Whooping cough

Question 1

Define

Answer 1

This is a highly contagious respiratory infection caused by Bordetella pertussis

Aetiology

• Incubation period is 7-10 days
• Spread by aerosol droplets released during coughing
• Considered to be infectious from onset of symptoms until 48 hours of appropriate antibiotic treatment OR 21 days from onset of symptoms
• This is a NOTIFIABLE DISEASE- inform Public Healt

RFs: not vaccinated

Question 2

Symptoms and signs

Answer 2

Catarrhal phase: 1-2 weeks of coryza (nasal discharge, conjunctivitis, malaise, sore throat, low grade fever, dry, unproductive cough)

Paroxysmal phase: occurs 1 week after catarrhal phase and lasts between 1-6 weeks or up to 3 months of not vaccinated and first time contracting.

• The development of a characteristic paroxysmal or spasmodic cough followed by a characteristic inspiratory whoop (as short expiratory burst followed by inspiratory gasp)
• Spasms of cough are often worse at night and may cause vomiting
• IMPORTANT: in infants, apnoea may occur rather than whoop
• During the paroxysm, the child goes red or blue in the face (cyanosed) and may yield mucus plugs or watery secretions from the nose and mouth
• Can be triggered by external stimulus (e.g. cold or noise)
• Can be > 30 paroxysms in 24 hours
• NO signs on chest
• Nosebleeds (epistaxis) and subconjunctival haemorrhages can occur after vigorous coughing
• Post-tussive vomiting

Convalescent phase: lasts up to 3 months symptoms will eventually decrease and child recovers but may persist for many months.

NOTE: infants and young children suffering severe spasms of cough or cyanotic attacks should be admitted to hospital and isolated from other children

Question 3

Investigations

Answer 3

• Cardiorespiratory examination
• Basic observations (temp, RR, oxygen saturation, HR, BP - this doesn’t change until very acutely unwell in children)

1. Culture of a nasopharyngeal aspirate or nasopharyngeal/ pernasal swab
2. PCR of nasopharyngeal or throat swab- used to confirm infection if symptoms < 3 weeks
3. Anti-pertussis toxin IgG in oral fluid- if cough > 2 weeks (for those 5-16 years)

NOTE: vaccination can confound oral fluid tests

There is marked lymphocytosis on blood count

Question 4

Management

Answer 4

Admit (and isolate on ward) if <6mo or acutely unwell:

• Significant breathing difficulty (severe paroxysms, apnoea episodes, cyanosis)
• Significant complications (e.g. seizures, pneumonia)

Treatment (if admission is not needed, prescribe an antibiotic if the onset of the cough is within 21 days):

1st Line: MACROLIDE
* < 1 month old= clarithromycin
* ≥ 1 months/ non-pregnant adult= azithromycin
* Pregnant adult= erythromycin

Recommended from 36 weeks to reduce the risk of transmission to the newborn

• 2nd Line: Co-trimoxazole
• Used if macrolides are contraindicated or not tolerated
• (but not licensed for use in babies < 6 weeks old and contraindicated in pregnancy)

Advice:
* Rest, fluids, paracetamol or ibuprofen
* Educate parents – disease is likely to cause a protracted non-infectious cough (may take weeks to resolve fully); complete any outstanding immunisations; close contacts prophylaxis macrolides
* Avoid nursery until 48 hours of antibiotics or until 21 days after the onset of the cough if not treated
* Re-immunisation of mothers during pregnancy reduces the risk of pertussis in her infant during the first few months of life (this is when it can be particularly dangerous)
* Women who are between 16-32 weeks pregnant are offered the pertussis vaccine

Question 5

Complications/ Prognosis

Answer 5

Complications
* Apnoea
* Pneumonia
* Seizures
* Encephalopathy
* Otitis media
* Unilateral hearing loss
* Bronchiectasis
* Increased intrathoracic and intrabdominal pressure: pneumothorax, umbilical and inguinal hernias, rib fracture + disc herniation, subconjunctival/ scleral haemorrhage, facial and truncal petechiae
* Severe dehydration/ malnutrition from frequent post-tussive vomiting

Prognosis

Those not vaccinated and not contracted whooping cough before can have a protracted cough which may last for ≥ 3 months

Milder symptoms and shorter lived for those who have some immunity (i.e. vaccinated, or previously contracted)

Question 6

PACES

Answer 6

Explain the diagnosis (cough that lasts for a reasonably long time)

Explain that it isn’t seen very often because of the immunisation programme (and discuss concerns about immunisation with the parent)

Explain that having it once does not mean you can’t have it again

Explain that antibiotics can help treat the condition, but the cough often persists for a long time

Exclude from school until 48 hours after starting antibiotics