Pertussis (Whooping Cough)

Pertussis is an acute respiratory infection caused by Bordetella pertussis. The bacterium produces toxins that contribute to the characteristic cough and interfere with respiratory defences. Transmission occurs through infectious respiratory particles and direct contact of susceptible mucous membranes with respiratory secretions. Symptoms in the initial catarrhal stage may begin 5–10 days after infection, but onset can occur as late as 21 days. This stage resembles an uncomplicated upper-respiratory infection, with rhinorrhea, low-grade fever, and a mild cough that progressively worsens. The paroxysmal stage brings repeated bursts of rapid, forceful coughing. A patient may make a high-pitched inspiratory whoop, vomit after coughing, or become exhausted while trying to recover. In the convalescent stage, recovery is gradual and the cough can persist for weeks to months. A persistent cough after antimicrobial therapy therefore does not, by itself, show treatment failure. The classic whoop is not required for recognition. Young infants can have an atypical presentation in which apnea is the main manifestation and the whoop or post-tussive vomiting is absent. Infants have the greatest risk of severe complications. Pneumonia, atelectasis, weight loss,...