disease weakened immune system, diabetes, kidney failure, immunosuppression
108
what is the mortality rate of Legionnaires' disease?
15-20% | this is high!
109
what is Pontiac fever?
mild form of respiratory infection | NOT pneumonia!
110
what causes Pontiac fever?
exposure to aerosol | high attack rate
111
what is the mortality of pontiac fever?
very low, <1%
112
what cells are infected in Legionnaires' disease?
alveolar macrophages monocytes alveolar epithelial cells
113
what does inhibiting phagolysosomal fusion prevent in Legionnaires' disease?
exposure to superoxide H2O2 & OH radicals (ROS)
114
what is the eventual immunity assoc w/ Legionnaires' disease?
cell-mediated
115
how do you dx Legionnaires' disease?
urinary ag test x-ray/physical exam to dx pneumonia expectorated sputum or endotracheal aspirate
116
what is the most commonly used dx tool in Legionnaires' disease?
urinary ag test
117
what does the urinary ag test detect for Legionnaires' disease?
serogroup 1 LPS
118
what serogroup is responsible for 80-90% of community acquired infections of Legionnaires' disease?
serogroup 1
119
what % of hospital-acquired infections are d/t serogroup 1?
<50%
120
T/F: culture of legionella pneumophilae requires special media
TRUE
121
where is legionella pneumophila found?
aqueous environments > warm water
122
what is the host of legionella pneumophila?
free-living amoebas
123
how do you acquire legionella pneumophila?
exposure to contaminated aerosols > air conditioning, cooling towers, hot tubs, misters, etc
124
T/F: legionnaires disease is common
true! | 20k-100k cases in US/yr (estimated)
125
is subclinical infection w/ legionella pneumophila common?
YES | indicated by serological testing
126
why is legionella pneumophila infection often hospital acquired?
high # of high-risk pts
127
how do you prevent & control legionnaires' disease?
routine surveillance for microbial burden | clean & disinfect as appropriate
128
do you do susceptibility tests for legionnaires' disease?
NOPE | bc it's too hard to grow the bacterium
129
why are many abx ineffective against legionnaires' disease?
bc they have poor penetration of macrophages
130
what abx can you use to treat legionnaires' disease?
macrolides > azithromycin fluoroquinolones > levofloxacin tetracyclines > doxy
131
how do you treat pontiac fever?
you don't
132
what is the smallest free-living bacterium?
mycoplasma
133
what is unique about mycoplasma's cell wall?
it doesn't have one | so it is RESISTANT to abx that target the cell wall
134
what does the cell membrane of mycoplasma contain?
sterols from the host | e.g. cholesterol
135
what does growth in culture of mycoplasma require?
medium containing sterols | e.g. animal serum
136
what is the pathogenesis of mycoplasma?
adheres to respiratory epithelium via attachment organelle > destroys cilia then ciliated epithelial cells > irritation & secondary infection
137
what causes a persistent cough w/ mycoplasma infection?
the irritation & secondary infection
138
what is the primary adhesin for mycoplasma?
P1 protein
139
where are the receptors for mycoplasma?
host cells
140
T/F: most infection w/ mycoplasma is asymptomatic
TRUE
141
what are the 2 clinical diseases assoc w/ mycoplasma?
tracheobronchitis | primary atypical pneumonia
142
what is the most common clinical disease assoc w/ mycoplasma?
tracheobronchitis
143
what are the sx of tracheobronchitis?
low-grade fever malaise HA non-productive cough
144
what is primary atypical pneumonia d/t mycoplasma like for the pt?
it's okay pts not terribly ill "walking pneumonia"
145
what is more impressive than clinical signs in mycoplasma primary atypical pneumonoia?
patchy bronchopneumonoia on chest radiograph
146
how is mycoplasma pneumonia usually diagnosed?
empirically, based on clinical signs
147
can you use microscopy for mycoplasma pneumoniae?
