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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
Q

how do M. pneumoniae, H. influenzae, & viruses impair pulmonary defenses?

A

interfere w/ or destroy cilia

defective cell fxn

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26
Q

what are the 3 iatrogenic mechanisms that bypass or interfere w/ pulmonary defenses?

A

endotracheal tubes
nasogastric tubes
respiratory therapy machinery

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27
Q

what age group is susceptible to impaired pulmonary defenses?

A

old farts

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28
Q

what are the 4 things that impair pulmonary defenses in old people?

A
  1. inc # & severity of diseases
  2. less effective mucociliary clearance & coughing
  3. increased mucoaspiration
  4. immune senescence
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29
Q

what are 3 underlying diseases that can impair pulmonary defenses (there are A LOT but these are the 3 listed)?

A

COPD
immune deficiencies
asplenia

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30
Q

what are the 7 pneumonia syndromes?

A
  1. community-acquired acute
  2. community-acquired atypical
  3. hospital-acquired
  4. aspiration
  5. chronic
  6. necrotizing & lung abscess
  7. pneumonia in immunocompromised host
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31
Q

what are the 1st line pathogens assoc w/ community-acquired ACUTE pneumonia?

A

Strep pneumoniae
Legionella pneumophila
Klebsiella pneumoniae

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32
Q

what are the 2nd line pathogens assoc w/ community-acquired ACUTE pneumonia?

A

Haemophilus influenzae
Staph aureus
Pseudomonas

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33
Q

what are the 1st line pathogens assoc w/ community-acquired ATYPICAL pneumonia?

A

mycoplasma pneumoniae

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34
Q

what are the 2nd line pathogens assoc w/ community-acquired ATYPICAL pneumonia?

A

chlamydia (pneumoniae, psittaci, & trachomatis)

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35
Q

what are the 1st line pathogens assoc w/ hospital-acquired pneumonia?

A

Klebsiella sp

Legionella pneumophila

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36
Q

what are the 2nd line pathogens assoc w/ hospital-acquired pneumonia?

A 
Pseudomonas sp
Staph aureus (usu penicillin resistant)
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37
Q

what are the 1st line pathogens assoc w/ chronic pneumonia?

A 
Nocardia
Mycobacterium tb + atypical mycobacterium
Histoplasma capsulatum
Coccidioides immitis
Blastomyces dermatitidis
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38
Q

what are the 1st line pathogens assoc w/ necrotizing pneumonia & lung abscesses?

A

klebsiella pneumoniae

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39
Q

what are the 2nd line pathogens assoc w/ necrotizing pneumonia & lung abscesses?

A

Staph aureus

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40
Q

what are the 1st line pathogens assoc w/ pneumonia in immunocompromised hosts?

A

pneumocystis jiroveci

mycobacterium avium-intracellulare

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41
Q

what is the exposure hx assoc w/ Legionnaires’ disease?

A

contaminated aerosols (air coolers, hospital water supply)

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42
Q

what is the exposure hx assoc w/ anthrax?

A

goat hair, raw wool, animal hides

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43
Q

what is the exposure hx assoc w/ brucellosis?

A

ingestion of unpasteurized milk

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44
Q

what is the exposure hx assoc w/ histoplasmosis?

A

bat droppings (GUANO!!)(caves) or dust from soil enriched w/ bird droppings

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45
Q

what is the exposure hx assoc w/ leptospirosis?

A

water contaminated w/ animal urine

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46
Q

what is the exposure hx assoc w/ hantavirus?

A

rodent droppings, urine, saliva

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47
Q

what is the exposure hx assoc w/ anthrax, plague, & tularemia?

A

potential bioterrorism exposure

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48
Q

what is the possible zoonotic exposure assoc w/ brucellosis?

A

employment as abattoir or vet

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49
Q

what is the possible zoonotic exposure assoc w/ anthrax & brucellosis?

A

exposure to cattle, goats, pigs

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50
Q

what is the possible zoonotic exposure assoc w/ plague?

A

exposure to rodents in Africa or SW US

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51
Q

what is the possible zoonotic exposure assoc w/ tularemia?

A

hunting/exposure to rabbits, foxes, squirrels

bites from flies or ticks

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52
Q

what is the possible zoonotic exposure assoc w/ psittacosis?

A

exposure to birds

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53
Q

what is the possible zoonotic exposure assoc w/ pasteurella multocida & coxiella burnetii (Q fever)?

A

exposure to infected dogs & cats

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54
Q

what is the possible zoonotic exposure assoc w/ Q fever?

A

exposure to infected goats, cattle, sheep, domestic animals, & their secretions (milk, amniotic fluid, placenta, feces)

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55
Q

what is a possible travel exposure assoc w/ coccidioidomycosis?

A 
San Joaquin Valley
southern CA
SW TX
southern AZ
NM
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56
Q

what is a possible travel exposure assoc w/ histoplasmosis & blastomycosis?

A

Mississippi or Ohio River Valleys
Caribbean
central America
Africa

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57
Q

what is a possible travel exposure assoc w/ SARS & avian influenza?

A

china

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58
Q

what is a possible travel exposure assoc w/ MERS-CoV?

A

Arabian peninsula

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59
Q

what is a possible travel exposure assoc w/ melioidosis?

A

SE Asia
W Indies
Australia
Guam

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60
Q

what is the pathogenesis of cystic fibrosis?

A

lung obstructed by viscous secretions

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61
Q

what causes airway wall damage in cystic fibrosis?

A

persistent bacterial infection

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62
Q

what are the 4 microbes assoc w/ CF?

A
  1. staph aureus
  2. pseudomonas aeruginosa
  3. burkholderia cepacia complex
  4. H. flu
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63
Q

what are the 3 treatment guidelines for CF?

A
  1. REMOVE viscous & purulent airway SECRETIONS
  2. control bacterial infection w/ ABX
  3. provide proper nutrition for HOST DEFENSE
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64
Q

what things in a pt hx suggest pneumonia?

