An unvaccinated 6-month-old infant is evaluated for a prolonged, severe cough. The pediatrician suspects an infection with Bordetella pertussis. This illness typically progresses through a very predictable sequence of distinct clinical phases. Arrange the following classic stages of a pertussis infection in the correct chronological order, from earliest (first) to latest (last).
- 1Incubation period (asymptomatic phase following initial respiratory droplet exposure)
- 2Catarrhal stage (mild coryza, sneezing, low-grade fever, and mild cough)
- 3Paroxysmal stage (episodes of severe, staccato coughing followed by an inspiratory whoop)
- 4Convalescent stage (gradual reduction in cough frequency and severity)
Answer
The correct sequence is: Incubation period, followed by the Catarrhal stage, then the Paroxysmal stage, and finally the Convalescent stage.
Bordetella pertussis infection follows a strict and highly characteristic temporal progression. Following initial exposure, there is an asymptomatic incubation period of 1 to 3 weeks. This is followed by the catarrhal stage (1-2 weeks) consisting of non-specific, mild upper respiratory symptoms (coryza, low-grade fever) which is also the most contagious period. The disease then progresses to the paroxysmal stage (2-6 weeks), featuring classic severe coughing spells, inspiratory whooping, and post-tussive emesis. Finally, the patient enters the convalescent stage, characterized by a gradual waning of the cough over several weeks to months.
Step-by-Step Solution
Key Concept
Clinical progression of Bordetella pertussis infection
Estimated Time:45s