NOPE | and it stains poorly too
148
what does mycoplasma pneumoniae require for growth?
special media supplemented w/ serum (sterols) PLUS it grows really slow (2-6 weeks) so DON'T CULTURE IT
149
why don't you use serology to dx mycoplasma pneumoniae?
lacks sensitivity & specificity (both complement fixation & cold agglutinin)
150
how does cold agglutinin serology work?
IgM ab bind to I blood group ag on human RBCs at 4C
151
how is mycoplasma pneumoniae spread?
respiratory droplets
152
is mycoplasma pneumoniae zoonotic?
nope | strictly human
153
T/F: mycoplasma pneumoniae incidence is seasonal
FALSE
154
all populations are susceptible to mycoplasma pneumoniae, but what age group is primarily infected?
children 5-15 yo
155
what are the 3 best treatments for mycoplasma pneumonia?
macrolide (erythro/azithro) tetracycline (doxy) fluoroquinolone
156
which abx can you NOT use for kids that have mycoplasma pneumonia?
tetracyclines
157
which abx is most expensive to treat mycoplasma pneumonia?
$$$: fluoroquinolones | $: tetracyclines
158
what are the 5 types of endemic dimorphic fungi?
``` histoplasmosis blastomycosis coccidiomycosis paracoccidioidomycosis penicilliosis ```
159
where does histoplasma capsulatum live?
soil w/ lots of Nitrogen i.e. bird & bat poop
160
where is H. capsulatum found in the world?
OH & Mississippi river valleys | Mexico, C & S America
161
what is a major risk factor of H. capsulatum in S & C America & Mexico?
AIDS
162
where is H. capsulatum var. duboisii found in the world?
tropical Africa
163
what are the 4 steps of natural history of H. capsulatum?
1. inhale microconidia 2. germination into yeast 3. intracellular growth in lungs 4. stay local or disseminate
164
where does h. capsulatum grow in your body?
intracellular in the lungs
165
what is the primary host defense against histoplasmosis?
cellular immunity
166
what type of histoplasmosis is common in endemic areas?
acute pulmonary
167
what are the 4 types of histoplasmosis?
acute pulmonary chronic pulmonary progressive disseminated African
168
what are the sx of acute pulmonary histoplasmosis?
usu asymptomatic or flu-like | if sick, fever, HA, non-pdtive cough, chills, chest pain
169
what are the sx of chronic pulmonary histoplasmosis?
fever, pdtive cough, chest pain, CAVITARY LESIONS
170
what is affected in progressive disseminated histoplasmosis?
multiple organ systems
171
what are the risk factors for progressive disseminated histoplasmosis?
55+ yo | immunosuppression
172
what variant of histoplasma is implicated in African histoplasmosis?
h. capsulatum var. duboisii
173
what are the most commonly involved organ systems in African histoplasmosis?
skin & skeleton
174
what is the histopathology of histoplasmosis?
small budding yeasts w/i macrophages
175
does histoplasma display temp-dependent dimorphism?
YEP
176
what does histoplasma look like at 37 C?
yeast | small, oval, budding
177
what is the mycelium form of histoplasma (what does it look like at 20 C)?
tuberculate macroconidia
178
how does the ag immunoassay for histoplasmosis work?
detects cell wall polysaccharide (reference lab only)
179
what is the best sample for the ag immunoassay for histoplasmosis?
urine
180
how does serology for histoplasmosis work?
tests for serum ab via complement fixation or precipitation
181
what is the false seropositive rate of histoplasmosis in endemic areas?
10%
182
what % of pts w/ acute histoplasmosis develop the ab?
75%
183
what test has little value for diagnosing histoplasmosis but is useful for epidemiology?
skin test
184
what determines delayed hypersensitivity for histoplasmosis?
histoplasmin skin test
185
T/F: most cases of acute pulmonary histoplasmosis require no treatment
TRUE
186
what does the extent of treatment for histoplasmosis vary with?
severity of disease
187
what antifungals can you use for histoplasmosis?
itraconazole | amphotericin B or liposomal amphotericin B
188
where does blastomyces dermatitidis live?
soil w/ decaying organic matter
189
where is blastomyces dermatitidis found geographically?