A
  1. sx
  2. clinical setting
  3. defects in host defense
  4. possible pathogen exposure
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65
Q

T/F: sensitivity & specificity of physical exam findings is high for pneumonia

A 
FALSE
relatively low (50-75%)
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66
Q

what 2 general things during physical exam can be suggestive of pneumonia?

A

systemic > fever

chest exam findings

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67
Q

what are the 5 diagnostic tests you can use for pneumonia?

A
  1. radiology
  2. examination of sputum
  3. examination of pleural effusions
  4. bronchoscopy
  5. blood culture, serology, urine studies (incl ag detection)
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68
Q

what is the gold standard for making a clinical diagnosis of pneumonia?

A

Radiology!

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69
Q

what is the PRIMARY CAUSE of bacterial pneumonia & meningitis?

A

strep pneumo

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70
Q

what are the 4 characteristic sx of pneumococcal pneumonia?

A

abrupt onset
fever
sharp pleural pain
bloody rusty sputum

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71
Q

T/F: pneumococcal pneumonia is a disease of otherwise healthy pts

A

FALSE

“a disease of compromised host > age, physical condition, genetics (sickle cell)”

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72
Q

where does pneumococcal pneumonia localize?

A

lower lobes

i.e. lobar pneumonia

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73
Q

have you gone over the other set of Kozel flash cards?

A

you should! (mainly for lab dx & pneumococcal vax)

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74
Q

what does treatment approach of pneumococcal pneumonia vary w/?

A

site of infection
setting of infection
pt condition

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75
Q

is klebsiella pneumoniae encapsulated?

A

YEP

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76
Q

how does klebsiella pneumoniae cause pneumonia?

A

necrotic destruction of alveolar spaces

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77
Q

what is the sputum like in klebsiella pneumonia?

A

thick
bloody
MUCOID!!!

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78
Q

T/F: pts w/ klebsiella pneumonia are usu compromised

A

TRUE

immunosuppressed or impaired respiratory defenses

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79
Q

what are the 4 other infections that klebsiella pneumoniae can cause?

A

UTI
wound infection
bacteremia
meningitis

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80
Q

what is the 2nd most common cause of UTI among oldies after E. coli?

A

klebsiella pneumoniae

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81
Q

what is the colony morphology of klebsiella pneumoniae?

A

mucoid

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82
Q

what word should you associate w/ klebsiella pneumoniae?

A

MUCOID

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83
Q

what samples can you use for lab dx of klebsiella?

A

sputum
blood
pus
CSF

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84
Q

how do you isolate klebsiella pneumoniae (medium)?

A

typical enteric medium

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85
Q

is klebsiella pneumoniae an enterobacter?

A

YES

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86
Q

how do you identify klebsiella on media?

A

fermenter
mucoid colonies
typical enteric differential media

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87
Q

T/F: healthy people get klebsiella pneumonia

A

FALSE

disease of SICKIES!

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88
Q

where is klebsiella mainly spread?

A

hospital

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89
Q

HOW is klebsiella spread?

A

person to person
OR
contamination of ventilators, IV catheters, wounds

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90
Q

how do you prevent klebsiella pneumonia?

A

strict attn to infection control measures

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91
Q

T/F: klebsiella is easily treated w/ abx

A

FALSE

highly resistant!

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92
Q

what are the 4 mechanisms of resistance of klebsiella?

A
  1. overpdtion of beta lactamase
  2. extended spectrum beta lactamases
  3. efflux pump
  4. carbapenem resistance
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93
Q

what is CRKP?

A

carbapenem-resistant klebsiella pneumoniae

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94
Q

what encodes carbapenem resistance?

A

blaKPC gene

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95
Q

what does CRKP do w/ beta lactam abx?

A

hydrolyzes ALL OF THEM

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96
Q

T/F: klebsiella pneumoniae is resistant to beta lactamase inhibitors

A

TRUE

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97
Q

what are the treatment options for CRKP?

A

polymyxins or sometimes nothing

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98
Q

what is treatment of klebsiella pneumoniae dependent on?

A

susceptibility testing

gotta find an abx that works

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99
Q

T/F: Legionella pneumophila stains really well

A

FALSE

stains poorly w/ common reagents

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100
Q

what 2 things does Legionella pneumophila require to grow?

A

cysteine

iron

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101
Q

where does Legionella pneumophila replicate?

A

inside macrophages

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102
Q

what does Legionella pneumophila do inside the macrophage?

A

prevents phagolysosome fusion

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103
Q

how many legionella species infect humans?

A

20

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104
Q

how many legionella species are there?

A

50+

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105
Q

what is Legionnaires’ disease?

A

severe acute pneumonia

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106
Q

what are the sx of Legionnaires’ disease?

A

fever
non-pdtive cough
SOB
myalgias

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107
Q

what are the risk factors of Legionnaires’ disease?

A

50+ yo
smoker (now or previously)
chronic lung disease
weakened immune system, diabetes, kidney failure, immunosuppression

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108
Q

what is the mortality rate of Legionnaires’ disease?

A

15-20%

this is high!

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109
Q

what is Pontiac fever?

A

mild form of respiratory infection

NOT pneumonia!

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110
Q

what causes Pontiac fever?

A

exposure to aerosol

high attack rate

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111
Q

what is the mortality of pontiac fever?

A

very low, <1%

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112
Q

what cells are infected in Legionnaires’ disease?

A

alveolar macrophages
monocytes
alveolar epithelial cells

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113
Q

what does inhibiting phagolysosomal fusion prevent in Legionnaires’ disease?

A

exposure to superoxide H2O2 & OH radicals (ROS)

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114
Q

what is the eventual immunity assoc w/ Legionnaires’ disease?

A

cell-mediated

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115
Q

how do you dx Legionnaires’ disease?

A

urinary ag test
x-ray/physical exam to dx pneumonia
expectorated sputum or endotracheal aspirate

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116
Q

what is the most commonly used dx tool in Legionnaires’ disease?

