3: Respiratory ID

Question 1

7 features of resp tract anatomy that help rid system of pathogens

Answer 1

Mucociliary lining of nasal cavity, change of direction of airway from sinuses to pharynx (adenoids), ciliary elevator, normal flora competition (staph), alveolar macrophages, IgA, nasal hair

Question 2

2 main obstacles microorganisms must overcome

Answer 2

Avoid mucus layers or survive in it (and get swallowed), avoid phagocytosis or survive in phagocytic cell

Question 3

What is the role of turbinate bones (“baffle plates”)?

Answer 3

-> air swirling forcing contact w mucus covering

Question 4

How does the mucociliary escalator work? Where is it?

Answer 4

Covers most of bronchi, bronchioles and nose. Mucus producing goblet cells + ciliated epithelium.

Question 5

What effect does smoking have on the mucociliary escalator?

Answer 5

Paralyzes cilia -> higher rate of infection. They do regrow after cessation.

Question 6

Normal biota of the lower respiratory tract

Answer 6

None (sterile)

Question 7

Conditions that must be met to establish respiratory tract infection (4)

Answer 7

1 sufficient dose inhaled 2 airborne infectious particles 3 particles viable in air 4 deposited on tissue susceptible to infection

Question 8

Most common microorganism for the common cold (rhinitis)

Answer 8

Almost exclusively viral, most commonly Rhinovirus

Question 9

Sinusitis most common microorganisms

Answer 9

Bacterial secondary infections, usually S. pneumo and H. flu

Question 10

Pharyngitis most common microorganisms

Answer 10

90% viral. Important bacterial: S. pyogenes, C. diphtheriae

Question 11

Laryngitis/croup most common microorganisms

Answer 11

Mostly viral, parainfluenza virus and respiratory syncitytial virus (RSV)

Question 12

How is it that you can get infections by rhinovirus (common cold) year after year?

Answer 12

100-200 distinct rhinoviruses, 50 distinct adenoviruses, several types of coronavirus

Question 13

When might there be a cough with a common cold?

Answer 13

When infection makes its way to the lower respiratory tract

Question 14

How is the common cold spread?

Answer 14

Hand to hand contact, fomite transmission

Question 15

How does rhinovirus infect the nasal passages?

Answer 15

attaches to ICAM-1 -> localized inflammation and lytic infection -> ciliated epith cells destroyed

Question 16

When do symptoms peak in rhinitis?

Answer 16

2-5 days, cells completely regenerated day 14

Question 17

Why might nasal secretions change from clear to purulent during rhinitis?

Answer 17

Clear = initial rhinitis, purulent= secondary bacterial infection by normal flora

Question 18

Treatment of rhinitis

Answer 18

supportive therapy

Question 19

Rhinovirus classification: genoma, nucleocapsid, envelope, family

Answer 19

Class IV: ssRNA(+) non-segmented, icosahedral nucleocapsid, non-enveloped, picornaviridae family

Question 20

Paramyxovirus/ parainfluenza virus classification: genome, nucleocapsid, envelope, family

Answer 20

Class V: ssRNA (-) non-segmented, helical nucleocapsid, enveloped, paramyxoviridae family

Question 21

Coronavirus classification and examples (2)

Answer 21

Class IV: ssRNA+, helical nucleocapsid, enveloped, coronaviridae family. E.g. SARS and MERS

Question 22

Influenza classification

Answer 22

Class V: segmented ssRNA-, helical, enveloped, orthomyxoviridae

Question 23

Coxsackievirus classification

Answer 23

Class IV: ssRNA+, icosahedral, nonenveloped, picornaviridae family - enterovirus

Question 24

Adenovirus classification

Answer 24

Class I: dsDNA, icosahedral, non-enveloped

Question 25

Definition of acute rhinosinusitis. How long does the infection last?

Answer 25

Inflammation or infection of the mucosa of nasal passages + at least one of the paranasal sinuses. Lasts no longer than 4 weeks.

