Pertussis

Question 1

Causative organism of pertussis

Answer 1

Bordetella pertussis

Question 2

Spread of pertussis

Answer 2

Resp. droplet

Question 3

Risk factors for pertussis

Answer 3

• Age < 6 month
• Baby born to mother who became infected at≥34 weeks gestation
• No or incomplete immunisation
• High-risk groups for Tx
• School teachers or HCW
• Close contacts
• Household contacts

Question 4

Natural Hx of pertussis

Answer 4

• Incubation period 6-20 days

• Prodromal catarrhal stage (1-7d):
  
  • URTI Sx (coryza, mild cough, sneezing) with no or low-grade fever
• Paroxysmal stage (lasts 4-6 weeks):
  
  • characterised by paroxysms of cough, sometimes followed by inspiratory whoop
  • Attacks may be precipitated by yawning, sneezing, eating, physical exertion
  • May have post-tussive emesis
  • Infants may have post-tussive apnoea
• Convalescent stage (lasts 1-2 weeks):
  
  • occasional paroxysms of cough, but decreased frequency and severity
  • Non-infectious but cough may last up to 6/12

Question 5

When is pertussis most contagious? When is an index case contagious?

Answer 5

• Most contagious during prodromal, catarrhal stage

- An index case is considered infectious if <21 days cough or <5days effective abx treatment

Question 6

What are some possible complications of pertussis? Who is at greatest risk?

Answer 6

Infants < 6mo greatest risk of complications:
• Pneumonia-> respiratory failure -> ?death
• Bronchiectasis
• Seizure: likely due to cerebral hypoxia secondary to severe paroxysms of cough
• Apnoea/bradycardia
• Encephalopathy
• Rib fracture

*Bacteraemia doesn’t occur

Question 7

Ix for pertussis

Answer 7

Not needed (NPA swab for PCR if needed)

Question 8

Clinical Dx criteria for pertussis

Answer 8

Cough lasting at least 2 weeks with at least one of the following symptoms:
• Paroxysms of coughing
• Inspiratory whooping
• Post-tussive vomiting without other apparent cause

• NB: Pertussis can also present as a non-specific persistent cough
• NB: Whoop often absent in infants

Question 9

Prevention of pertussis

Answer 9

Vax - 85% effective. Wanes after 6-10y.

Question 10

Mx of pertussis

Answer 10

• Abx maybe
• Exclusion until 5 days Abx/coughing for > 21 days
• Vax 3 dose
• Notifiable
• Treat close contacts - abx, vax, exclusion

Question 11

When to admit pertussis?

Answer 11

• <6mo

- Complications e.g. apnoea, cyanosis, pneumonia, encephalopathy

Question 12

When would you consider using abx in pertussis?

Answer 12

○ Diagnosed in catarrhal or early paroxysmal phase (may reduce severity)
○ Cough for less than 14 days (may reduce spread; reduces school exclusion period)
○ Admitted to hospital/complications