A

urinary ag test

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117
Q

what does the urinary ag test detect for Legionnaires’ disease?

A

serogroup 1 LPS

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118
Q

what serogroup is responsible for 80-90% of community acquired infections of Legionnaires’ disease?

A

serogroup 1

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119
Q

what % of hospital-acquired infections are d/t serogroup 1?

A

<50%

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120
Q

T/F: culture of legionella pneumophilae requires special media

A

TRUE

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121
Q

where is legionella pneumophila found?

A

aqueous environments > warm water

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122
Q

what is the host of legionella pneumophila?

A

free-living amoebas

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123
Q

how do you acquire legionella pneumophila?

A

exposure to contaminated aerosols > air conditioning, cooling towers, hot tubs, misters, etc

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124
Q

T/F: legionnaires disease is common

A

true!

20k-100k cases in US/yr (estimated)

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125
Q

is subclinical infection w/ legionella pneumophila common?

A

YES

indicated by serological testing

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126
Q

why is legionella pneumophila infection often hospital acquired?

A

high # of high-risk pts

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127
Q

how do you prevent & control legionnaires’ disease?

A

routine surveillance for microbial burden

clean & disinfect as appropriate

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128
Q

do you do susceptibility tests for legionnaires’ disease?

A

NOPE

bc it’s too hard to grow the bacterium

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129
Q

why are many abx ineffective against legionnaires’ disease?

A

bc they have poor penetration of macrophages

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130
Q

what abx can you use to treat legionnaires’ disease?

A

macrolides > azithromycin
fluoroquinolones > levofloxacin
tetracyclines > doxy

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131
Q

how do you treat pontiac fever?

A

you don’t

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132
Q

what is the smallest free-living bacterium?

A

mycoplasma

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133
Q

what is unique about mycoplasma’s cell wall?

A

it doesn’t have one

so it is RESISTANT to abx that target the cell wall

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134
Q

what does the cell membrane of mycoplasma contain?

A

sterols from the host

e.g. cholesterol

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135
Q

what does growth in culture of mycoplasma require?

A

medium containing sterols

e.g. animal serum

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136
Q

what is the pathogenesis of mycoplasma?

A

adheres to respiratory epithelium via attachment organelle > destroys cilia then ciliated epithelial cells > irritation & secondary infection

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137
Q

what causes a persistent cough w/ mycoplasma infection?

A

the irritation & secondary infection

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138
Q

what is the primary adhesin for mycoplasma?

A

P1 protein

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139
Q

where are the receptors for mycoplasma?

A

host cells

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140
Q

T/F: most infection w/ mycoplasma is asymptomatic

A

TRUE

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141
Q

what are the 2 clinical diseases assoc w/ mycoplasma?

A

tracheobronchitis

primary atypical pneumonia

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142
Q

what is the most common clinical disease assoc w/ mycoplasma?

A

tracheobronchitis

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143
Q

what are the sx of tracheobronchitis?

A

low-grade fever
malaise
HA
non-productive cough

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144
Q

what is primary atypical pneumonia d/t mycoplasma like for the pt?

A

it’s okay
pts not terribly ill
“walking pneumonia”

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145
Q

what is more impressive than clinical signs in mycoplasma primary atypical pneumonoia?

A

patchy bronchopneumonoia on chest radiograph

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146
Q

how is mycoplasma pneumonia usually diagnosed?

A

empirically, based on clinical signs

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147
Q

can you use microscopy for mycoplasma pneumoniae?

A

NOPE

and it stains poorly too

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148
Q

what does mycoplasma pneumoniae require for growth?

A

special media supplemented w/ serum (sterols)
PLUS it grows really slow (2-6 weeks)
so DON’T CULTURE IT

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149
Q

why don’t you use serology to dx mycoplasma pneumoniae?

A

lacks sensitivity & specificity (both complement fixation & cold agglutinin)

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150
Q

how does cold agglutinin serology work?

A

IgM ab bind to I blood group ag on human RBCs at 4C

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151
Q

how is mycoplasma pneumoniae spread?

A

respiratory droplets

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152
Q

is mycoplasma pneumoniae zoonotic?

A

nope

strictly human

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153
Q

T/F: mycoplasma pneumoniae incidence is seasonal

A

FALSE

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154
Q

all populations are susceptible to mycoplasma pneumoniae, but what age group is primarily infected?

A

children 5-15 yo

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155
Q

what are the 3 best treatments for mycoplasma pneumonia?

A

macrolide (erythro/azithro)
tetracycline (doxy)
fluoroquinolone

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156
Q

which abx can you NOT use for kids that have mycoplasma pneumonia?

A

tetracyclines

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157
Q

which abx is most expensive to treat mycoplasma pneumonia?

A

$$$: fluoroquinolones

$: tetracyclines

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158
Q

what are the 5 types of endemic dimorphic fungi?

A 
histoplasmosis
blastomycosis
coccidiomycosis
paracoccidioidomycosis
penicilliosis
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159
Q

where does histoplasma capsulatum live?

A

soil w/ lots of Nitrogen i.e. bird & bat poop

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160
Q

where is H. capsulatum found in the world?

A

OH & Mississippi river valleys

Mexico, C & S America

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161
Q

what is a major risk factor of H. capsulatum in S & C America & Mexico?

A

AIDS

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162
Q

where is H. capsulatum var. duboisii found in the world?

A

tropical Africa

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163
Q

what are the 4 steps of natural history of H. capsulatum?

A
  1. inhale microconidia
  2. germination into yeast
  3. intracellular growth in lungs
  4. stay local or disseminate
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164
Q

where does h. capsulatum grow in your body?

A

intracellular in the lungs

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165
Q

what is the primary host defense against histoplasmosis?

A

cellular immunity

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166
Q

what type of histoplasmosis is common in endemic areas?

A

acute pulmonary

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167
Q

what are the 4 types of histoplasmosis?

