Red Whale update - Diphtheria cases in the UK

 

Possible outbreak of this serious infectious disease?

 
Red Whale

 
2 cases of diphtheria in the news this November

In November 2019 reports emerged of 2 adults in the UK diagnosed with diphtheria, triggering widespread panicked headlines talking of possible ‘outbreaks’ of this serious infectious disease.

In fact, both these cases were in people recently returned from travel abroad, and there were no reported cases of transmission within the UK.

However, these cases do raise an interesting question for us in primary care. With falling vaccination rates in our population, it is possible we may see more cases of diphtheria in people returning from travel abroad. Many of us will never have seen a case in our careers, so we thought it might be handy to remind ourselves of the facts! (Public Health England 2014 guidance on the control and management of diphtheria).

Diphtheria is an acute infectious disease triggered by a Corynebacterium. Whilst rare in the UK due to high vaccination rates, it remains prevalent in other parts of the world. It is a serious illness with a mortality rate of around 5-10%.

 
 
 
How do we diagnose and manage diphtheria?

Incubation: 2-6 days. During incubation asymptomatic patients may be infectious.

Transmission: droplet spread by sneezing/coughing or direct contact.

The usual presentations are:

  • A pharyngitis and acute upper respiratory tract infection:
    • Enlarged anterior cervical lymph nodes: a bull neck.
    • Low grade fever, sore throat and malaise
    • Pseudomembranous pharyngitis: a classic textbook appearance that may not be seen in vaccinated individuals with less severe infection. Initially a white shiny coating over the pharynx and uvula this can later turn grey or even black, and bleeds when touched. If severe it can cause respiratory obstruction.
    • Laryngeal involvement: hoarse voice, cough, even stridor.
       
  • Skin manifestation:
    • Usually only seen in the tropics or in very disadvantaged populations at high risk.
    • Purulent blisters on feet and legs.  
    • Ulceration of affected skin.
    • Cardiac complications: around ½ of all deaths from diphtheria are due to cardiomyopathy or myocarditis.

Diagnosis:

  • Usually made on throat swabs, or clinically.
  • If diphtheria is suspected - discuss with local infectious disease teams on the same day.
  • Diphtheria is a notifiable disease so public health should also be informed.

Management:

  • Antibiotics: clarithromycin, azithromycin or penicillin. Treatment courses 2-4 weeks.
  • Severe cases requiring hospitalisation should also be given diphtheria anti-toxin.
  • Any contacts should be swabbed, and all contacts and identified carriers should be given 1 week antibiotic clearance.
  • Quarantine should continue until: antibiotic course complete PLUS at least 2 separate throat swabs taken at least 24 hours apart AND at least 24 hours after completion of antibiotics are returned clear.
 
 
 

Dirty white pseudomembrane classically seen in diphtheria

 

 

Then, what about after the patient recovers?

 

After recovery:

  • Any partially vaccinated patients should complete the usual UK immunisation schedule.
  • Individuals up to date with the usual vaccination schedule should have a booster vaccine.

Hopefully, we will never see a case…but if we do, we might have a chance of spotting it now and knowing what to do!

 
Kind regards,
The Red Whale Team
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