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