OH & Mississippi river valleys | SE US
190
what does the endemic area of blastomyces dermatitidis overlap w/?
histoplasmosis
191
how does blastomyces dermatitidis get into your body?
inhalation of conidia from environmental site
192
what is the natural hx of blastomyces dermatitidis?
1. inhale conidia 2. germinate into yeast 3. grow in lungs 4. remain local or disseminate
193
what animal is highly susceptible to blastomyces dermatitidis infection?
dogs | but they are NOT a reservoir
194
what is the primary host defense against blastomycosis?
cellular immunity
195
what are the 3 types of blastomycosis?
acute pulmonary disseminated infection in immunocompromised host
196
what % of cases of acute pulmonary blastomycosis are asymptomatic?
50%
197
what is the clinical course of acute pulmonary blastomycosis?
asymptomatic but may progress to fulminant respiratory disease w/ abrupt onset of myalgia, arthralgia, chill, fever
198
what is most often involved in disseminated blastomycosis?
skin
199
what sites may also be affected in disseminated blastomycosis?
``` lymph nodes bones joints prostate CNS ```
200
what does infection of blastomycosis in an immunocompromised host look like?
aggressive! but less common than other fungi
201
what is the histopathology of blastomycosis?
broad-based large budding yeasts
202
what does blastomycosis look like at 20C?
non-specific mycelium
203
what does blastomycosis look like at 37C?
small oval broad-based budding yeasts
204
how do you confirm blastomycosis culture?
PCR
205
what 2 tests are USEFUL in diagnosing blastomycosis?
culture | ag immunoassay of urine
206
what does the ag immunoassay of urine detect in blastomycosis?
detects cell wall polysaccharide (reference lab only) but it's LOW SPECIFICITY bc it's cross-reactive w/ other fungi
207
what meds can you use to treat blastomycosis?
itraconazole | lipid amp-B
208
what med should you use for mild/moderate blastomycosis?
itraconazole
209
what med should you use for severe blastomycosis or blastomycosis in an immunocompromised pt?
lipid amp-B
210
what does coccidioides immitis look like in soil?
mycelium w/ "barrel shaped" arthroconidia
211
what does coccidioides immitis look like in tissue?
endosporulating spherules
212
what does coccidioides immitis live in?
soil of dry, low-rainfall areas
213
what is the geographic distribution of coccidioides immitis?
SW US (CA, AZ, NM) Mexico C & S America
214
there are 2 species of coccidioides. are they distinguishable?
nope
215
what species of coccidioides is in California?
immitis
216
what species of coccidioides is found in all infectious OUTSIDE of California?
posadasii
217
what is the natural history of coccidioides immitis?
inhale arthroconidia > germinate in lungs > form spherules > stay local or disseminate
218
what is valley fever?
coccidioidomycosis
219
what is the primary host defense against coccidioidomycosis?
cellular immunity
220
what are the 3 types of coccidioidomycosis?
primary pulmonary pulmonary nodules & cavities extrapulmonary dissemination
221
in endemic areas, what % of ppl have primary pulmonary coccidioidomycosis?
30-60%
222
how long after exposure do you get symptoms of coccidioidomycosis?
7-21 days (1-3 weeks)
223
what are the sx of coccidioidomycosis?
``` cough chest pain SOB fever fatigue ```
224
what % of pulmonary coccidioidomycosis infections get pulmonary nodules & cavities?
4%
225
what are the sx of pulmonary nodules & cavities of coccidioidomycosis?
pleuritic pain cough hemoptysis
226
in 0.5% of the general pop that gets primary coccidioidomycosis infection progresses to what?
extrapulmonary dissemination
227
what are the risk factors for extrapulmonary coccidioidomycosis dissemination?
immunosuppression | genetics (African or Filipino descent)
228
what is the most serious form of extrapulmonary coccidioidomycosis dissemination?
coccidioidal meningitis
229
what establishes diagnosis of coccidioidomycosis?
endosporulating spherules in sputum, exudates, or tissue
230
can you culture coccidioides?
you can, but it's less useful than other fungi AND it's an EXTREME BIOHAZARD!
