coryza

coryza / the common cold / viral rhinopharyngitis / rhinitis

introduction

  • the Common Cold or coryza is the most common infection to affect humans with adults having an average of 2-4 infections each year, and a child, 6-8 infections each year
  • it is self-limiting with most resolving in 7-10 days although many develop complications such as otitis media
  • they appear to be more frequent in cold weather, although the explanations for this have not been determined but could involve, lower immunity, lower humidity allowing droplets to spread further as aerosols, temperature-induced changes of resp. epithelium.

clinical features

  • incubation period is quite short, even as short as 16hrs from exposure
  • often subclinical infections
  • initial symptoms are mild fatigue, a feeling of being chilled, sneezing, and a mild headache
  • these soon develop into rhinopharyngitis with blocked nose, nasal discharge, sore throat and low grade fevers, peaking on day 2-4, and as post-nasal drip occurs, a productive cough usually develops
  • usually resolves in 7-10 days although the bronchitis and cough usually lasts an average of 18 days, while some develop a “post-viral cough” whic takes much longer to resolve
  • 90% are resolved within 15 days

DDx

  • see influenza for the differentiating features of coryza vs flu
    • if high fever, cough and severe headache occur then consider flu rather than coryza
  • pertussis (whooping cough) has an initial catarrhal stage similar to coryza before developing into the paroxysmal coughing after 1 week or two
  • measles starts with coryzal symptoms, cough, conjunctivitis BEFORE developing the rash
  • see also other causes of rhinitis
  • tonsillitis is primarily a sore throat, dysphagia and fever with minimal rhinitis or cough

aetiology

  • over 200 virus strains have been implicated and often more than one is detected
  • rhinoviruses (a picornavirus with many serotypes) account for 30-80%
  • human coronavirus 15%
  • influenza viruses 10-15%
  • adenovirus 10-15%
    • may cause conjunctivitis with tonsillitis, and types 40 and 41 may cause gastroenteritis, some may develop pneumonitis or, rarely, meningoencephalitis
    • nearly all children will be infected by age 2-3% and peak age is 2-3 months when it causes bronchiolitis; peak during the winter season
    • young adults are re-infected every 5-7years, elderly may have severe pneumonitis
    • incubation 2-8 days;
  • enteroviruses other than rhinoviruses
    • may cause non-specific febrile illnesses, sore throat, GIT symptoms and headache
    • Coxsackie B - may also cause myocarditis, pericarditis, meningitis, pancreatitis
    • enterovirus 68 - may also cause LRTI/wheeze and polio-like syndrome
  • human parainfluenza viruses
    • discovered 2001; a paramyxovirus family; usually winter, spring; incubation 3-6 days;
    • 2nd most common cause after Human orthopneumovirus (RSV) of lower respiratory infection in young children but has a slightly older peak age of 6-12 month of age (cf 2-3 months for RSV)
    • may progress to bronchitis or viral pneumonitis esp. if premature infeant, immunocompromised or elderly
    • almost all 5yr old have been exposed but reinfections are common including in adulthood
    • nearly as common and as severe as influenza in older adults

transmission

  • airborne droplet spread
  • direct contact with infected nasal secretions, or fomites (viruses can survive up to 18 hrs on fomites), and then transfer to eyes or nose

infectious period

  • rhinovirus-caused colds are most infectious during the first three days of symptoms, they are much less infectious afterwards 1)

prevention

  • maintain health
  • ensure adequate sleep
  • avoid people with colds, especially in closed spaces like crowded trains
  • frequent hand washing
  • face masks
  • herd immunity is important in limiting viral spread

Rx

  • supportive
  • analgesics / antipyretics but avoid aspirin as may increase risk of epistaxis
  • nasal decongestants used with care to avoid vasomotor rhinitis
  • encourage fluids
  • lip balm to reduce cracked lips and risk of re-activating a cold sore
  • take care when sneezing or blowing nose to minimise risk of secretions going to middle ear
  • take care with sneezing and coughing to avoid lumbar disc prolapse
  • avoid other people whilst in the early infectious stage
  • wash hands frequently to reduce fomite contamination
  • oral zinc acetate lozenges not exceeding 100mg elemental zinc/ day appears to reduce duration of nasopharyngeal symptoms by 3 days if started on day one, suggesting it may be a local surface effect rather than a systemic effect 2)
  • oral vitamin C in high doses may reduce severity / duration of symptoms by 15-26% 3)
  • there are no vaccines or antivirals effective for the common cold

potential complications

  • sinusitis in 30%
  • bacterial conjunctivitis
  • re-activation of Herpes simplex virus (HSV) cold sores
  • epistaxis - especially if on antiplatelet agents such as aspirin, clopidogrel, or on anticoagulants
  • exacerbation of asthma
  • post-viral cough
  • slipped lumbar disc from coughing or sneezing bouts
coryza.txt · Last modified: 2023/12/13 12:00 by gary1

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