Question 26

Most common causes of community acquired acute bacterial rhinosinusitus?

Answer 26

Streptococcus pneumoniae, haemophilus influenzae.

Question 27

Two less common pathogens for rhinosinusitis

Answer 27

Strep pyogenes, staph aureus

Question 28

Presentation of sinusitis

Answer 28

Common cold 1 week prior. sneezing, rhinorrhea, congestion w postnasal drip, HA, sore throat, cough, fever, muscle aches

Question 29

Fungal sinusitis common pathogen

Answer 29

Aspergillus fumigatus

Question 30

Treatment of fungal sinusitis

Answer 30

Immunocompetent: mechanical removal. Immunocomp: can lead to eye and brain involvement

Question 31

Most common cause of rhinosinusitis (general)

Answer 31

Viral

Question 32

Rhinosinusitis course

Answer 32

Frequently a cold one week prior followed by a couple days feeling improved -> wake up w sx. Most resolve in 5-7 days without treatment.

Question 33

Treatment of rhinosinusitis

Answer 33

Most resolve w/o tx 5-7 d. Symptomatic or antibiotics for bacterial.

Question 34

Potential ways to differentiated between viral and bacterial rhinosinusitis

Answer 34

Bact: mod sx 7 days out (10-14 for kids) or severe sx (inc facial swelling, tooth pain, fever >39/ 102).

Question 35

Treatment of sinusitis

Answer 35

Oral hydration w saline nasal washes, steam, acetaminophen and decongestants, mucolytics. Abx: amoxicillin (augmentin) or azithromycin

Question 36

S pneumo classification include Bile-esculin and optochin statuses.

Answer 36

Gram + diplococci, cat -, alpha hemolytic, bile-esculin neg, optochin susceptible

Question 37

H influenzae classification

Answer 37

Gram neg coccobacilli (pleomorphic), X&V factors required

Question 38

Most pharyngitis is caused by (general)?

Answer 38

Viruses

Question 39

Most common bacterial cause of acute pharyngitis

Answer 39

strep pyogenes

Question 40

Pharyngitis presentation

Answer 40

Fever, sore throat, edema, hyperemia of tonsils and pharyngeal walls

Question 41

What findings in pharyngitis suggest a viral cause?

Answer 41

Conjunctivitis, cough, hoarseness, inflammation of mucus membrane, diarrhea

Question 42

Pharyngitis patients w Strep pyogenes presentation

Answer 42

Fever & SEVERE pain w swallowing, sudden onset. May also have HA, n/v, abd pain, red tonsils w or w/o exudate, enlarged tender cerv lymph nodes

Question 43

Why are strep pyogenes infections treated with antibiotics?

Answer 43

Prevent glomerulonephritis and rheumatic fever.

Question 44

Strep pyogenes pharyngitis: treatment would start within how many days?

Answer 44

9

Question 45

S. pyogenes pharyngitis most common in what population? What time of year?

Answer 45

age 5-15, winter and spring

Question 46

Spread of pharyngitis

Answer 46

person to person and via fomites

Question 47

Viral pharyngitis: how does infection begin?

Answer 47

Virus gains access to mucosal cells lining the nasopharynx, replicates -> damage to host cells

Question 48

Bacterial pharyngitis: how does infection begin? (2 invasion virulence factors) What does it use for attachment? (3)

Answer 48

S. pyogenes attaches to mucosal epithel. cells using M protein, lipoteichoic acid, and fibronectin-binding protein. Invasion w protease and hyaluronidase.

Question 49

Treatment of pharyngitis

Answer 49

Supportive care. Viral: acetaminophen + warm saline gargles. S pyogenes: penicillin

Question 50

What should be used instead of penicillin for pharyngitis patients allergic to penicillin?