231
is the mycelium form of coccidioides specific?
no | but it does have characteristic arthroconidia (?)
232
what test can be useful in diagnosing coccidioidomycosis in pts w/ non-pdtive cough?
serology > tests for serum ab
233
what % of pts w/ acute coccidioidomycosis develop ab?
75%
234
what % of normal ppl are positive for coccidioidomycosis in endemic areas?
10%
235
what test is useful for epidemiology but not for diagnosis of coccidioidomycosis?
coccidioidin skin test
236
what does coccidioidin skin test determine?
delayed hypersensitivity
237
what are the treatments for coccidioidomycosis?
``` oral azole (fluconazole, itraconazole, ketoconazole) amp-B ```
238
why is pneumocystis classified as a fungus?
rRNA sequences
239
what does pneumocystis lack?
ergosterol
240
what species of pneumocystis lives in rats?
carinii
241
what species of pneumocystis lives in humans?
jirovecii
242
is there an in vitro culture system for pneumocystis?
nope
243
T/F: the life cycle of pneumocystis is sexual only
FALSE | has sexual & asexual components
244
which microbial forms of pneumocystis are found during human infection?
all of them (trophic, sporozoite, & spores)
245
what microbial form of pneumocystis is "free"?
trophic
246
what microbial form of pneumocystis is precystic?
sporozoite
247
what do pneumocystis cysts contain?
up to 8 intracystic bodies
248
what are the 3 microbial forms of pneumocystis?
free (trophic) sporozoite (precystic) cysts (spores)
249
is natural resistance to pneumocystis high or low?
high
250
what happens if a host is compromised and infected w/ pneumocystis?
organisms proliferate & gradually fill alveolar lumens
251
what happens in the alveoli w/ pneumocystis infection?
foamy exudate in alveolar space AND intense interstitial infiltrate of plasma cells
252
what does pneumocystis infection progress to after alveolar infiltration?
interstitial fibrosis | edema
253
what classical presentation of pneumocystis occurs in debilitated infants?
interstitial plasma cell pneumonitis
254
what sx do immunosuppressed pts get w/ pneumocystis pneumonia?
SOB fever non-pdtive cough
255
what sx do HIV pts get w/ pneumocystis pneumonia?
similar to immunosuppressed presentation but SUBTLE
256
what sx do infants get w/ pneumocystis pneumonia?
insidious onset respiratory distress cyanosis
257
why is the mortality rate of PCP high if untreated?
respiratory failure
258
how do you dx PCP?
empirically via clinical signs in an immunosuppressed pt or microscopy
259
what is most useful in diagnosing PCP?
microscopy
260
what is the sensitivity of BAL fluid staining for PCP?
90-100%
261
what forms does the Wright-Giemsa stain work on for PCP?
all forms
262
what stain can you use for the cyst form?
silver stain
263
what does the cyst form stain look like?
(silver stain) | crushed ping pong ball
264
what age does ubiquitous colonization of pneumocystis occur at?
early in life, first 2 years
265
how is pneumocystis communicable (what route)?
airborne
266
how does immunocompromise allow for pneumocystis infection?
reactivation of latent infection OR progression of recently acquired infection
267
what are the risk factors for PCP?
``` malnourished/preemie babies SCID hyper-IgM syndrome immunosuppressive meds AIDS ```
268
what has made PCP less frequent in AIDS pts?
HAART
269
what is the tx for PCP?
TMP-SMZ (prophylaxis AND treatment)
270
who should you use chemophrophylaxis for against PCP?
AIDS pts w/ CD4 counts <200/mm3
271
who discovered mycobacteria?
Koch
272
what does mycobacteria have in the cell wall?
mycolic acid
273
what are mycolic acids?
long fatty acids
274
what properties do mycolic acids confer to mycobacteria?
``` acid-fast resistant to gram stain resistant to detergents & hydrophobic abx survive in macrophages "cording" arrangement ```
275
how is the cell wall structure of mycobacteria like a gram+?
inner membrane thick peptidoglycan layer NO outer membrane
276
how the cell wall structure of mycobacteria NOT like gram+?
