Intro to Resp Infx Disease

Question 1

3 mechanisms of disease for bacteria:

Answer 1

1. Toxin production
2. Host immune response
3. Bacterial proliferation and invasion

Question 2

3 mechanisms of disease for viruses:

Answer 2

1. Cytopathic effect–> cell death and disease
2. Host immune response

3 . Tumorigenesis

Question 3

Two main obstacles microorganisms must overcome to infect upper resp tract:

Answer 3

1. mucous

2. phagocytosis (avoid it or be able to survive it)

Question 4

Two basic components of the mucociliary elevator:

Answer 4

1. goblet cells–produce mucus

2. ciliated epithelium

Question 5

Most common pathogen causing common cold?

Answer 5

rhinovirus

Question 6

Pathogen causing common cold any time of year?

Answer 6

adenovirus

Question 7

Pathogenesis of rhinovirus; adhesion and sx cause?

Answer 7

ICAM-1 (adhesion)

lytic infx destroying ciliated epithelial cells

Question 8

If clear discharge from common cold becomes purulent think?

Answer 8

secondary bacterial infx

Question 9

RNA

Icosahedral capsid

NON-enveloped

SS(+) non-segmented (class IV)

Picoraviridae

Answer 9

Rhinovirus

Question 10

RNA

Helical capsid

Enveloped

SS(-) non-segmented (class V)

Paramixoviridae

Answer 10

Parainfluenza virus

Paramyxovirus

Question 11

RNA

Helical

Enveloped

SS(+) non-segmented (class IV)

Answer 11

Coronaviridae

Coronavirus

Question 12

RNA

Helical

Enveloped

SS(-) Non-segmented (class V)

Orthomyxoviridae

Answer 12

Influenza A, B, C

Question 13

RNA

Icosahedral

Non-enveloped

SS(+) Non-segmented (class IV)

Picornaviridae

Enterovirus

Answer 13

Coxsackie A and B

Question 14

DNA

Icosahedral

Non-enveloped

DS linear DNA (group I)

Answer 14

Adenoviridae

Adenovirus (Mastadenovirus)

Question 15

Most common viral cause of conjunctivitis:

Answer 15

adenovirus

Question 16

inflammation or infx of nasal mucosa + at least one paranasal sinus lasting

Answer 16

acute rhinosinusitis

Question 17

Two most common bacterial causes of community acquired acute bacterial rhinosinusitis:

Answer 17

S. pneumo

H. influenzae

Question 18

Refractory sinusitis may be?

Answer 18

Aspergillus fumigatus

Question 19

Treatment of fungal sinusitis in immunocompetent:

Answer 19

mechanical removal

Question 20

Patients at higher risk in fungal sinusitis:

Answer 20

immune compromised

Question 21

General differentiating factors in viral vs bacterial sinusitis:

Answer 21

duration (> 7 days adult, >10-14 days children)

severity of sx (ie. facial pain, fever > 102)

Question 22

Evidence based treatment of viral sinusitis sx:

Answer 22

saline wash

Question 23

Abx for bacterial sinusitis:

Answer 23

First line: amoxicillin

second: azithromycin

Question 24

Gram +

diplococci

Catalase -

a-hemolytic

Bile-Esculin Negative

Optochin susceptible

+ Quellung

Answer 24

S. pneumoniae

Question 25

Gram - Cocobacilli, Pleomorphic X and V factors required + Quellung

Answer 25

H. influenzae

Question 26

Most common cause of pharyngitis:

Answer 26

viral

Question 27

most common bacterial cause of pharyngitis:

Answer 27

S. pyogenes

Question 28

pharyngitis military or boarding school

Answer 28

adenovirus

Question 29

viral pharyngitis in adolescents in winter

Answer 29

EBV

Question 30

Pharyngitis + conjunctivitis strongly suggests:

Answer 30

viral cause

Question 31

Pharyngitis + fever + severe pain w/swallowing suggests:

Answer 31

S. pyogenes

Question 32

S. pyogenes attachment VF's:

Answer 32

M protein lipoteichoic acid protein F

Question 33

S. pyogenes prevents phagocytosis via (VFs):

Answer 33

hyaluronic acid CAPSULE

Question 34

S. pyogenes invasion VFs:

Answer 34

protease hyaluronidase

Question 35

S. pyogenes (shape?) catalase (?) ? hemolytic bacitracin (?)

Answer 35

cocci catalase - Beta - hemolytic bacitracin SENSITIVE

Question 36

C. diptheriae Gram (?) (shape?) spore forming (?) motility (?)

Answer 36

Gram + bacilli NON-spore forming NON-motile

Question 37

Tx for S. pyogenes pharyngitis?