Answer 50

erythromycin

Question 51

S. pyogenes classification inc bacitracin status

Answer 51

Gram+ cocci, tends to grow in chains. Cat neg, beta hemolytic, bacitracin sensitive.

Question 52

C. diphtheriae classification

Answer 52

Gram + bacilli, non-spore forming, non-motile

Question 53

Etiology of scarlet fever

Answer 53

Certain strains of S. pyogenes -> superantigens - streptococcal pyogenic exotoxins A (SpeA), SpeB, SpeC, and SpeF. Encoded by lysogenized bacteriophage (not bacteria itself)

Question 54

Presentation of scarlet fever

Answer 54

Strawberry tongue, bright red rash.

Question 55

Difference between peroxidase and catalase

Answer 55

O2 + H2O2 Peroxidase: -> H2O (no oxygen, catalase neg) Catalase: -> H2O + O2

Question 56

How does strep deal with H2O2?

Answer 56

Peroxidase (no O2 formation = no bubbles in catalase test)

Question 57

Diphtheria infection on a microscopic level

Answer 57

Diphtheriae produce potent A-B toxin (B binds -> endocytosis -> A has enzymatic activity

Question 58

Why should you avoid scraping the pseudomembrane (gray adherent plaque) that forms with diphtheria?

Answer 58

Introduce toxin to blood stream -> myocarditis, neuritis (temp paralysis of limbs, soft palate, and diaphragm).

Question 59

Presentation of croup

Answer 59

fever of 38-39 (100.4- 102.2), restlessness, shortness of breath. Usually begins with cold-like sx, nasal cong, sore throat, cough lasting 2-3 d. Then harsh bark-like cough. Respiratory stridor at night.

Question 60

Severe croup presentation

Answer 60

Insp stridor at rest, nasal flaring, suprasternal and intercostal retractions, tachypnea, tachy out of proportion to fever, pallor, hypotonia, lethargy

Question 61

Hypoxemia in croup -->

Answer 61

Lethargy or agitation.

Question 62

Ominous sign in croup

Answer 62

cyanosis

Question 63

Peak of symptoms and time to resolve

Answer 63

Peak: 3-5 d, resolve 4-7.

Question 64

How is croup transmitted?

Answer 64

Person to person contact

Question 65

Timing of croup including specifics of pararinfluenza, influenza, and RSV

Answer 65

Parainfluenza: any time of year. Influenza and RSV: winter and early spring

Question 66

Treatment of croup

Answer 66

Usually self-limited, symptomatic tx

Question 67

Most common cause of pneumonia in young children (2)

Answer 67

RSV, parainfluenza virus

Question 68

Enteroviruses are a member of the picornaviridae family. What are some groups that constitute enteroviruses?

Answer 68

Echo, Coxsackie A&B, poliovirus

Question 69

After rhinovirus, other common causes of rhinitis

Answer 69

Adenovirus, Coxsackie A&B + influenza C are minor causes

Question 70

Rhinoviruses: associated disease

Answer 70

common cold

Question 71

Coronaviruses: associated disease

Answer 71

Common cold

Question 72

Adenoviruses: associated disease and occurrence

Answer 72

Pharyngoconjunctival fever and acute resp disease. Military recruits and boarding schools.

Question 73

Parainfluenza virus: associated disease and occurrence

Answer 73

Cold and croup. Common in children.

Question 74

Influenza A&B: associated disease and occurrence

Answer 74

Influenza, common during flu season

Question 75

RSV: associated disease and occurrence

Answer 75

Bronchiolitis and croup, common in children

Question 76

EBV: associated disease and occurrence

Answer 76

Infectious mono, common in adolescents during winter

Question 77

RSV classification

Answer 77

Class V: ssRNA- nonseg, enveloped, helical nucleocapsid, paramyxoviridae family, pneumovirus - RSV

Question 78

How does RSV appear histologically? Why?

Answer 78

Giant cells: F protein of RSV causes nearby cell membranes to fuse.