Pertussis

Pertussis, commonly known as whooping cough, is a highly contagious respiratory infection caused by the bacterium Bordetella pertussis. It is characterized by severe coughing fits followed by a “whooping” sound when the person breathes in, especially in children.

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Causes

Pertussis is caused by the bacterium Bordetella pertussis, which attaches to the lining of the upper respiratory tract and produces toxins that:

1. Damage the respiratory epithelium.
2. Cause inflammation and interfere with the clearance of mucus.

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Transmission

• Mode of Spread: Person-to-person via respiratory droplets when an infected person coughs or sneezes.
• Infectious Period: Most contagious during the early stage (first 2 weeks) when symptoms resemble a common cold.

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Symptoms

Pertussis develops in three stages:

1. Catarrhal Stage (1–2 weeks):
   • Symptoms mimic a cold:
     • Runny nose
     • Mild cough
     • Low-grade fever
     • Sneezing
   • Highly contagious during this stage.
2. Paroxysmal Stage (2–6 weeks):
   • Severe, forceful coughing fits (paroxysms) followed by a “whooping” sound when inhaling.
   • Post-cough vomiting or exhaustion.
   • Mucus production increases.
   • Cyanosis (bluish skin) or difficulty breathing in severe cases.
3. Convalescent Stage (weeks to months):
   • Gradual recovery with decreased coughing frequency.
   • Persistent mild cough may linger for weeks.

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Complications

Pertussis can lead to serious complications, especially in infants under 6 months:

• In Infants:
  • Apnea (temporary cessation of breathing)
  • Pneumonia
  • Seizures
  • Brain damage (from lack of oxygen)
  • Death in severe cases
• In Older Children/Adults:
  • Rib fractures from severe coughing
  • Urinary incontinence
  • Secondary infections

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Diagnosis

• Clinical Symptoms: Severe coughing fits with a characteristic whooping sound.
• Diagnostic Tests:
  • Nasal/throat swab culture to detect Bordetella pertussis.
  • PCR testing (rapid and accurate).
  • Blood tests for elevated white blood cell counts (indicative of infection).

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Treatment

1. Antibiotics:
   • Macrolides (e.g., azithromycin, erythromycin) are effective if started early in the illness.
   • Antibiotics help reduce transmission but may not alleviate symptoms in the later stages.
2. Supportive Care:
   • Adequate hydration.
   • Small, frequent meals to prevent post-cough vomiting.
   • Avoid irritants like smoke or strong odors.
   • In severe cases (especially in infants), hospitalization may be required for:
     • Oxygen therapy
     • Monitoring for apnea or dehydration

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Prevention

1. Vaccination:
   • DTaP vaccine (for children under 7 years): Protects against diphtheria, tetanus, and pertussis.
   • Tdap booster (for adolescents and adults): Recommended during each pregnancy to protect newborns.
   • Vaccination provides strong, but not lifelong, immunity; boosters are needed.
2. Hygiene Measures:
   • Covering mouth/nose when coughing or sneezing.
   • Frequent handwashing.
   • Avoid close contact with infected individuals.
3. Post-Exposure Prophylaxis:
   • Close contacts of pertussis cases may be prescribed antibiotics to prevent infection, particularly in high-risk groups (e.g., infants, pregnant women).

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Prognosis

• With timely treatment, most individuals recover fully.
• Severe complications are more common in infants, emphasizing the importance of prevention and vaccination.

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Key Points

• Pertussis is preventable through vaccination.
• Early diagnosis and treatment are critical to reducing the severity of symptoms and preventing transmission.
• Infants and unvaccinated individuals are at the highest risk of severe complications.