A nurse in the emergency department is assessing a 4-month-old infant who has suspected pertussis. Which of the following findings should the nurse identify as consistent with this diagnosis? (Select all that apply.)

A. Dry, hacking cough that worsens at night is incorrect because this presentation is more characteristic of viral upper respiratory infections or asthma. Pertussis cough is not typically dry and hacking; it is paroxysmal, meaning sudden, forceful coughing spells. B. Wheezing with shortness of breath during activity is incorrect because this finding is more consistent with asthma or bronchiolitis. Pertussis primarily causes severe coughing fits, not wheezing related to exertion. C. Inspiratory stridor with a barking cough is incorrect because this describes croup (laryngotracheobronchitis). Croup is associated with stridor and a seal-like barking cough, not the classic cough pattern of pertussis. D. Paroxysmal coughing followed by a high-pitched “whoop” on inspiration is correct because this is the classic hallmark of pertussis (whooping cough). The repeated coughing exhausts the patient, and the forceful inspiration that follows produces the characteristic “whoop,” especially in infants and young children. E. Apnea and cyanosis during coughing episodes is correct because infants with pertussis may experience periods of apnea, hypoxia, and cyanosis during severe coughing spells. This is particularly dangerous in young infants and is a key reason pertussis can be life-threatening in this age group.