Whooping Cough (Pertussis)

Definition | Aetiology | Pathophysiology | Risk Factors | Signs and Symptoms | Investigations | Management | References

Definition

Whooping cough, also known as pertussis, is a highly contagious respiratory tract infection caused by the bacterium Bordetella pertussis. It is characterised by severe coughing fits followed by a high-pitched "whoop" sound during the next breath.

Aetiology

Whooping cough is caused by Bordetella pertussis, a Gram-negative coccobacillus bacterium. The bacterium produces toxins that damage the respiratory epithelium and disrupt the immune response.

Pathophysiology

The pathophysiology of whooping cough involves:

• Bordetella pertussis attaches to the cilia of the respiratory epithelial cells.
• The bacteria release toxins that paralyse the cilia, causing inflammation and interfering with the clearance of pulmonary secretions.
• This results in the characteristic severe coughing fits and the "whooping" sound as the patient breathes in deeply after a coughing spell.

Risk Factors

• Unvaccinated individuals, particularly infants and children
• Close contact with an infected person
• Living in crowded conditions
• Weakened immune system
• Incomplete vaccination schedule

Signs and Symptoms

Whooping cough typically progresses through three stages:

• Catarrhal Stage: Mild symptoms similar to the common cold, including runny nose, mild cough, and low-grade fever. This stage lasts 1-2 weeks.
• Paroxysmal Stage: Severe coughing fits followed by the characteristic "whoop" sound. The cough may be followed by vomiting or exhaustion. This stage lasts 1-6 weeks.
• Convalescent Stage: Gradual recovery with a reduction in coughing fits, but coughing may persist for weeks or months.

Investigations

Specific investigations to diagnose whooping cough include:

• Nasal or throat swab: Culture and PCR testing to detect Bordetella pertussis.
• Serology: Detection of specific antibodies against Bordetella pertussis.
• Full blood count (FBC): Often shows a marked lymphocytosis.

Management

Primary Care Management

• Antibiotics: Macrolides (e.g., clarithromycin) to reduce the severity and duration of symptoms and prevent transmission.
• Supportive care: Ensuring adequate hydration, rest, and managing symptoms such as fever and cough.
• Isolation: Preventing the spread of infection to others, especially vulnerable populations like infants.

Specialist Management

• Hospitalisation: For severe cases, particularly in infants and young children who may require supportive measures such as oxygen therapy or mechanical ventilation.
• Management of complications: Treating secondary infections like pneumonia, or complications like seizures and encephalopathy.
• Referral to specialists: In cases of severe or complicated infections, referral to paediatricians or infectious disease specialists may be necessary.

Vaccination

The primary prevention strategy for whooping cough is vaccination. The pertussis vaccine is part of the 6-in-1 vaccine (diphtheria, tetanus, hepatitis B, polio, whooping cough) given to babies at 8, 12, and 16 weeks of age.

References

1. NHS (2024) Whooping cough (pertussis). Available at: https://www.nhs.uk/conditions/whooping-cough/ (Accessed: 24 June 2024).
2. Centers for Disease Control and Prevention (2024) Pertussis (Whooping Cough). Available at: https://www.cdc.gov/pertussis/index.html (Accessed: 24 June 2024).
3. World Health Organization (2024) Pertussis. Available at: https://www.who.int/news-room/fact-sheets/detail/pertussis (Accessed: 24 June 2024).

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