Pertussis

Disclaimer These guidelines have been produced to guide clinical decision making for the medical, nursing and allied health staff of Perth Children’s Hospital. They are not strict protocols, and they do not replace the judgement of a senior clinician. Clinical common sense should be applied at all times. These clinical guidelines should never be relied on as a substitute for proper assessment with respect to the particular circumstances of each case and the needs of each patient. Clinicians should also consider the local skill level available and their local area policies before following any guideline.  Read the full CAHS clinical disclaimer

Aim

To guide PCH Emergency Department (ED) staff with the assessment and management of pertussis in children who present to the ED.

Definition

Pertussis (Whooping Cough) is a highly infectious respiratory illness caused by the bacterium Bordetella pertussis.

Background⁵

• Despite immunisation, pertussis epidemics occur every 3-4 years.
• The clinical presentation of pertussis varies by age. Classic pertussis is characterised by a catarrhal phase (coryza and cough) that is followed 1-2 weeks later by the development of a paroxysmal cough.
• Neonates and young infants may present with non-specific signs and are at risk of apnoea.
• Antibiotic treatment may not shorten the duration of illness but reduces infectivity.
• Immunised children and adults may have a milder illness.

Incubation period

• 4-21 days, usually 7 to 10 days.⁵

Infectious period

• Patients are infectious from the onset of initial catarrhal period to 3 weeks after onset of cough. They are considered non-infectious after completion of 5 days of an appropriate antibiotic.⁵

Infection prevention and control

• Isolate suspected cases of pertussis on presentation to hospital.
  • Patients should preferably be allocated to a single room with contact and droplet transmission-based precautions in place.
• Refer to the CAHS Transmissible Diseases Index for further information (internal WA Health only).

Immunity

• Natural infection does not confer lifelong immunity
• Immunity after infection or immunisation decreases after 5 years
• The current Australian National Immunisation Program Schedule recommends acellular pertussis vaccine at 2, 4, 6 and 18 months, 4 years and 12-13 years.⁹

Complications

• Complications include pertussis pneumonia, seizures, hypoxic encephalopathy and death.

Risk factors

• Infants less than 6 months of age
• Unimmunised patients 

History

• Check the Australian Immunisation Register (AIR) record for the child’s immunisation history and for infants < 6 months of age ask maternal pregnancy immunisation history.
• Pertussis usually starts with mild coryza and mild cough, fever is uncommon and if present, usually low grade for 2-6 days (catarrhal stage) and is difficult to differentiate from viral upper respiratory tract infection (URTI).
• Cattarhal stage develops into a dry, non-productive paroxysmal cough which may be associated with cyanosis.
• The cough is often worse at night.
• Inspiratory 'whoop' may or may not be present.
• Post-tussive vomiting is common in children.
• Neonates and young infants may present with non-specific signs and are at risk of apnoea, severe pneumonia (associated with extreme leucocytosis > 60,000 cell/mL), pulmonary hypertension, seizures and encephalopathy.

Examination

• Most patients will not have clinical signs of lower respiratory tract infection (LRTI).
• Conjunctival haemorrhage or facial petechiae may be present from forceful coughing.
• Assess for hypoxia
• Young infants may be exhausted after coughing paroxysms.

Investigations

• If less than 3 weeks since symptom onset - Pertussis PCR
  • Can be performed on a nasopharyngeal swab (preferred), nasopharyngeal aspirate or sputum sample.
    Note: pertussis is included in the BioFire^® respiratory panel at PathWest QEII, however, it has lower sensitivity compared to targeted pertussis PCR. If pertussis is suspected, request pertussis PCR in addition to BioFire^® respiratory PCR. Can use same sample to run both the BioFire^® respiratory panel and dedicated pertussis PCR. 
• If more than 3 weeks since symptom onset - Pertussis serology.
  • Quantitative pertussis toxin IgG performed on patient serum.

Differential diagnoses

• Bronchiolitis (other respiratory viral pathogens)
• Mycoplasma pneumoniae infection
• Chlamydophila pneumoniae infection
• Sometimes infection with Bordetella parapertussis can present in a similar way. If detected in a symptomatic patient, it should be treated in the same way as for pertussis.

Management

• Patients with cyanosis or apnoea should be admitted for antibiotics and observation.
• Non-admitted patients with suspected pertussis should be isolated from childcare, school and health care settings until 5 days of antibiotic therapy has been completed.

Initial management

• Oxygen for hypoxia
• Respiratory support for apnoea – involve Paediatric Critical Care early.

Medications

• Antibiotic therapy reduces infectivity but not the duration of symptoms.
• Antibiotic treatment is not recommended if the duration of the paroxysmal cough is >21 days.
• Antibiotic therapy is guided by the Children's Antimicrobial Management Program (ChAMP) - Acute Respiratory Tract Infection.
• Antibiotic prophylaxis is recommended for high risk contacts of pertussis cases⁵
  • Refer to Medical Prophylaxis  guideline – ChAMP
  • Expectant parents (or carers) in the last month of pregnancy regardless of immunisation status
  • All household members where there is an infant < 6 months present
  • Adults and children who have contact with infants < 6 months (e.g., in a childcare setting)
• Prophylactic antibiotic regimens are the same as for the treatment of pertussis. Refer to Medical Prophylaxis – ChAMP.

Admission criteria

• Have a low threshold for admitting young infants <3 months with suspected pertussis for observation.

Referrals and follow-up

• All confirmed cases of pertussis must be reported to public health.
• Pertussis is a notifiable disease. Refer to Pertussis (Whooping Cough) Statutory notification alert for information on reporting.⁸

References

1. AMH Children’s Dosing Companion (2022) Australian Medicines Handbook Pty Ltd 2022. Available from: AMH Children's Dosing Companion (health.wa.gov.au)
2. Fleisher and Ludwig's Textbook of Pediatric Emergency Medicine Eighth Edition. Journal of Pediatric Critical Care 8.2 (2021): 116. Web. Kundan Mittal.
3. Textbook of Paediatric Emergency Medicine. 3rd ed. Cameron P, Browne GJ, Mitra B, et al (2018) Publisher: Elsevier Edition updated
4. Nelson Textbook of Pediatrics: 21st Edition Robert M. Kliegman, St Geme JW, Blum MJ et al. 2020 Publisher: Elsevier
5. Communicable Diseases Network of Australia. Pertussis: CDNA National Guidelines for Public Health Units, version 3.0. Commonwealth Department of Health, 2015. Available from: https://www.health.gov.au/resources/publications/pertussis-whooping-cough-cdna-national-guidelines-for-public-health-units
6. Antibiotic Writing Group. Therapeutic Guidelines - Antibiotic. West Melbourne: Therapeutic Guidelines Ltd; 2022. Available from: https://tgldcdp-tg-org-au.pklibresources.health.wa.gov.au/etgAccess
7. Australian Immunisation Handbook 10^th Edition. Department of Health and National Health Medical Research Council, Canberra, 2013 (updated 2018). Available from: https://immunisationhandbook.health.gov.au/  
8. Pertussis (Whooping Cough) Statutory notification alert. Government of Western Australia, Department of Health [Internet, Cited: 12 July 2023]
9. National Immunisation Program Schedule (health.gov.au). Australian Government Department of Health and Aged Care. [Internet, Cited: 12 July 2023]

Endorsed by:	Nurse, Co-director, Surgical Services	Date:	Oct 2023
		Review date:	Sep 2026

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