Upper Respiratory Tract Infections Flashcards
Most common Infections of URT
Cold
Pharyngitis
Tonsillitis
Sinusitis
Common viruses
Adenovirus
Parainfluenza virus
Rhinovirus
Nasopharyngitis
Rhinopharyngitis #1 cause of acute illness worldwide
Nasopharyngitis Aetiology
30-50% caused by rhinovirus
10-15% coronavirus
Nasopharyngitis Transmission
Inhaling droplets
Can survive 3 hours outside nose
Rhinovirus incubation time
1-5 days
Nasopharyngitis Pathophys
Virus binds to host cell Releases genetic material inside cell Replication of genetic material + transcription of protein packaging into viruses New viruses ready to infect
Nasopharyngitis major symptoms
Rhinorrhea (mucus filling nose) Nasal obstruction Sore throat Cough Sneeze
Human Rhinovirus Pathophys
HRV infection of airway epithelial cell
Recognised by Toll like receptor 3
Airway bronchial epithelial cells release pro inflammatory mediators
Promote recruitment + activation of inflammatory cells
Clearance of virus
Respiratory Syncytial Virus (RSV) Pathophys
Viral replication
Viral RNA recognised through TLR3 + RIGI like receptors
Pro inflammatory mediators
Type I IFN upregulate pro-apoptotic factors in epithelial cells
TNF alpha + chemokines recruit NK cells + PMN that kill infected cells
Rhinorrhoea + nasal obstruction causes
Neutrophilic inflammation
–> increased vascular permeability + mucus hypersecretion
Virus impedes immune recognition
Release of soluble form of G protein
Rhinovirus effect on asthma
50-80% asthma exacerbations
Factors favouring HRV infection severity in allergic conditions
Asthma
Increased cytokine release
Increased intracellular adhesion molecule
Management Nasopharyngitis symptoms
Decongestants- decrease swelling of blood vessels around nose, decrease congested nose
Cough suppressants
Antiseptics
Painkillers
