|

Whooping Cough (Pertussis)

Last updated:

Overview

Also known as pertussis, whooping cough is an infectious disease characterised by severe cough due to the bacterium Bordetella pertussis. Children and pregnant people are immunised against pertussis.

The incubation period is around 7-10 days and whooping cough is spread through respiratory secretions. Patients remain infectious for 21 days from the onset of symptoms if untreated.

Epidemiology

  • Before the introduction of immunisation, whooping cough was one of the most common childhood infections

Risk Factors

  • No vaccination
  • Close contact with infected individuals

Presentation

Phases

Whooping cough presents in 3 phases of symptoms:

  • Catarrhal phase – 1-2 weeks of features similar to an upper respiratory tract infection:
    • Rhinorrhoea
    • Malaise
    • Mild cough
    • Low-grade fever may be present
  • Paroxysmal phase – around 1 week of:
    • Paroxysmal (rapid, violent, and uncontrolled) coughing
    • An inspiratory ‘whoop’ – sharp inhalation of breath during coughing bouts
    • Post-tussive (post-coughing) vomiting
    • Infants may have apnoea
  • Convalescent phase – 2-3 weeks:
    • Gradual improvement in cough frequency and severity

Diagnosis

Whooping cough should be suspected if a person has had a cough for ≥14 days without an apparent cause and any one or more of the following:

  • Paroxysmal coughing
  • Inspiratory whoop
  • Post-tussive vomiting
  • Undiagnosed apnoeic attacks in young infants

Investigations

Overview

Some investigations may involve:

  • Nasopharyngeal/pernasal swab and culture:
    • May take days-weeks for results
  • Polymerase chain reaction (PCR):
    • Detects DNA of B. pertussis
  • Serology:
    • Detects antibodies to the whooping cough toxin

Management

Overview

General points:

  • Infants <6 months: admit to hospital
  • Notify Public Health England (PHE) – whooping cough is a notifiable disease
  • 1st-line: oral macrolide (clarithromycin, erythromycin, azithromycin) if within 21 days of the cough onset + offer household prophylaxis
    • This does not necessarily reduce the duration of the cough but reduces its spread
  • School exclusion:
    • For 48 hours after starting antibiotics
    • For 21 days from onset of symptoms if no antibiotics are given

Immunisation

  • Infants are routinely immunised at 2, 3, 4 months, and 5 years
  • People who are between 16-32 weeks pregnant are offered the vaccine. This is due to neonates being vulnerable to whooping cough.

Complications

Prognosis

  • Whooping cough in infants is associated with an increased risk of complications, hospitalisation, and death. Therefore, infants <6 months should be admitted to hospital
  • In older children and adults, the prognosis is generally good, but the cough may persist for months
  • Immunity from vaccination or natural disease wanes with time

Author