L15- RTI V

Question 1

Acute Bronchitis:

• (1) definition
• (2) defining Sxs
• (3) is the most common cause, (4) is second most
• (5) is the way to distinguish from pneumonia

Answer 1

1- inflammation of bronchi due to upper airway infection
2- cough > 5 days lasting 1-3 weeks
3- viruses
4- bacteria
5- pneumonia has systemic symptoms like fever

Question 2

Croup = (1):

• (2) typical age of infection
• (3) list the characteristic Sxs
• (4) is the most common cause, (5) are other frequent causes
• (6) is a common complication

Answer 2

1- laryngotracheitis, laryngotracheobronchitis (inflammation of larynx, sub-glottic area)
2- 6 mos - 3 yrs
3- inspiratory stridor, ‘barking cough’ in children (hoarseness in older people)
4- HPIV-1
5- RSV, adenovirus
6- secondary bacterial infections

Question 3

Croup:

• (1) are the initial typical Sxs
• (2) is a key associated Sx
• (3) is the most severe complication
• (4) is the radiological feature

Answer 3

1- non-specific URI sxs
2- mild fever, <40C
3- severe respiratory distress
4- subglottic narrowing of trachea = ‘steeple sign’

Question 4

list the important Paramyoxviridae by subfamiles

Answer 4

1) paramyxovirinae: HPIV-1/3 (respirovirus), HPIV-2/4 (rubulavirus)
2) pneumovirinae: RSV

Question 5

Paramyxoviridae:

• (non-/enveloped) (+/-) sense (ss/ds)(DNA/RNA) with (5) nucleocapsid shape
• replication occurs in (cytoplasm/nucleus)
• transmitted via (7)

Answer 5

(HPIV, RSV)
1-5- enveloped (-) sense ssRNA, helical nucleoocapsid
6- cytoplasmic replication
7- respiratory droplets

Question 6

List the important VAPs seen in paramyxoviruses, include function

Answer 6

F, fusion protein: forms syncytia between cells, allows for travel/spread from cell to cell (HPIV and RSV)

• HN, hemagglutinin-neuramidase (HPIV only): H for attachement, N for lysis/release
• G, glycoprotein (RSV only): attachment and cell entry

Question 7

HPIV infections, list the predisposing factors (hint- 2 main ones, 3 other ones)

Answer 7

• vitA deficiency
• lack of breast feeding
• malnutrition
• overcrowding
• environmental smoke (infantile exposure) or toxins

Question 8

HPIV infections:

• (1) is form of transmission
• requires a (large/small) inoculating dose
• (3) incubation period

Answer 8

1- respiratory droplets or direct contact with secretions / fomites
2- small dose needed
3- 1-7 days

Question 9

Croup is mainly caused by…..

Answer 9

(laryngotracheitis)

HPIV-1, 2, 3

Question 10

list the membrane proteins for HPIV, include function (include shape)

Answer 10

(spherical shape)
1) F, fusion protein: forms syncytia between cells

2) HN, hemagglutinin-neuramidase: H for attachement, N for lysis/release

3) M, matrix protein: assembly
4) P, phosphoprotein: along with F, induces cell-mediated immune response
5) N, nucleoprotein
6) L, RNA dep. RNA polymerase

Question 11

HPIC, name the viral protein:

• (1) syncytium formation
• (2) immune evasion
• (3) attachment, entry, and release of virus
• (4) matrix structural protein, assembly
• (5) polymerase

Answer 11

1- F, fusion proteins
2- P/F proteins (disrupts IFN production)
3- HN protein
4- M, matrix protein
5- L protein

Question 12

describe how P/F proteins on HPIV work to evade immune response

Answer 12

blocks IFN-α/β production and signaling pathways

Question 13

Bronchiolitis:

• (1) definition
• (2) most affected age group
• (3) season with highest incidence
• (4) Sxs followed by (5)

Answer 13

1- inflammation of bronchioles and small bronchi
2- <2y/o
3- fall, winter
4- URI sxs
5- LRT infection w/ inflammation

Question 14

Bronchiolitis:

• (1) most common cause
• (2) other causes
• (3) list the numerous risk factors

Answer 14

1- RSV (respiratory syncytial virus)
2- rhinovirus, HPIV, adenovirus, coronavirus

3- prematurity (<35 wks), low birth weight (<2.5 kg), congenital/cyanotic heart disease, chronic pulmonary disease, passive smoking, overcrowding, daycare

Question 15

In bronchiolitis, (1) will infect (2) cells causing direct (3). (4) will accumulate as a result of (3), and can lead to (5) complication.

