CR - Upper RTIs (i)
intro
most common infectious agents in general pop, esp in young children
main reason for missing work/school
wide spectrum of severity from common cold to life threatening epiglottitis
mostly viral (esp in winter)
upper resp tract = nasal cavity, pharynx, larynx
incl common cold, sinusitis, otitis media, pharyngitis, diphtheria, laryngitis, epiglottitis, laryngotracheobronchitis (croup)
overlap in causative agents
some progress to lower RTI (trachea, bronchi, lungs)
Normal upper resp tract flora
S pneumoniae
Haemophilus spp (e.g. H Influenzae)
S aureus
N meningitides + lactamica + polysacchareae
anaerobic + microaerophilic strep
S anginosus
prevotella melanginogenieus
diphtheroids
coag -ve staph
abundance, hence sputum sample will always grow something (consider this when interpreting culture results)
defence mechanisms
physical + mechanical
hair
cilia
mucus
commensals
lysozyme-containing saliva
IgA - humoral immunity
innate immunity
macrophages
neutrophils
monocytes
eosinophils
infection sources
exogenous
endogenous
case
carrier
environment
own flora
aspiration
Risk factors
age
children bear the heaviest burden - infected 3-8 times/yr, adults 2-4, over 60s less than once a yr
gender (nasal mucosal swelling during ovulation-peaked oestrogen)
seasonalilty (RSV, influenza, GAS peak in winter)
societal factors (e.g. overcrowding in childcare facilities)
contact with cases/carrier
travel
TB
diphtheria (vaccine-preventable, but breakdown in immunisation programmes in conflict zones)
smoking (incl passive)
predisposing anatomical lesions/abnormalities
carrier states (e.g. some people are colonised with S aureus, some aren't)
pharyngitis mostly in 4-7 y/os
epiglottitis peaks in 3 y/os (2-7)
caused by haemophilus
vaccine preventable so not seen much in Ire
laryngitis + croup peak in 2 y/os (6months-6yrs)
overwhelm paed department
spread
droplet
fomites
direct
coughing/sneezing
wear mask
large particles settle quickly, small ones remain airborne for 1-2hrs
tissue/bed linen
esp viruses
some bacteria remain alive on these for wks/months (TB, staph, strep)
hands
intubation
instrumentation
common cold
predominantly viral (not part of normal flora)
vast no. of serotypes - frequent changes in antigenicity
coryza/rhinitis, sore throat, cough
caused by rhinoviruses, coronaviruses, RSV
ILI
more systemic symptoms
high fever for a few days
malaise
headache
sore throat
rhinitis
rigors
myalgia
causes: influenza virus (staff should be vaccinated to protect patients), more rarely parainfluenza or adenoviruses
distinguishing allergy
itchy water eyes indicates allergy (but could be conjunctivitis caused by adenovirus)
effects of colds
time off work/school
GP visits
antibiotic misuse (Tx usually only needs to be symptomatic)
hospitalisation
morbidity + mortality
outbreaks
Croup
clinical Dx
must rule out epitglottitis (acute + no cough)
if hospitalised give humidified O2 + corticosteroids
common in childhood
viral (influenza, parainfluenza, RSV)
may be post upper RTI
SOB, inspiratory stridor, seal-like cough
inflamm of larynx + trachea