Whooping cough

Background

  • Also known as pertussis
  • Highly infectious disease caused by Bordatella pertussis
    • Produces pertussis toxin
    • Incubation usually around 7 days; spread via aerosol droplets; infectious for 3 weeks after initial symptoms
  • Fortunately infrequent (1 in 1000 per year during ‘peak year’ which recur every 3-5 years) in the UK due to vaccination (DTaP at 2, 3, 4 months)
    • More common in infants who have not yet received full vaccination (or unvaccinated)

Presentation

  • 3 phases of infection
    • catarrhal phase
      • dry, unproductive cough; may be preceded by prodromal symptoms typical of URTI (up to 7 days)
    • Paroxysmal phase
      • whooping (inspiratory gasp- may not be seen in adults), post-tussive (cough) vomiting is common in infants, generalised symptoms (can last a month or more)
      • between coughing fits, the patient is generally well
      • coughing fits are more common at night, can be triggered by cold/noise
        • in adults there may be associated autonomic features e.g. sweating, flushing; in children, it can cause cyanosis
    • Convalescent phase
      • Gradual improvement (can take 2+ months)
  • NB Pertussis is a notifiable disease

Investigations

  • Most cases are clinical diagnoses; but health protection may request laboratory confirmation via
    • nasopharygeal aspirate/swab
    • antipertussis toxin IgG
    • PCR positive

Management

  • Consider admission to those who are seriously unwell e.g. cyanotic, apnoea, trouble breathing
    • Low threshold in infants <6 months
    • Particularly in cases with complications e.g. pneumonia
  • Consider antibiotic treatment (macrolide- clarithromycin in <1 month; azithromycin + clarithromycin in older infants/children/adults; erythromycin in pregnancy) if symptoms started within 21 days
    • Important to treat in pregnancy to prevent transmission
  • Health protection can consider offering antibiotic prophylaxis to those at risk (priority group) contacts e.g. those with pregnant women or baby in household.  Also offer immunisation
Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

w

Connecting to %s