LAM | additional lipids
277
what is LAM?
lipoarabinomannan | functionally similar to O-ag
278
how much of the cell wall weight (%) of mycobacteria is d/t lipids?
60%
279
what causes TB?
m. tuberculosis complex
280
what are the 5 components of the m. tuberculosis complex?
m. tuberculosis m. bovis bacille Calmette-Guerin m. africanum m. canetti
281
what species cause TB in Africa?
m. africanum (duh) | m. canetti
282
what species causes TB in cattle?
m. bovis
283
how is m. bovis spread to humans?
eating/drinking contaminated dairy products
284
what is bacille calmette-guerin?
less virulent strain of m. bovis
285
what is the mycobacteria species that is not part of the m. tuberculosis complex?
m. leprae
286
what is another name for atypical mycobacteria?
non-TB mycobacteria
287
what is cord factor?
trehalose dimycolate subset of cell wall mycolic acids glycolipid cell wall component
288
where can you find cord factor?
in the cell wall of VIRULENT STRAINS
289
what does cord factor bind to?
macrophage surface receptor called MINCLE (minkus!)
290
what does cord factor do once it binds (3 things)?
blocks macrophage activation by IFN-gamma induces secretion of TNF-alpha causes cord formation
291
is tuberculosis intra or extracellular?
INTRACELLULAR
292
what must tuberculosis avoid being killed by?
macrophages
293
what are the 2 types of TB?
primary | reactivated
294
how does reactivation TB happen?
waning/loss of cellular immunity allows for bacterial outgrowth
295
what is the response to reactivation TB?
destructive delayed-type hypersensitivity
296
in primary TB, what phagocytizes the bacteria?
alveolar macrophages
297
how does primary TB survive in the body?
prevents fusion of phagosome w/ lysosome (in macrophage)
298
what happens to infected macrophages in primary TB?
secrete cytokines (IL-12 & TNF-alpha)
299
what do the cytokines from primary TB-infected macrophages drive?
drive T cells to differentiate into Th1 cells that secrete IFN-gamma
300
in primary TB, what does IFN-gamma do?
activates infected macrophages | promotes phagosome-lysosome fusion & killing via ROS & RNS
301
in primary TB, what can the delayed-type hypersensitivity response lead to?
granuloma
302
what is a primary TB granuloma composed of (5 things)?
``` lymphocytes macrophages epithelioid cells fibroblasts giant cells ```
303
how is primary TB resolved?
either the bacteria go dormant or you have to kill them
304
what are the sx of primary TB?
usu asymptomatic | OR can be mild fever & malaise
305
what can you see on radiographs of primary TB?
mid-lung infiltrates | hilar lymphadenopathy
306
what 2 things can primary TB progress to?
reactivation | dissemination
307
what % of pts w/ primary TB reactivate?
10%
308
what pt population gets reactivation TB?
men 50+yo
309
what disease is reactivation TB most often assoc w/?
immunosuppression | AIDS is most common
310
what are the sx of reactivation TB?
``` dry cough that becomes productive & mixed w/ blood (hemoptysis) fever malaise sweating weight loss ```
311
what do the lungs look like in reactivation TB?
cavities in apices (it rhymes!) | cavities have TONS of bacteria
312
what happens if you don't treat reactivation TB?
death in 2-5 years
313
what disorders can lead to a more rapid course of reactivation TB?
AIDS | other T cell compromise
314
make sure you look at SLIDE 69 > extrapulmonary TB bc idk how to make a card about it
okie dokie
315
what allows for a presumptive dx of TB?
radiology
316
why is radiology important w/ TB?
central to dx asses extent & character of disease evaluate response to tx
317
on radiology, what is highly suggestive of TB?
patchy or nodular infiltrate in the lung apices, esp if the infiltrate is cavitary
318
what are the 2 things you can do to immunodiagnose TB?
skin test | IFN-gamma-release assay
319
what can you do on microscopy to dx TB?
acid-fast stain
320
when you do a TB skin test, what do you inject & where do you inject it?