Answer 15

1- virus (causal agent)
2- terminal bronchiolar epithelium
3- cell damage and inflammation
4- edema, excess mucus, sloughed epithelial cells
5- small airway obstruction and atelectasis

Question 16

Bronchiolitis:

• starts with (1) type Sxs
• (2) sxs start next, include specifics
• illness duration depends on (3)
• (4) is the end result of most infections

Answer 16

1- URI sxs (nasal congestion and discharge)
2- LRT infections sxs: fever <101F, cough, respiratory distress (inc RR, retractions, wheezing, crackles), preceding h/o URI
3- age, severity, associated conditions, causative agent
4- self-limiting

Question 17

(1) is the leading cause of LRTIs in infants/young children, mainly causing (2) and (3). Infections by (1) are usually limited by (4). (1) LRTIs are also linked to (5) in infancy, although association remains controversial.

Answer 17

1- RSV
2- bronchiolitis
3- viral pneumonia
4- to respiratory tract
5- subsequent reactive airway disease

Question 18

list the risk factors for RSV infections

Answer 18

• infants < 6 mos
• immuno-compromised
• asthma

Infants with: *Down syndrome, underlying lung disease, premature birth (<35 wks), congenital heart disease, passive smoking

Question 19

RSV:

• (1) family, subfamily, genus
• (non-/enveloped), (3) capsid shape
• list important VAPs, (4)

Answer 19

1- paramyxoviridiae, pneumovirinae, pneumovirus
2- enveloped, helical nucleocapsid (neg. sense ssRNA, cytoplasm replication)
3:
-F, fusion factor: main viral Ag, forms syncytia between cells
-G glycoprotein: attachment
(NOTE- no HN glycoprotein)

Question 20

RSV enters body via (1) process. (2) are responsible for attachment and fusion to target cells. (3) is the primary site of replication and has a (4) direct effect on (3). It will spread to (5) after (6) days via various mechanism.

Answer 20

1- large droplets on hands –> self inoculation to epithelia of nose, eye
2- F/fusion protein, G glycoprotein
3- nasopharyngeal epithelium
4- cytopathic effect => loss of function for (3)
5- LRT
6- 2-5 days

Question 21

It is suggested that ____ is responsible for the immune response to RSV.

Answer 21

Tc cells (CD8+)

Question 22

It is thought that (1), (2), (3) are directly responsible for the clinical outcome of RSV infections..

Answer 22

1- immunological response

2- anatomy of airway (worse in younger people with already narrow airways)

3- tropism for respiratory epithelium

Question 23

Whooping cough is caused by (1), and is also called (2) cough. It typically occurs in (3) people, where (4) are the normal reservoirs.

Answer 23

1- bordetella pertussis
2- 100 day cough
3- unvaccinated children <10y/o
4- adults
(Note- highly communicable)

Question 24

Bordetella pertussis: (large/small) (thin/thick) Gram(+/-) (cocci/bacillus)

Answer 24

small, thin, Gram-, coccobacillus

Question 25

Whooping cough (B. pertussis): - (1) incubation period - (2) initial stage - (3) middle stage - (4) last stage - (5) communicable period

Answer 25

``` 1- 5-10 days (max 21 days) 2- Catarrhal stage, 1-2 wks (URI Sxs) 3- Paroxysmal stage, 1-6 wks 4- Convalescent stage, wks-mos 5- onset to 3 wks (bacteria is gone, but exotoxin keeps persistent Sxs) ```

Question 26

Bordetella pertussis virulence factors: - (1) responsible for bacterial attachment - (2) causes local tissue damage + bacterial proliferation - (3) is responsible for systemic toxicity

Answer 26

1- Protein Adhesins: pertactin, FHA (filimentous hemagglutinin), fimbria 2- dermonecrotic toxin, tracheal cytotoxin 3- pertussis toxin

Question 27

describe MOA of tracheal cytotoxin and pertussis toxin, how do they relate (B. pertussis)

Answer 27

Pertussis: inactivates adenylate cyclase --> inc cAMP --> inc respiratory secretions (mucus) Tracheal: prevents release of mucus secretions --> trapping it and causing whooping cough

Question 28

Bordetella pertussis must be sampled through (1) because of (2) property. (3) is the required agar because it is a fastidious organism. (4) can also be complete for evaluation of B. pertussis.

Answer 28

1- nasopharyngeal swab, or secretions 2- very susceptible to drying 3- charcoal blood agar + cephalosporin (aka Bordet-Gengou) 4- PCR

Question 29

describe the vaccines for bordetella pertussis

Answer 29

(DTaP, aP = acellular pertussis) 1) (rarely used) whole cell, formalin inactivated 2) *Acellular components (many): Fha, PT, pertactin, fimbriae-2/3 [lower rates of side effects] Note- immunity can dec over time