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. 

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Aim

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

Definition

Pertussis (Whooping Cough) is a highly infectious respiratory illness caused by Bordatella pertussis.

Background

  • Despite immunisation, pertussis epidemics occur every 3-4 years
  • Neonates and young infants are at risk of apnoea
  • Antibiotic treatment does not shorten the duration of illness but reduces infectivity
  • Cough may last for 3 months (100 day cough).
  • Immunised children may have a milder illness.

Incubation period

  • 7-21 days

Infectious period

  • Patients are infectious from the initial catarrhal period to 3 weeks after onset of cough.They are considered non infectious after completion of a 5 day course of antibiotics.

Isolation

  • Isolate suspected cases of pertussis 
  • Droplet precautions 
  • Patients are infectious until they have completed 5 days of antibiotics or >21 days of paroxysmal cough.

Immunity

  • Natural infection does not confer lifelong immunity
  • Immunity after infection or immunisation decreases after 5 years
  • The current Australian National Immunisation Schedule recommends acellular pertussis vaccine at 2, 4 and 6 months, 4 years and 10-15 years.

Complications

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

Risk factors

  • Infants less than 6 months of age
  • Unimmunised patients.

Assessment

  • Paroxysmal cough followed by inspiratory whoop is the classical presentation
  • Young infants may not have characteristic inspiratory whoop.

History

  • Ask for immunisation history.
  • Pertussis usually starts with mild coryza and low grade fever for 2-6 days (catarrhal stage) and is difficult to differentiate from viral 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
  • Infants younger than 6 months are at risk of apnoea.

Examination

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

Investigations

  • Nasopharyngeal aspirate or pernasal swab for pertussis PCR, IgA and culture.

Differential diagnoses

  • Bronchiolitis
  • Mycolasma pneumonia
  • Chlamydia pneumonia.

Management

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

Initial management

  • Oxygen for hypoxia
  • Respiratory support for apnoea – involve PICU early.

Medications

  • Antibiotic therapy reduces infectivity but not 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 only necessary for high risk contacts of pertussis cases:
    • any woman in the last month of pregnancy regardless of immunisation status
    • close household contacts of any child <24 months age who have not received 3 doses of pertussis vaccine.

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.

Bibliography

  1. AMH Children’s Dosing Companion (2015) Australian Medicines Handbook Pty Ltd
  2. Textbook of Pediatric Emergency Medicine. 6th ed. Fleisher GR, Ludwig S. Philadelphia: Lippincott Williams & Wilkins, 2010.
  3. Textbook of Paediatric Emergency Medicine 2nd Edition Cameron Elesevier 2012
  4. Robert M. Kliegman, Bonita M.D. Stanton, Joseph St. Geme, Nina F Schor, Nelson. Textbook of Pediatrics: 20th Edition Publisher: Elsevier


Endorsed by:  Emergency Department Guidelines team  Date:  May 2018


 Review date:   May 2021


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