A

acute pulmonary
chronic pulmonary
progressive disseminated
African

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168
Q

what are the sx of acute pulmonary histoplasmosis?

A

usu asymptomatic or flu-like

if sick, fever, HA, non-pdtive cough, chills, chest pain

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169
Q

what are the sx of chronic pulmonary histoplasmosis?

A

fever, pdtive cough, chest pain, CAVITARY LESIONS

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170
Q

what is affected in progressive disseminated histoplasmosis?

A

multiple organ systems

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171
Q

what are the risk factors for progressive disseminated histoplasmosis?

A

55+ yo

immunosuppression

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172
Q

what variant of histoplasma is implicated in African histoplasmosis?

A

h. capsulatum var. duboisii

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173
Q

what are the most commonly involved organ systems in African histoplasmosis?

A

skin & skeleton

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174
Q

what is the histopathology of histoplasmosis?

A

small budding yeasts w/i macrophages

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175
Q

does histoplasma display temp-dependent dimorphism?

A

YEP

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176
Q

what does histoplasma look like at 37 C?

A

yeast

small, oval, budding

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177
Q

what is the mycelium form of histoplasma (what does it look like at 20 C)?

A

tuberculate macroconidia

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178
Q

how does the ag immunoassay for histoplasmosis work?

A

detects cell wall polysaccharide (reference lab only)

179
Q

what is the best sample for the ag immunoassay for histoplasmosis?

A

urine

180
Q

how does serology for histoplasmosis work?

A

tests for serum ab via complement fixation or precipitation

181
Q

what is the false seropositive rate of histoplasmosis in endemic areas?

A

10%

182
Q

what % of pts w/ acute histoplasmosis develop the ab?

A

75%

183
Q

what test has little value for diagnosing histoplasmosis but is useful for epidemiology?

A

skin test

184
Q

what determines delayed hypersensitivity for histoplasmosis?

A

histoplasmin skin test

185
Q

T/F: most cases of acute pulmonary histoplasmosis require no treatment

A

TRUE

186
Q

what does the extent of treatment for histoplasmosis vary with?

A

severity of disease

187
Q

what antifungals can you use for histoplasmosis?

A

itraconazole

amphotericin B or liposomal amphotericin B

188
Q

where does blastomyces dermatitidis live?

A

soil w/ decaying organic matter

189
Q

where is blastomyces dermatitidis found geographically?

A

OH & Mississippi river valleys

SE US

190
Q

what does the endemic area of blastomyces dermatitidis overlap w/?

A

histoplasmosis

191
Q

how does blastomyces dermatitidis get into your body?

A

inhalation of conidia from environmental site

192
Q

what is the natural hx of blastomyces dermatitidis?

A
  1. inhale conidia
  2. germinate into yeast
  3. grow in lungs
  4. remain local or disseminate
193
Q

what animal is highly susceptible to blastomyces dermatitidis infection?

A

dogs

but they are NOT a reservoir

194
Q

what is the primary host defense against blastomycosis?

A

cellular immunity

195
Q

what are the 3 types of blastomycosis?

A

acute pulmonary
disseminated
infection in immunocompromised host

196
Q

what % of cases of acute pulmonary blastomycosis are asymptomatic?

A

50%

197
Q

what is the clinical course of acute pulmonary blastomycosis?

A

asymptomatic but may progress to fulminant respiratory disease w/ abrupt onset of myalgia, arthralgia, chill, fever

198
Q

what is most often involved in disseminated blastomycosis?

A

skin

199
Q

what sites may also be affected in disseminated blastomycosis?

A 
lymph nodes
bones
joints
prostate
CNS
200
Q

what does infection of blastomycosis in an immunocompromised host look like?

A

aggressive! but less common than other fungi

201
Q

what is the histopathology of blastomycosis?

A

broad-based large budding yeasts

202
Q

what does blastomycosis look like at 20C?

A

non-specific mycelium

203
Q

what does blastomycosis look like at 37C?

A

small oval broad-based budding yeasts

204
Q

how do you confirm blastomycosis culture?

A

PCR

205
Q

what 2 tests are USEFUL in diagnosing blastomycosis?

A

culture

ag immunoassay of urine

206
Q

what does the ag immunoassay of urine detect in blastomycosis?

A

detects cell wall polysaccharide (reference lab only) but it’s LOW SPECIFICITY bc it’s cross-reactive w/ other fungi

207
Q

what meds can you use to treat blastomycosis?

A

itraconazole

lipid amp-B

208
Q

what med should you use for mild/moderate blastomycosis?

A

itraconazole

209
Q

what med should you use for severe blastomycosis or blastomycosis in an immunocompromised pt?

A

lipid amp-B

210
Q

what does coccidioides immitis look like in soil?

A

mycelium w/ “barrel shaped” arthroconidia

211
Q

what does coccidioides immitis look like in tissue?

A

endosporulating spherules

212
Q

what does coccidioides immitis live in?

A

soil of dry, low-rainfall areas

213
Q

what is the geographic distribution of coccidioides immitis?

A

SW US (CA, AZ, NM)
Mexico
C & S America

214
Q

there are 2 species of coccidioides. are they distinguishable?

A

nope

215
Q

what species of coccidioides is in California?

A

immitis

216
Q

what species of coccidioides is found in all infectious OUTSIDE of California?

A

posadasii

217
Q

what is the natural history of coccidioides immitis?

A

inhale arthroconidia > germinate in lungs > form spherules > stay local or disseminate

218
Q

what is valley fever?

A

coccidioidomycosis

219
Q

what is the primary host defense against coccidioidomycosis?

A

cellular immunity

220
Q

what are the 3 types of coccidioidomycosis?

A

primary pulmonary
pulmonary nodules & cavities
extrapulmonary dissemination

221
Q

in endemic areas, what % of ppl have primary pulmonary coccidioidomycosis?

A

30-60%

222
Q

how long after exposure do you get symptoms of coccidioidomycosis?

A

7-21 days (1-3 weeks)

223
Q

what are the sx of coccidioidomycosis?

