42. Respiratory Tract Infections Flashcards
upper vs lower respiratory tract?
upper has bacteria lower is normally sterile
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
otitis media pathogenesis?
- eustacian tube obstruction
- air absorbed into middle ear (low pressure)
- fluid collects
- bacteria proliferate
- release of inflammatory mediators
acute otitis media epidemiology?
common in young kids
peak during URI season
RFs: fam hx, prematurity, anatomic abn, immune defic, group daycare, secondhand smoke
AOM signs and sxs?
non specific:
- fever
- irritability, headache, anorexia, vomiting, diarrhea
local signs:
- otalgia
- otorrhea
- hearing loss
AOM vs OME?
AOM:
- symptomatic
- tx w/Abx
- more inflammatory
OME: (otitis media w/effusion)
- present 1-3 months after AOM
- asymptomatic
- no Abx
AOM bugs?
S. pneumoniae
H. influenzae
M. catarrhalis
Rx for AOM?
Amoxicillin (high dose for S.pneumo altered PBP) maybe w/clavulanate if suspect H.flu (eg conjunctivitis)
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
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
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)
sinusitis pathogens in kids?
S.pneumoniae
H.influenzae (non-typeable)
M. catarrhalis
chronic sinusitis bugs?
staphylococci
anaerobes
haemophilus
pneumococcus
moraxella
etc
dx of sinusitis?
clinical exam
sinus aspiration
radiograph or CT (fro recurrent episodes, suspected complications, unclear diagnosis)
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
complications of sinusitis?
orbital cellulitis
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
GAS pharyngitis clinical manifestations?
FEVER
headache, abdominal sxs
exudative pharyngitis
tender cervical lymphadenopathy
scarlet fever rash
ABSENT cough, coryza, conjunctivitis
GAS dx?
throat swab
rapid strep test
if ^^ negative, do cx
judicious use of Abx in pharyngitis?
clinical suspicion AND lab testing
don’t treat presumptively
PCN = drug of choice
strep pharyngitis complications?
suppurative: peritonsillar abscess, retropharyngeal abscess
nonsuppurative: acute rheumatic fever (preventable), glomerulonephritis
pna epi?
extremes of age most susceptible
6th leading cause of death in the US
2-3 million adults affected annualy
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)
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
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
bacterial pna characteristics?
abrupt onset
high fever
low or high WBC (15K)
neutrophil predominance w/bands
lobar dist
higher risk for empyema
bacterial pna pathogens?
s. pneumoniae
h. influenzae
s. aureus
bacterial pneumonia dx by culture?
- blood culture positive in bacterial pneumonia
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
atypical pna pathogens?
viruses
M. pneumoniae
C. pneumoniae
L. pneumophila
mycoplasma pneumoniae?
common cause of atypical pneumonia
special features:
- rash
- cold agglutinins (50-70%)
dx w/serologies of cold agglutinins
treat w/ MACROLIDES
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
severe pna characteristics?
rapidly progressive
ANTECEDENT INFLUENZA INFECTION (S.aureus)
effusion, empyema, pneumothorax
pneumatoceles (usu develop later)
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
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
