Pertussis

Also called whooping cough, pertussis is a highly contagious infection caused by Bordetella pertussis. It characteristically produces an irritating cough that becomes paroxysmal and often ends in a high-pitched, inspiratory whoop.

About half the time it strikes under-immunized children under age 1. It also occurs in persons age 20 years or older and in outbreaks in schools, nursing homes, facilities, and residential facilities.

Since the 1940s, immunization and aggressive diagnosis and treatment have significantly reduced mortality from whooping cough in the United States. Pertussis mortality in children under age 1 usually is a result of insufficient immunization. Pertussis also is dangerous in elderly people but tends to be less severe in older children and adults.

Causes

Pertussis usually results from the nonmotile, gram-negative coccobacillus B. pertussis; occasionally, it's caused by the related similar bacteria B. parapertussis or B. bronchiseptica.

Pertussis usually is transmitted by direct inhalation of contaminated droplets from a patient in the acute stage. It also may be spread indirectly through soiled linen and other articles contaminated by respiratory secretions.

Signs and symptoms

• runny nose
• slight fever (102°F or lower)
• severe, repeated coughs that:
  • make breathing difficult
  • result in vomiting
  • produce a high-pitched "whooping" sound when a person takes a breath
  • cause a short loss of consciousness
• diarrhea
• choking spells in infants

Diagnostic tests

In addition to a complete medical history and physical examination, diagnosis of whooping cough is often confirmed with a culture taken from the nose.

Treatment

Infants and elderly patients usually require hospitalization and vigorous supportive therapy and fluid and electrolyte replacement. Other measures include adequate nutrition, oxygen therapy as warranted, and administration of antitussives and antibiotics, chiefly erythromycin, as ordered.

Prevention

The incidence and severity of pertussis is reduced by immunisation. The vaccine is usually given as a trivalent vaccine (DTP), in which pertussis is combined with diphtheria and tetanus vaccines. The primary course consists of 3 doses, the first at 2 months of age and then at intervals of 2 months. Booster doses are recommended at 18 months and at the time of school entry (4-5 years).

Experts believe that up to 80% of non-immunized family members will develop whooping cough if they live in the same house as someone who has the infection. For this reason, anyone who comes into close contact with a person who has pertussis should receive antibiotics to prevent spread of the disease. Young children who have not received all five doses of the vaccine may require a booster dose if exposed to an infected family member.