Upper Respiratory Tract Infections

In the last week it feels like I've seen more URTIs than I've had my lifetime! URTI is the posh word for the common cold. Because the ambient temperature is lower in winter the viruses involved survive for longer in droplets in the air so are more readily transferred between hosts. Needless to say one of my patients seems to have already given me a cold!

So what causes an URTI?

Most are caused by starins of the rhinovirus group (picornaviruses) although the list of causative viruses is long and includes adenoviruses, coronaviruses, coxsachie viruses, echoviruses, influenza and parainfluenza viruses and RSV.

If the larynx, trachea and major bronchi are affected the likely viruses are the adenoviruses, influenza and parainfluenza (I & II) viruses and RSV.

Symptomatic Relief

The debate over antibiotics will probably never end but there is no clear benefit of using antibiotics for URTIs because the cause is viral. Possibly they shorten the duration of illness by 24 hours but they always carry the risk of side effects and resistance. In cases of a proven secondary bacterial infection they are of course indicated and also probably in patients who are not improving after a couple of weeks.

This leaves us with treatments that target the symptoms rather than the cause which the body will fight in due course.

• Steam inhalation (and spicy foods!)
  • loosens mucous so cleared more easily
    • can reduce cough due to postnasal drip
    • can improve sinus pain and earache as they drain better
• Decongestants (norephedrine, oxymetazoline, or pseudoephedrine)
  • helpful for up to 10 hours
  • nasal vasoconstrictor leads to reduced oedema and mucous production
    • helps sinus pain and earache by opening up eustacian tubes and sinus ostia so improving drainage
  • no more than 2 weeks as withdrawal can then make things much worse (rhinitis medicamentosa)
  • can cause tachyarrhythmias
• Paracetamol +/- NSAID
  • good for aches and pains and for reducing fever
• Cough suppressants (antitussives)
  • theoretically increase chance of sputum retention and chest infection but good symptomatic relief
    • not in very young or in COPD sufferers
  • dextromethorphan
    • cough suppressant, not addictive
  • diphenhydramine (Bronylin)
    • cough suppressant, antihistamine (sedative & decongestant) and anticholinergic (dries up secretions)
  • combination of above = Benylin Dry Cough
  • opiates
    • powerful cough suppressants but chance of addiction
• Mucolytics
  • no help, reserved for chronic asthma and COPD

Complications

Sinusitis and otitis media are probably the most common complications of the common cold. They both should resolve with conservative management but occasionally require antibiotics if not settling after 2 weeks. Otitis media sometimes leads to rupture of the typanic membrane which would lead to a resolution of pain followed by purulent fluid from the ear.

Those with asthma and COPD often suffer exacerbations (it may herald the diagnosis) and this should be treated with steroids and antibiotics (commonly amoxicillin) if there is any reason to suspect bacterial infection.

Occasionally a common cold leaves patients simply more vulnerable to a LRTI (ie pneumonia) which should be treated with antibiotics. This would be suspected if they are not getting better for over a week, are short of breath, coughing up purulent sputum or compain of pleuritic chest pain. Auscultation of the chest should demonstrate signs of consolidation but if the history is convincing do not rely on the absence of crepitations!