INTRADERMAL injection of 5 tuberculin units of PPD
321
what is PPD?
purified protein derivative | cell wall protein
322
how long after the injection should you look at the skin site?
48-72 hours
323
what are you looking for w/ a TB skin test?
INDURATION | NOT ERYTHEMA!
324
what are the 3 cutoffs in size of the TB skin test reaction?
5 mm cutoff for immunosuppressed or recent contacts 10 mm cutoff for other high risk groups 15 mm cutoff for low risk groups
325
what does a positive TB skin test imply?
``` INFECTION NOT DISEASE (necessarily)!!! ```
326
what can cause a false positive TB skin test?
infection w/ non-mycobacterium TB mycobacteria (non-Mtb)
327
what can cause a false negative TB skin test?
generalized illness or immunosuppression
328
what are not necessarily recommended for negative skin TB tests, even though they can identify anergy?
additional skin tests w/ candida or mumps ag
329
how can you identify cell mediated immunity to TB (what test)?
IFN-gamma release assay
330
how do you do the IFN-gamma release assay?
incubate whole blood w/ Mtb ag | measure the release of IFN-gamma
331
what are the antigens in the IFN-gamma release assay (generally)?
3 Mtb proteins NOT FOUND in NON-Mtb species
332
what are the 3 advantages to the IFN-gamma release assay?
no rxn in ppl who received BCG no need to return to have skin test eval no booster effect w/ repeat testing
333
what are the 2 disadvantages to the IFN-gamma release assay?
$$$$$ | lab infrastructure
334
what is now recommended by the CDC to detect Mt infection & surveillance?
IFN-gamma release assay
335
what do you do with a smear of a suspected TB sample?
``` cover w/ stain heat it up rinse decolorize w/ acid alcohol counterstain w/ methylene blue ```
336
what conc is required for Mtb positivity on a slide?
10,000 Mtb/mL is positive >/= 10 Mtb on a slide = optimal a single organism is highly suggestive
337
what dyes are the most sensitive for Mtb?
fluorescent
338
what should you use in resource limited countries to dx TB?
LED microscopes
339
what stain is hot acid fast?
Ziehl-Nielsen (cause Zayn is the hottest dude in one direction)
340
what stain is cold acid fast?
Kinyoun (Kin cold)
341
what stain is fluorochrome acid fast?
Truant (T & F both have crosses)
342
how do nucleic acid-based tests for TB work?
PCR amplification of a clinical sample
343
what is the sensitivity of nucleic-acid based tests (compared to other diagnostic tools, not a number)?
intermediate btwn acid fast & culture
344
what are the 2 advantages to the nucleic acid-based tests for TB?
simultaneously assess resistance to RIFAMPIN (surrogate for MDR) AND can be self-contained (Cephid) > advantage for resource-limited countries
345
what are the 3 disadvantages of nucleic acid-based tests for TB?
sensitivity & ease of use varies some tests require advanced lab infrastructure too $$$ for resource-limited
346
what is the GOLD STANDARD for TB dx?
CULTURE!
347
what can culture of TB detect (concentration)?
10-100 Mtb/mL (which is a lower conc than acid fast so it's BETTER than acid fast)
348
what do samples from contaminated sites require?
decontamination
349
can mycobacteria survive decontamination?
yes | mild decontamination
350
what are the 2 culture media for TB?
solid AND liquid
351
what are the 2 types of solid culture media for TB?
Lowenstein-Jensen | Middlebrook
352
how long does TB culture on solid medium take?
3-8 weeks
353
how long does TB culture on liquid medium take?
1-3 weeks
354
how can you identify TB cultures?
colony morphology biochemical tests species-specific molecular probes
355
what are the 3 ways to detect abx sensitivity of TB?
agar proportion liquid broth systems molecular tests
356
how does the agar proportion for TB abx sensitivity work?
determines percentage of resistant Mtb
357
why are the liquid broth systems for TB abx sensitivity good?
provide FASTER results
358
what do the molecular tests for TB abx sensitivity detect?
resistance to RIFAMPIN
359
what % of the world's population is infected w/ TB?
