42. Respiratory Tract Infections Flashcards Preview

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Flashcards in 42. Respiratory Tract Infections Deck (35):
1

upper vs lower respiratory tract?

upper has bacteria lower is normally sterile

2

the respiratory system actively clears infectious particles...give role of each:
- nares
- epiglottic reflex
- cough
- mucus secreting and ciliated cells
- alveolar macrophages
- nonspecific and specific immune response
- lymph

- nares: filtration
- epiglottic reflex: prevents aspiration
- cough: particle expulsion
- mucus secreting and ciliated cells: entrap and expel particles
- alveolar macrophages: ingest and kill bacteria
- nonspecific and specific immune response: antibodies, opsonins, complement
- lymph: drainage

3

otitis media pathogenesis?

1. eustacian tube obstruction
2. air absorbed into middle ear (low pressure)
3. fluid collects
4. bacteria proliferate
5. release of inflammatory mediators

4

acute otitis media epidemiology?

common in young kids

peak during URI season

RFs: fam hx, prematurity, anatomic abn, immune defic, group daycare, secondhand smoke

5

AOM signs and sxs?

non specific:
- fever
- irritability, headache, anorexia, vomiting, diarrhea

local signs:
- otalgia
- otorrhea
- hearing loss

6

AOM vs OME?

AOM:
- symptomatic
- tx w/Abx
- more inflammatory

OME: (otitis media w/effusion)
- present 1-3 months after AOM
- asymptomatic
- no Abx

7

AOM bugs?

S. pneumoniae
H. influenzae
M. catarrhalis

8

Rx for AOM?

Amoxicillin (high dose for S.pneumo altered PBP) maybe w/clavulanate if suspect H.flu (eg conjunctivitis)

9

mastoiditis?

complication of AOM

- middle ear cavity and mastoid ear spaces are continuous

- purulent material accumulates in the mastoid cavities
- boggy, swollen mastoid
- ear displaced

= osteomyelitis

10

sinusitis vs common cold

common cold:
- viral
- rhinorrhea
- getting better in a week

sinusitis:
- bacterial infection of paranasal sinuses
- Abx
- rhinorrhea
- localizing signs to sinus area
- severe headache or focal pain
- ill and highly febrile for a long time
- sinusitis has a longer duration

11

sinusitis risk factors?

obstruction
- URI, allergy, foreign body

impeded ciliary function
- URI, immotile cilia syndrome

Abn mucous production
- URI, CF, decongestant use

immunodeficiency

breach of sinuses (cleft palate, dental infections, swimming)

12

sinusitis pathogens in kids?

S.pneumoniae
H.influenzae (non-typeable)
M. catarrhalis

13

chronic sinusitis bugs?

staphylococci
anaerobes

haemophilus
pneumococcus
moraxella

etc

14

dx of sinusitis?

clinical exam

sinus aspiration

radiograph or CT (fro recurrent episodes, suspected complications, unclear diagnosis)

15

tx of acute sinusitis?

spontaneous resolution 4-60%

kids: amoxicillin +/- clavulanate

adults: amox/clav or cephalosporin or quinolone (coverage of S. aureus more impt in adults)

expect improvement in 2-3 days (otherwise re-eval)

IV abx for severe disease

16

complications of sinusitis?

orbital cellulitis

17

pharyngitis epi?

viral infection is 90% (self-limiting and no tx necessary)

common pathogen in bacterial: S. pyogenes

pharyngitis caused by S. pyogenes primarily effects ppl 5-10 y/o

18

GAS pharyngitis clinical manifestations?

FEVER

headache, abdominal sxs

exudative pharyngitis

tender cervical lymphadenopathy

scarlet fever rash

ABSENT cough, coryza, conjunctivitis

19

GAS dx?

throat swab

rapid strep test

if ^^ negative, do cx

20

judicious use of Abx in pharyngitis?

clinical suspicion AND lab testing

don't treat presumptively

PCN = drug of choice

21

strep pharyngitis complications?

suppurative: peritonsillar abscess, retropharyngeal abscess

nonsuppurative: acute rheumatic fever (preventable), glomerulonephritis

22

pna epi?

extremes of age most susceptible

6th leading cause of death in the US

2-3 million adults affected annualy

23

define:
pna?
pneumonitis?
effusion?
empyema?

pna: inflammation and consolidation of the lung (alveolar unless otherwise specified)
- lobar
- lobar or bronchial
- interstitial

pneumonitis: inflammation of the lung

effusion: fluid

empyema: exudate or pus (WBC, fibrin, serum)

24

signs and sxs of pneumonia?

respiratory:
- tachypnea (infant w/RR = 60)
- cough and sputum production
- dyspnea and work on breathing: flaring, grunting, retractions
- crackles
- tubular (decreased) breath sounds
- dullness to percussion
- increased (or decreased) vocal fremitus (toy truck)

nonspecific:
- FEVER
- headache
- malaise
- GI complains

pain:
- pleuritic
- referred

25

risk factors for bacterial PNA?

anatomic:
- tracheo-esophageal fistula
- sequestration of lung

aspiration
- reflux
- comatose state
- anesthesia

alterations in mucous clearance
- CF

immunodeficiency

nosocomial exposure

26

bacterial pna characteristics?

abrupt onset

high fever

low or high WBC (15K)

neutrophil predominance w/bands

lobar dist

higher risk for empyema

27

bacterial pna pathogens?

s.pneumoniae
h. influenzae
s.aureus

28

bacterial pneumonia dx by culture?

- blood culture positive in bacterial pneumonia

29

atypical pneumonia characteristics?

school-aged kids

"walking pna"

subacute onset

"flu-like" sxs

extrapulmonary sxs

normal or high WBC w/LYMPHOCYTE PREDOMINANCE

CXR w/ diffuse and/or interstitial involvement

30

atypical pna pathogens?

viruses
M. pneumoniae
C. pneumoniae
L. pneumophila

31

mycoplasma pneumoniae?

common cause of atypical pneumonia

special features:
- rash
- cold agglutinins (50-70%)

dx w/serologies of cold agglutinins

treat w/ MACROLIDES

32

legionella pneumophila?

legionnaire's disease

fear the severe presentation!
- progressive even when on abx
- prevelant pna in the ICU

age >50

aerosolized water droplets

EXTRAPULMONARY MANIFESTATIONS

SPUTUM PURULENT w/NO ORGANISMS

urine legionella Ag test

tx w/MACROLIDES

33

severe pna characteristics?

rapidly progressive

ANTECEDENT INFLUENZA INFECTION (S.aureus)

effusion, empyema, pneumothorax

pneumatoceles (usu develop later)

34

severe pneumonia causes?

S. pneumo is the most common cause of bacterial pneumonia, incl severe pna, but in a hospitalized pt, worry about S.aureus and CA-MRSA

atypical pathogens, esp legionella, can also cause severe pna, so in the ill pt, empiric tx should cover both typicals and atypicals

35

CA-PNA tx?

outpt, low risk:
- previously healthy, no abx in past 3 months
- bugs: S. pneumo, H. flu, Mycoplasma
- Abx: Azithromycin

outpt, high risk or inpt:
- comorbidities, abx in past 3 months
- bugs, same but greater concern for macrolide resistant S.pneumo
- Abx: use a new class of drug, respiratory flouroquinolone OR azithromycin plus beta-lactam

ICU:
- bugs: all others PLUS legionella, MRSA...if immunosuppressed maybe pseudomonas & gram (-) orgs
- abx: 3rd generation cephalosporin or ampicillin/sulbactam PLUS respiratory fluoroquinolone OR azithromycin, consider vanc, consider pseudomonas coverage