L10 - Lower Respiratory Tract Infections

Question 1

Is the LRT sterile?

Answer 1

YES

Question 2

How is the LRT sterile?

Answer 2

Mucociliary escalator

Phagocytosis

Question 3

What is the virulence of LRT pathogens partly dependent on?

Answer 3

ability to evade phagocytosis

Question 4

What are the 3 ways infectious agent gain entry into LRT by?

Answer 4

Inhalation of aerosolised material

aspriation of URT commensals - lose gag reflex when drunk

hametogenous spread

Question 5

what are the 3 types of pneumonia?

Answer 5

community-acquired pneumonia

hospital-acquired pneumonia

ventilator-associated pneumonia

Question 6

What is community acquired pneumonia?

Answer 6

2 subtypes

• acute lobar pneumonia
• aytpical penumonia

Question 7

What is hospital-acquired pneumonia?

Answer 7

pneumonia when patients are hospitalised for more than 72h

Question 8

What is ventilator-associated pneumonia?

Answer 8

mechaniclly ventilated for more than 48 h

Question 9

What bacteria infections lead to CA pneumonia in NEONATES?

Answer 9

Group B strep

L. monocytogenes

Question 10

What bacteria infections lead to CA pneumonia in infants?

Answer 10

Encapsulated bacteria

C. trachomatis (abuse)

Question 11

What bacteria infection lead to CA pneumonia in children/young adults?

Answer 11

S. pneumoniae
M. pneumoniae
C. pneumoniae

Question 12

What bacteria infections lead to CA pneumonia in older adults?

Answer 12

S. pneumoniae

Legionella spp. (sick building syndrome)

Question 13

What bacteria cause HA pneumonia?

Answer 13

P.aeurginosa

Gram-neg bacilli, MRSA

Question 14

What bacteria cause HA pneumonia in CF patients?

Answer 14

P. aeruginosa

Burkholderia cepacia complex

S. aureus ( unusual nasty version )

Question 15

What bacteria cause HA pneumonia in AIDS patients?

Answer 15

Pneumocystis Jiroveci

Question 16

What is lobar pneumonia ALMOST always caused by?

Answer 16

S. pneumoniae

Question 17

What are features of S. pneumoniae?

Answer 17

Gram-pos coccus

fastidious

a-haemolysis on FBA

Question 18

What is the main cause of Bronchopneumonia?

Answer 18

S. aureus

Question 19

What is bronchopneumonia?

Answer 19

secondary infection

‘plums and custard’ sputum

Question 20

What are other causes of bronchopneumonia?

Answer 20

K. pneumoniae
Coliforms
P. aeruginosa

Question 21

What is necrotising pneumonia caused by?

Answer 21

S.aureus elaborating Panton-Valentine Leukocidin

Question 22

What does Panton-Valentine leukocidin do?

Answer 22

beta-barrel toxin

inserts in membrane, produces holes in membrane

Question 23

What is Legionnaire’s disease?

Answer 23

Legionellla pneumonia - poor staining gram-neg

symptoms resemble flu

can progress systemic

Question 24

Where does legionella thrive?

Answer 24

lakes
rivers
ponds

WARM STAGNANT WATER

Question 25

What is atypical pneumonia also called?

Answer 25

walking pneumonia non-cultivable pneumonia

Question 26

What is used to treat atypical pneumonia?

Answer 26

Erythromycin

Question 27

How is pneumonia diagnosed CLINICALLY?

Answer 27

CURB65 score of severity in CAP ^ score above 3 get admitted to hospital X-ray Ultrasound (make sure it's not empyema)

Question 28

What do pneumonia diagnosis CLINICAL results inform on?

Answer 28

EMPIRICAL THERAPY

Question 29

How is pneumonia diagnosed in the lab?

Answer 29

sputum broncho-alveolar lavage blood culture urine NAAT immunoassay

Question 30

What do results from lab diagnosis inform on?

Answer 30

DIRECTED THERAPY

Question 31

What classes as a good sputum?

Answer 31

lack of squames one organism dominates

Question 32

What us chronic bronchitis?

Answer 32

overproduction of mucus typically H. influenzae secondary bacterial infections complicate reovery

Question 33

What causes Whooping cough?

Answer 33

Bordetella pertussis

Question 34

What are the 2 toxins associated with Bordetella pertussis?

Answer 34

Pertussis toxin (PT) Adenylate cyclase toxin (AC)

Question 35

symptoms of whooping cough?

Answer 35

adheres to trachea interferes with mucociliary escalator paroxysmal coughing high-pitched inspiration

Question 36

How does PT toxin act?

Answer 36

BINARY (AB) A-subunit binds G proteins stops cyclicAMP production blocks recruitment of immune cells

Question 37

How does AC toxin act?

Answer 37

BIFUNCTIONAL Ac domain - produce greater amounts of cAMP = immune evasion RTX domain - pore within host cell = leakage

Question 38

What is respiratory Tb caused by?

Answer 38

M. tuberculosis M. bovis M. MAC (immunocompromised) M. kansasii

Question 39

Where does Tb cause disease?

Answer 39

upper lobes | obligate aerobes

Question 40

Symptoms of Tb?

Answer 40

night sweats fever weight loss

Question 41

How does the immune system restrict spread of Tb?

Answer 41

granuloma

Question 42

How is Tb diagnosed in the lab?

Answer 42

observe in sputum/BAL culture MGIT - see fluorescence when oxygen gets scavenged NAAT - sensitivity issues IFN-y release assay - doesn't distinguish latent from active