33% (1/3)
360
how many new cases & deaths does TB cause annually?
9 million new cases | 2 million deaths
361
how many new cases of TB are there in the US per year?
11,000
362
most cases of TB in the US are what kind of TB?
reactivation | most are foreign-born
363
how is TB spread?
person-to-person (humans ONLY) via airborne droplets
364
how are most TB infections dealt with in the body (very generally)?
immune system
365
who is at risk of exposure to TB via close contact?
healthcare workers | "institutional exposure"
366
exposure to TB depends on what 2 things?
closeness of contact | infectiousness of source (i.e. cavitary TB)
367
what is the biggest risk factor for TB?
immunosuppression
368
what are the 4 first line drugs used in combo for TB treatment?
``` isoniazid rifampin ethambutol pyrazinamide (IREP) ```
369
how does isoniazid work?
inhibits synthesis of mycolic acid
370
how does rifampin work?
inhibits DNA-dependent RNA polymerase
371
how does ethambutol work?
inhibits cell wall synthesis
372
how does pyrazinamide work?
who knows | "mechanism not well understood"
373
what "other agents" does Kozel list that you can also use to treat TB?
aminoglycosides | fluoroquinolones
374
how do you combat the emergence of abx resistance in TB?
use 4 drugs
375
what are the 2 other treatment things you can do for TB?
directly-observed treatment | consulting current guidelines
376
what is MDR TB resistant to?
at least | isoniazid AND rifampin
377
in what population was MDR TB first observed?
in AIDS & homeless people in NYC & Miami
378
what causes MDR TB?
interrupted abx course | drug levels insufficient to kill 100% of bacteria
379
what is XDR TB?
EXTENSIVELY drug resistant TB
380
how does XDR TB start?
as MDR TB
381
what is XDR TB resistant to?
``` isoniazid rifampin quinolones AND at least 1 second-line drug ```
382
where can you find XDR TB?
most regions of the world
383
can you treat XDR TB?
maybe? | "potentially untreatable"
384
what is the BCG vaccine?
LIVE vaccine of Bacille Calmette-Guerin (less virulent strain of M. bovis)
385
how many people got BCG vaccine?
3-5 BILLION | more than any other vaccine
386
who gets the BCG vax?
infants in endemic countries | NOT in the US or other countries w/ low incidence of TB
387
what positive effect has the BCG vax had?
reduced incidence of disseminated TB in kids
388
what does the BCG vax do with the TB skin test?
produces false-positive | but skin test reactivity is low
389
what does BCG NOT consistently reduce?
incidence of adult pulmonary disease
390
what can happen if you give the BCG vax to pts w/ primary or acquired immune deficiency (AIDS)?
BCG disease | but not autism!
391
are non-TB mycobacteria (NTM) & atypical mycobacteria the same thing?
yup
392
how do you classify NTM?
growth rate | pigmentation (Runyon)
393
what are the 5 major disease producing species of NTM?
``` M. kansasii M. fortuitum M. abscessum M. ulcerans M. marinum (how fortuitous that in kansas, you can get an abscess and an ulcer at the marina) ```
394
how do you get NTM?
environmental sources i.e. tap water
395
how many species TOTAL are there of NTM that cause disease?
>50
396
what diseases/syndromes can result from NTM?
1. chronic bronchopulmonary disease 2. skin & soft tissue disease 3. lymphadenitis 4. disseminated disease in immunosuppressed pts (AIDS)
397
how do you dx NTM?
same as Mtb
398
how do you treat NTM?
it depends on the species | "tx varies dramatically w/ various NTM species"
399
which NTM has a high degree of abx resistance?
m. abscessum
400
what are the abx resistance mechanisms of m. abscessum?
abx modifying enzymes abx degrading enzymes target modification efflux pumps
401
what abx is m. abscessum resistant to via abx modifying enzymes?
aminoglycosides
402
what abx is m. abscessum resistant to via abx degrading enzymes?
beta lactams
403
what abx is m. abscessum resistant to via target modification?
macrolides
404
how do you treat m. abscessum?
long-term abx | surgical intervention to drain any lesions
405
what case study is assoc w/ m. abscessum?
medical tourism for cosmetic surgery in the dominican republic
406
what are the 2 species in the mycobacterium avium complex (MAC)?
m. avium m. intracellulare (birds INSIDE a birdcage)
407
what are the 4 diseases assoc w/ MAC?