A 
cough
chest pain
SOB
fever
fatigue
224
Q

what % of pulmonary coccidioidomycosis infections get pulmonary nodules & cavities?

A

4%

225
Q

what are the sx of pulmonary nodules & cavities of coccidioidomycosis?

A

pleuritic pain
cough
hemoptysis

226
Q

in 0.5% of the general pop that gets primary coccidioidomycosis infection progresses to what?

A

extrapulmonary dissemination

227
Q

what are the risk factors for extrapulmonary coccidioidomycosis dissemination?

A

immunosuppression

genetics (African or Filipino descent)

228
Q

what is the most serious form of extrapulmonary coccidioidomycosis dissemination?

A

coccidioidal meningitis

229
Q

what establishes diagnosis of coccidioidomycosis?

A

endosporulating spherules in sputum, exudates, or tissue

230
Q

can you culture coccidioides?

A

you can, but it’s less useful than other fungi AND it’s an EXTREME BIOHAZARD!

231
Q

is the mycelium form of coccidioides specific?

A

no

but it does have characteristic arthroconidia (?)

232
Q

what test can be useful in diagnosing coccidioidomycosis in pts w/ non-pdtive cough?

A

serology > tests for serum ab

233
Q

what % of pts w/ acute coccidioidomycosis develop ab?

A

75%

234
Q

what % of normal ppl are positive for coccidioidomycosis in endemic areas?

A

10%

235
Q

what test is useful for epidemiology but not for diagnosis of coccidioidomycosis?

A

coccidioidin skin test

236
Q

what does coccidioidin skin test determine?

A

delayed hypersensitivity

237
Q

what are the treatments for coccidioidomycosis?

A 
oral azole (fluconazole, itraconazole, ketoconazole)
amp-B
238
Q

why is pneumocystis classified as a fungus?

A

rRNA sequences

239
Q

what does pneumocystis lack?

A

ergosterol

240
Q

what species of pneumocystis lives in rats?

A

carinii

241
Q

what species of pneumocystis lives in humans?

A

jirovecii

242
Q

is there an in vitro culture system for pneumocystis?

A

nope

243
Q

T/F: the life cycle of pneumocystis is sexual only

A

FALSE

has sexual & asexual components

244
Q

which microbial forms of pneumocystis are found during human infection?

A

all of them (trophic, sporozoite, & spores)

245
Q

what microbial form of pneumocystis is “free”?

A

trophic

246
Q

what microbial form of pneumocystis is precystic?

A

sporozoite

247
Q

what do pneumocystis cysts contain?

A

up to 8 intracystic bodies

248
Q

what are the 3 microbial forms of pneumocystis?

A

free (trophic)
sporozoite (precystic)
cysts (spores)

249
Q

is natural resistance to pneumocystis high or low?

A

high

250
Q

what happens if a host is compromised and infected w/ pneumocystis?

A

organisms proliferate & gradually fill alveolar lumens

251
Q

what happens in the alveoli w/ pneumocystis infection?

A

foamy exudate in alveolar space
AND
intense interstitial infiltrate of plasma cells

252
Q

what does pneumocystis infection progress to after alveolar infiltration?

A

interstitial fibrosis

edema

253
Q

what classical presentation of pneumocystis occurs in debilitated infants?

A

interstitial plasma cell pneumonitis

254
Q

what sx do immunosuppressed pts get w/ pneumocystis pneumonia?

A

SOB
fever
non-pdtive cough

255
Q

what sx do HIV pts get w/ pneumocystis pneumonia?

A

similar to immunosuppressed presentation but SUBTLE

256
Q

what sx do infants get w/ pneumocystis pneumonia?

A

insidious onset
respiratory distress
cyanosis

257
Q

why is the mortality rate of PCP high if untreated?

A

respiratory failure

258
Q

how do you dx PCP?

A

empirically via clinical signs in an immunosuppressed pt
or
microscopy

259
Q

what is most useful in diagnosing PCP?

A

microscopy

260
Q

what is the sensitivity of BAL fluid staining for PCP?

A

90-100%

261
Q

what forms does the Wright-Giemsa stain work on for PCP?

A

all forms

262
Q

what stain can you use for the cyst form?

A

silver stain

263
Q

what does the cyst form stain look like?

A

(silver stain)

crushed ping pong ball

264
Q

what age does ubiquitous colonization of pneumocystis occur at?

A

early in life, first 2 years

265
Q

how is pneumocystis communicable (what route)?

A

airborne

266
Q

how does immunocompromise allow for pneumocystis infection?

A

reactivation of latent infection
OR
progression of recently acquired infection

267
Q

what are the risk factors for PCP?

A 
malnourished/preemie babies
SCID
hyper-IgM syndrome
immunosuppressive meds
AIDS
268
Q

what has made PCP less frequent in AIDS pts?

A

HAART

269
Q

what is the tx for PCP?

A

TMP-SMZ (prophylaxis AND treatment)

270
Q

who should you use chemophrophylaxis for against PCP?

A

AIDS pts w/ CD4 counts <200/mm3

271
Q

who discovered mycobacteria?

A

Koch

272
Q

what does mycobacteria have in the cell wall?

A

mycolic acid

273
Q

what are mycolic acids?

A

long fatty acids

274
Q

what properties do mycolic acids confer to mycobacteria?

A 
acid-fast
resistant to gram stain
resistant to detergents & hydrophobic abx
survive in macrophages
"cording" arrangement
275
Q

how is the cell wall structure of mycobacteria like a gram+?

A

inner membrane
thick peptidoglycan layer
NO outer membrane

276
Q

how the cell wall structure of mycobacteria NOT like gram+?

A

LAM

additional lipids

277
Q

what is LAM?

A

lipoarabinomannan

functionally similar to O-ag

278
Q

how much of the cell wall weight (%) of mycobacteria is d/t lipids?

A

60%

279
Q

what causes TB?

