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Key Features

Essentials of Diagnosis

  • Predominantly occurs in infants under age 2 years

  • Adolescents and adults are reservoir of infection

  • Two-week prodromal catarrhal stage of malaise, cough, coryza, and anorexia

  • Paroxysmal cough ending in a high-pitched inspiratory "whoop"

  • Absolute lymphocytosis, often striking; nasopharyngeal culture confirms diagnosis

General Considerations

  • An acute infection of the respiratory tract caused by Bordetella pertussis, a gram-negative coccobacillus

  • Infection is transmitted by respiratory droplets

  • Neither immunization nor disease confers lasting immunity to pertussis

  • The diagnosis often is not considered in adults, who may not have a typical presentation; cough persisting more than 2 weeks is suggestive of pertussis

Demographics

  • Pertussis causes high morbidity and mortality in many countries

  • Incidence of pertussis has increased steadily since the 1980s

Clinical Findings

Symptoms and Signs

  • Symptoms of classic pertussis last about 6 weeks and are divided into three consecutive stages

  • The catarrhal stage

    • Characterized by its insidious onset

    • Lacrimation, sneezing, and coryza, anorexia, and malaise

    • Hacking night cough that tends to become diurnal

  • The paroxysmal stage

    • Characterized by bursts of rapid, consecutive coughs followed by a deep, high-pitched inspiration (whoop)

  • The convalescent stage

    • Usually begins 4 weeks after onset of the illness with a decrease in the frequency and severity of paroxysms of cough

Differential Diagnosis

  • Viral or bacterial pneumonia

  • Asthma

  • Other causes of chronic cough in adults

    • Postnasal drip

    • Gastroesophageal reflux disease

    • Tuberculosis

    • Mycobacterium avium complex

  • Bronchiolitis, eg, respiratory syncytial virus (children)

  • Croup (children)

Diagnosis

  • The white blood cell count is usually 15,000–20,000/mcL (rarely, as high as 50,000/mcL or more), 60–80% of which are lymphocytes

  • The organism can be cultured from the nasopharynx using a special medium (eg, Bordet-Gengou agar)

Treatment

  • Erythromycin, 500 mg four times daily orally for 7 days

  • Azithromycin, 500 mg once daily orally for 1 day, then 250 mg once daily for 4 days

  • Clarithromycin, 500 mg three times daily for 7 days

  • Trimethoprim-sulfamethoxazole 160 mg–800 mg orally twice a day for 7 days

  • Treatment shortens the duration of carriage and may diminish the severity of coughing paroxysms

Outcome

Prevention

  • Immunizations (Table 30–7)

  • Acellular pertussis vaccine is recommended for all infants, combined with diphtheria and tetanus toxoids (DTaP)

  • Infants and susceptible adults with significant exposure should receive prophylaxis with an oral macrolide

  • Adults of all ages (including those > 64 years) should receive a single dose of Tdap

  • Pregnant women

    • Should receive a dose of Tdap during each pregnancy regardless of prior vaccination history, ideally between 27 and 36 weeks of gestation to maximize the antibody response of the ...

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