Answer 37

penicillin | erythromycin, 2nd line if penicillin allergy

Question 38

Scarlet Fever causing exotoxins of S. pyogenes:

Answer 38

speA speC ssa ***superantigens

Question 39

"Strawberry tongue"

Answer 39

Scarlet Fever (S. pyogenes)

Question 40

What does catalase do? Does S. pyogenes have it?

Answer 40

converts H2O2 --> H2O + O2 (bubbles formes) nope

Question 41

How do aerobes deal with reactive oxygen species?

Answer 41

superoxide dismutase

Question 42

"bark-like" cough

Answer 42

croup

Question 43

Causes croup any time of year:

Answer 43

Parainfluenza virus

Question 44

Cause croup mostly in winter and early spring:

Answer 44

Influenza virus Respiratory syncytial virus

Question 45

RNA Helical capsid Enveloped SS(-) non-segmented (class V) Paramixoviridae Pneumovirus

Answer 45

Respiratory Syncytial Virus (RSV)

Question 46

What are the two paramyxoviruses that cause croup? What is the VF involved? What does that VF do?

Answer 46

RSV Parainfluenza virus F-protein Fusion of respiratory epithelial cells--> multinucleated cells

Question 47

Most frequent cause of epiglotitis?

Answer 47

group A strep beta hemolytic (ie. S. pyogenes) #2 H. influenzae (actually the only one mentioned in FA), now less common d/t vaccination So hopefully the Q stem includes gram stain

Question 48

Tx for epiglotitis:

Answer 48

SECURE AIRWAY ``` 2nd or 3rd gen Cephalosporin + penicillinase resistant penicillin: Claxacillin, Oxacillin, Naficillin, Dicloxacillin, Methicillin ```

Question 49

Differentiates epiglotitis from croup:

Answer 49

Onset (sudden vs gradual) Supraglottic vs subglottic High fever vs low fever Severe dysphagia vs mild or absent Drooling vs none Uncommon cough vs barking cough Positive thumb sign vs steeple sign on imaging

Question 50

multinucleated giant cells associated with?

Answer 50

Parainfluenza virus

Question 51

VF for Parainfluenza virus adhesion to sialic acid?

Answer 51

hemagglutinin (HA)

Question 52

VF for Parainfluenza virus cleaving hemagglutinin facilitating viral spread:

Answer 52

neurominidase (NA)

Question 53

vesicles on hands, feet, and mouth typically young children

Answer 53

Coxackievirus A and B "hand, foot and mouth disease"

Question 54

gray fibrinous exudate

Answer 54

C. diphtheriae

Question 55

"Chinese letters" under microscope

Answer 55

C. diphtheriae

Question 56

Strep. pneumoiae is ___hemolytic.

Answer 56

alpha

Question 57

Strep pneumo is Bile-Esculin + or - ?

Answer 57

- negative

Question 58

Is Strep pneumo optochin susceptable?

Answer 58

yes

Question 59

S. pneumo: Quellung + or - ?

Answer 59

+ positive

Question 60

Essential VF for S. pneumoniae

Answer 60

capsule **also has IgA protease -- this makes sense because it's going to see a lot of IgA

Question 61

S. pneumo Optochin ?

Answer 61

SENSITIVE

Question 62

S. pneumo Quellung?

Answer 62

POSITIVE +++++++++++++++

Question 63

H. influenzae Quellung ?

Answer 63

POSITIVE +++++++++++++++

Question 64

S. pyogenes bacitracin ?

Answer 64

sensitive

Question 65

What does C. diphtheriae look like on gram stain?

Answer 65

purple rod Gram + bacilli

Question 66

E. coli catalase ?

Answer 66

positive