A

m. tuberculosis complex

280
Q

what are the 5 components of the m. tuberculosis complex?

A

m. tuberculosis
m. bovis
bacille Calmette-Guerin
m. africanum
m. canetti

281
Q

what species cause TB in Africa?

A

m. africanum (duh)

m. canetti

282
Q

what species causes TB in cattle?

A

m. bovis

283
Q

how is m. bovis spread to humans?

A

eating/drinking contaminated dairy products

284
Q

what is bacille calmette-guerin?

A

less virulent strain of m. bovis

285
Q

what is the mycobacteria species that is not part of the m. tuberculosis complex?

A

m. leprae

286
Q

what is another name for atypical mycobacteria?

A

non-TB mycobacteria

287
Q

what is cord factor?

A

trehalose dimycolate
subset of cell wall mycolic acids
glycolipid cell wall component

288
Q

where can you find cord factor?

A

in the cell wall of VIRULENT STRAINS

289
Q

what does cord factor bind to?

A

macrophage surface receptor called MINCLE (minkus!)

290
Q

what does cord factor do once it binds (3 things)?

A

blocks macrophage activation by IFN-gamma
induces secretion of TNF-alpha
causes cord formation

291
Q

is tuberculosis intra or extracellular?

A

INTRACELLULAR

292
Q

what must tuberculosis avoid being killed by?

A

macrophages

293
Q

what are the 2 types of TB?

A

primary

reactivated

294
Q

how does reactivation TB happen?

A

waning/loss of cellular immunity allows for bacterial outgrowth

295
Q

what is the response to reactivation TB?

A

destructive delayed-type hypersensitivity

296
Q

in primary TB, what phagocytizes the bacteria?

A

alveolar macrophages

297
Q

how does primary TB survive in the body?

A

prevents fusion of phagosome w/ lysosome (in macrophage)

298
Q

what happens to infected macrophages in primary TB?

A

secrete cytokines (IL-12 & TNF-alpha)

299
Q

what do the cytokines from primary TB-infected macrophages drive?

A

drive T cells to differentiate into Th1 cells that secrete IFN-gamma

300
Q

in primary TB, what does IFN-gamma do?

A

activates infected macrophages

promotes phagosome-lysosome fusion & killing via ROS & RNS

301
Q

in primary TB, what can the delayed-type hypersensitivity response lead to?

A

granuloma

302
Q

what is a primary TB granuloma composed of (5 things)?

A 
lymphocytes
macrophages
epithelioid cells
fibroblasts
giant cells
303
Q

how is primary TB resolved?

A

either the bacteria go dormant or you have to kill them

304
Q

what are the sx of primary TB?

A

usu asymptomatic

OR can be mild fever & malaise

305
Q

what can you see on radiographs of primary TB?

A

mid-lung infiltrates

hilar lymphadenopathy

306
Q

what 2 things can primary TB progress to?

A

reactivation

dissemination

307
Q

what % of pts w/ primary TB reactivate?

A

10%

308
Q

what pt population gets reactivation TB?

A

men 50+yo

309
Q

what disease is reactivation TB most often assoc w/?

A

immunosuppression

AIDS is most common

310
Q

what are the sx of reactivation TB?

A 
dry cough that becomes productive & mixed w/ blood (hemoptysis)
fever
malaise
sweating
weight loss
311
Q

what do the lungs look like in reactivation TB?

A

cavities in apices (it rhymes!)

cavities have TONS of bacteria

312
Q

what happens if you don’t treat reactivation TB?

A

death in 2-5 years

313
Q

what disorders can lead to a more rapid course of reactivation TB?

A

AIDS

other T cell compromise

314
Q

make sure you look at SLIDE 69 > extrapulmonary TB bc idk how to make a card about it

A

okie dokie

315
Q

what allows for a presumptive dx of TB?

A

radiology

316
Q

why is radiology important w/ TB?

A

central to dx
asses extent & character of disease
evaluate response to tx

317
Q

on radiology, what is highly suggestive of TB?

A

patchy or nodular infiltrate in the lung apices, esp if the infiltrate is cavitary

318
Q

what are the 2 things you can do to immunodiagnose TB?

A

skin test

IFN-gamma-release assay

319
Q

what can you do on microscopy to dx TB?

A

acid-fast stain

320
Q

when you do a TB skin test, what do you inject & where do you inject it?

A

INTRADERMAL injection of 5 tuberculin units of PPD

321
Q

what is PPD?

A

purified protein derivative

cell wall protein

322
Q

how long after the injection should you look at the skin site?

A

48-72 hours

323
Q

what are you looking for w/ a TB skin test?

A

INDURATION

NOT ERYTHEMA!

324
Q

what are the 3 cutoffs in size of the TB skin test reaction?

A

5 mm cutoff for immunosuppressed or recent contacts
10 mm cutoff for other high risk groups
15 mm cutoff for low risk groups

325
Q

what does a positive TB skin test imply?

A 
INFECTION
NOT DISEASE (necessarily)!!!
326
Q

what can cause a false positive TB skin test?

A

infection w/ non-mycobacterium TB mycobacteria (non-Mtb)

327
Q

what can cause a false negative TB skin test?

A

generalized illness or immunosuppression

328
Q

what are not necessarily recommended for negative skin TB tests, even though they can identify anergy?

A

additional skin tests w/ candida or mumps ag

329
Q

how can you identify cell mediated immunity to TB (what test)?

A

IFN-gamma release assay

330
Q

how do you do the IFN-gamma release assay?

A

incubate whole blood w/ Mtb ag

measure the release of IFN-gamma

331
Q

what are the antigens in the IFN-gamma release assay (generally)?

A

3 Mtb proteins NOT FOUND in NON-Mtb species

332
Q

what are the 3 advantages to the IFN-gamma release assay?

A

no rxn in ppl who received BCG
no need to return to have skin test eval
no booster effect w/ repeat testing

333
Q

what are the 2 disadvantages to the IFN-gamma release assay?