1. primary infection 2. chronic localized pulmonary disease 3. disseminated disease in advanced AIDS 4. cervical lymphadenitis
408
can you get reactivation disease w/ MAC?
NOPE
409
what kinds of pts get chronic localized pulmonary disease d/t MAC?
pts have intact immunity smokers COPD pts
410
which AIDS pts get disseminated disease?
the ones w/ CD4 <100/mm3 | it was very common prior to HAART
411
is microscopy for MAC good?
nope | lacks sensitivity & specificity
412
can you culture MAC?
yep | PLUS blood culture for disseminated disease
413
how do you get MAC?
from the environment via inhalation or ingestion
414
T/F: MAC spreads via person-to-person transmission
FALSE | none of that
415
what environmental sources can harbor MAC?
natural water sources indoor water systems pools hot tubs (great)
416
T/F: treating MAC is easy peasy lemon squeezy
FALSE very difficult! high treatment failure rate!
417
what abx can you use for MAC?
``` clarithromycin or azithro PLUS ethambutol PLUS rifabutin (C you in the ER cause you got MAC) ```
418
what should you do for pts if they have a CD4 <50 cells/mm2?
azithromycin prophylaxis for MAC
419
T/F: Nocardia is WEAKLY acid fast
TRUE
420
what shape is Nocardia?
filamentous rods
421
what species of Nocardia should you be worried about?
Nocardia asteroides complex (asteroides, brasiliensis) Rhodococcus Gordonia Tsukamurella
422
which Nocardia species are RARE and implicated in opportunistic infections?
Gordonia | Tsukamurella
423
which species of Nocardia is uncommon and involved in pulmonary, cutaneous, and CNS disease?
Rhodococcus
424
what is the virulence of nocardia related to?
ability to avoid intracellular killing
425
what inactivates the toxic metabolites of nocardia?
catalase | superoxide dismutase
426
what does cord factor do in nocardia?
prevents intracellular killing | prevents phagosome-lysosome fusion
427
what 2 disease classes can Nocardia cause?
bronchopulmonary | cutaneous
428
who gets bronchopulmonary nocardia disease?
immunocompromised pts
429
what is the course of bronchopulmonary nocardia infection?
disseminates to the CNS or skin
430
what is a mycetoma?
cutaneous Nocardia infection involving chronic granulomatous destruction of extremities
431
how can cutaneous nocardia manifest?
mycetoma lymphocutaneous infection cellulitis subQ abscess
432
what does nocardia in sputum look like?
beaded filaments!
433
how do you distinguish Nocardia from actinomyces?
ACID-FAST STAIN! | Nocardia is weakly acid fast
434
how do you culture Nocardia?
special media | notify lab
435
what does nocardia look like on agar culture?
aerial hyphae (looks like cotton)
436
when you do a molecular analysis of nocardia, what are you doing?
sequencing the rRNA
437
where is nocardia ubiquitous?
soil that has organic matter
438
how do you get nocardiosis?
inoculation of skin or inhallation
439
who gets nocardiosis?
mostly immunocompromised pts
440
what is the primary abx for nocardiosis?
TMP-SMX
441
how do you treat nocardiosis in an immunocompromised pt?
TMP-SMX PLUS amikacin OR imipenem OR broad-spectrum cephalosporin
442
how long do you treat nocardiosis for?
12 months!
443
how can you treat a really extensive nocardia infection?
surgical mgmt
444
FUCK YEAH YOU JUST WENT THROUGH 443 CARDS ABOUT FUCKING STUPID ASS BACTERIA!
YOU DID IT! YOU'RE AMAZING!

Block 9 Week 3 (8 decks)

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