A

$$$$$

lab infrastructure

334
Q

what is now recommended by the CDC to detect Mt infection & surveillance?

A

IFN-gamma release assay

335
Q

what do you do with a smear of a suspected TB sample?

A 
cover w/ stain
heat it up
rinse
decolorize w/ acid alcohol
counterstain w/ methylene blue
336
Q

what conc is required for Mtb positivity on a slide?

A

10,000 Mtb/mL is positive
>/= 10 Mtb on a slide = optimal
a single organism is highly suggestive

337
Q

what dyes are the most sensitive for Mtb?

A

fluorescent

338
Q

what should you use in resource limited countries to dx TB?

A

LED microscopes

339
Q

what stain is hot acid fast?

A

Ziehl-Nielsen (cause Zayn is the hottest dude in one direction)

340
Q

what stain is cold acid fast?

A

Kinyoun (Kin cold)

341
Q

what stain is fluorochrome acid fast?

A

Truant (T & F both have crosses)

342
Q

how do nucleic acid-based tests for TB work?

A

PCR amplification of a clinical sample

343
Q

what is the sensitivity of nucleic-acid based tests (compared to other diagnostic tools, not a number)?

A

intermediate btwn acid fast & culture

344
Q

what are the 2 advantages to the nucleic acid-based tests for TB?

A

simultaneously assess resistance to RIFAMPIN (surrogate for MDR)
AND
can be self-contained (Cephid) > advantage for resource-limited countries

345
Q

what are the 3 disadvantages of nucleic acid-based tests for TB?

A

sensitivity & ease of use varies
some tests require advanced lab infrastructure
too $$$ for resource-limited

346
Q

what is the GOLD STANDARD for TB dx?

A

CULTURE!

347
Q

what can culture of TB detect (concentration)?

A

10-100 Mtb/mL (which is a lower conc than acid fast so it’s BETTER than acid fast)

348
Q

what do samples from contaminated sites require?

A

decontamination

349
Q

can mycobacteria survive decontamination?

A

yes

mild decontamination

350
Q

what are the 2 culture media for TB?

A

solid
AND
liquid

351
Q

what are the 2 types of solid culture media for TB?

A

Lowenstein-Jensen

Middlebrook

352
Q

how long does TB culture on solid medium take?

A

3-8 weeks

353
Q

how long does TB culture on liquid medium take?

A

1-3 weeks

354
Q

how can you identify TB cultures?

A

colony morphology
biochemical tests
species-specific molecular probes

355
Q

what are the 3 ways to detect abx sensitivity of TB?

A

agar proportion
liquid broth systems
molecular tests

356
Q

how does the agar proportion for TB abx sensitivity work?

A

determines percentage of resistant Mtb

357
Q

why are the liquid broth systems for TB abx sensitivity good?

A

provide FASTER results

358
Q

what do the molecular tests for TB abx sensitivity detect?

A

resistance to RIFAMPIN

359
Q

what % of the world’s population is infected w/ TB?

A

33% (1/3)

360
Q

how many new cases & deaths does TB cause annually?

A

9 million new cases

2 million deaths

361
Q

how many new cases of TB are there in the US per year?

A

11,000

362
Q

most cases of TB in the US are what kind of TB?

A

reactivation

most are foreign-born

363
Q

how is TB spread?

A

person-to-person (humans ONLY) via airborne droplets

364
Q

how are most TB infections dealt with in the body (very generally)?

A

immune system

365
Q

who is at risk of exposure to TB via close contact?

A

healthcare workers

“institutional exposure”

366
Q

exposure to TB depends on what 2 things?

A

closeness of contact

infectiousness of source (i.e. cavitary TB)

367
Q

what is the biggest risk factor for TB?

A

immunosuppression

368
Q

what are the 4 first line drugs used in combo for TB treatment?

A 
isoniazid
rifampin
ethambutol
pyrazinamide
(IREP)
369
Q

how does isoniazid work?

A

inhibits synthesis of mycolic acid

370
Q

how does rifampin work?

A

inhibits DNA-dependent RNA polymerase

371
Q

how does ethambutol work?

A

inhibits cell wall synthesis

372
Q

how does pyrazinamide work?

A

who knows

“mechanism not well understood”

373
Q

what “other agents” does Kozel list that you can also use to treat TB?

A

aminoglycosides

fluoroquinolones

374
Q

how do you combat the emergence of abx resistance in TB?

A

use 4 drugs

375
Q

what are the 2 other treatment things you can do for TB?

A

directly-observed treatment

consulting current guidelines

376
Q

what is MDR TB resistant to?

A

at least

isoniazid AND rifampin

377
Q

in what population was MDR TB first observed?

A

in AIDS & homeless people in NYC & Miami

378
Q

what causes MDR TB?

A

interrupted abx course

drug levels insufficient to kill 100% of bacteria

379
Q

what is XDR TB?

A

EXTENSIVELY drug resistant TB

380
Q

how does XDR TB start?

A

as MDR TB

381
Q

what is XDR TB resistant to?

A 
isoniazid
rifampin
quinolones
AND
at least 1 second-line drug
382
Q

where can you find XDR TB?

A

most regions of the world

383
Q

can you treat XDR TB?

A

maybe?

“potentially untreatable”

384
Q

what is the BCG vaccine?

A

LIVE vaccine of Bacille Calmette-Guerin (less virulent strain of M. bovis)

385
Q

how many people got BCG vaccine?

A

3-5 BILLION

more than any other vaccine

386
Q

who gets the BCG vax?

A

infants in endemic countries

NOT in the US or other countries w/ low incidence of TB

387
Q

what positive effect has the BCG vax had?

A

reduced incidence of disseminated TB in kids

388
Q

what does the BCG vax do with the TB skin test?

A

produces false-positive

but skin test reactivity is low

389
Q

what does BCG NOT consistently reduce?

A

incidence of adult pulmonary disease

390
Q

what can happen if you give the BCG vax to pts w/ primary or acquired immune deficiency (AIDS)?

A

BCG disease

but not autism!

391
Q

are non-TB mycobacteria (NTM) & atypical mycobacteria the same thing?

A

yup

392
Q

how do you classify NTM?

A

growth rate

pigmentation (Runyon)

393
Q

what are the 5 major disease producing species of NTM?

A 
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
Q

how do you get NTM?

A

environmental sources i.e. tap water

395
Q

how many species TOTAL are there of NTM that cause disease?

A

> 50

396
Q

what diseases/syndromes can result from NTM?

A
  1. chronic bronchopulmonary disease
  2. skin & soft tissue disease
  3. lymphadenitis
  4. disseminated disease in immunosuppressed pts (AIDS)
397
Q

how do you dx NTM?

A

same as Mtb

398
Q

how do you treat NTM?

A

it depends on the species

“tx varies dramatically w/ various NTM species”

399
Q

which NTM has a high degree of abx resistance?

A

m. abscessum

400
Q

what are the abx resistance mechanisms of m. abscessum?

A

abx modifying enzymes
abx degrading enzymes
target modification
efflux pumps

401
Q

what abx is m. abscessum resistant to via abx modifying enzymes?

A

aminoglycosides

402
Q

what abx is m. abscessum resistant to via abx degrading enzymes?

A

beta lactams

403
Q

what abx is m. abscessum resistant to via target modification?

A

macrolides

404
Q

how do you treat m. abscessum?

A

long-term abx

surgical intervention to drain any lesions

405
Q

what case study is assoc w/ m. abscessum?

A

medical tourism for cosmetic surgery in the dominican republic

406
Q

what are the 2 species in the mycobacterium avium complex (MAC)?

A

m. avium
m. intracellulare
(birds INSIDE a birdcage)

407
Q

what are the 4 diseases assoc w/ MAC?

A
  1. primary infection
  2. chronic localized pulmonary disease
  3. disseminated disease in advanced AIDS
  4. cervical lymphadenitis
408
Q

can you get reactivation disease w/ MAC?

A

NOPE

409
Q

what kinds of pts get chronic localized pulmonary disease d/t MAC?

A

pts have intact immunity
smokers
COPD pts

410
Q

which AIDS pts get disseminated disease?

A

the ones w/ CD4 <100/mm3

it was very common prior to HAART

411
Q

is microscopy for MAC good?

A

nope

lacks sensitivity & specificity

412
Q

can you culture MAC?

A

yep

PLUS blood culture for disseminated disease

413
Q

how do you get MAC?

A

from the environment via inhalation or ingestion

414
Q

T/F: MAC spreads via person-to-person transmission

A

FALSE

none of that

415
Q

what environmental sources can harbor MAC?

A

natural water sources
indoor water systems
pools
hot tubs (great)

416
Q

T/F: treating MAC is easy peasy lemon squeezy

A

FALSE
very difficult!
high treatment failure rate!

417
Q

what abx can you use for MAC?

A 
clarithromycin or azithro
PLUS
ethambutol
PLUS
rifabutin
(C you in the ER cause you got MAC)
418
Q

what should you do for pts if they have a CD4 <50 cells/mm2?

A

azithromycin prophylaxis for MAC

419
Q

T/F: Nocardia is WEAKLY acid fast

A

TRUE

420
Q

what shape is Nocardia?

A

filamentous rods

421
Q

what species of Nocardia should you be worried about?

A

Nocardia asteroides complex (asteroides, brasiliensis)
Rhodococcus
Gordonia
Tsukamurella

422
Q

which Nocardia species are RARE and implicated in opportunistic infections?

A

Gordonia

Tsukamurella

423
Q

which species of Nocardia is uncommon and involved in pulmonary, cutaneous, and CNS disease?

A

Rhodococcus

424
Q

what is the virulence of nocardia related to?

A

ability to avoid intracellular killing

425
Q

what inactivates the toxic metabolites of nocardia?

A

catalase

superoxide dismutase

426
Q

what does cord factor do in nocardia?

A

prevents intracellular killing

prevents phagosome-lysosome fusion

427
Q

what 2 disease classes can Nocardia cause?

A

bronchopulmonary

cutaneous

428
Q

who gets bronchopulmonary nocardia disease?

A

immunocompromised pts

429
Q

what is the course of bronchopulmonary nocardia infection?

A

disseminates to the CNS or skin

430
Q

what is a mycetoma?

A

cutaneous Nocardia infection involving chronic granulomatous destruction of extremities

431
Q

how can cutaneous nocardia manifest?

A

mycetoma
lymphocutaneous infection
cellulitis
subQ abscess

432
Q

what does nocardia in sputum look like?

A

beaded filaments!

433
Q

how do you distinguish Nocardia from actinomyces?

A

ACID-FAST STAIN!

Nocardia is weakly acid fast

434
Q

how do you culture Nocardia?

A

special media

notify lab

435
Q

what does nocardia look like on agar culture?

A

aerial hyphae (looks like cotton)

436
Q

when you do a molecular analysis of nocardia, what are you doing?

A

sequencing the rRNA

437
Q

where is nocardia ubiquitous?

A

soil that has organic matter

438
Q

how do you get nocardiosis?

A

inoculation of skin or inhallation

439
Q

who gets nocardiosis?

A

mostly immunocompromised pts

440
Q

what is the primary abx for nocardiosis?

A

TMP-SMX

441
Q

how do you treat nocardiosis in an immunocompromised pt?

A

TMP-SMX
PLUS
amikacin OR imipenem OR broad-spectrum cephalosporin

442
Q

how long do you treat nocardiosis for?

A

12 months!

443
Q

how can you treat a really extensive nocardia infection?

A

surgical mgmt

444
Q

FUCK YEAH YOU JUST WENT THROUGH 443 CARDS ABOUT FUCKING STUPID ASS BACTERIA!

A

YOU DID IT! YOU’RE AMAZING!

Block 9 Week 3 (8 decks)

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