Which finding is most significant for pertussis in an adolescent patient?

Which finding is most significant for pertussis in an adolescent patient?

• A. Hyperinflation on chest x-ray
• B. Persistent night-time cough
• C. Lymphocytosis on CBC
• D. Productive cough

Answer: (D)

In pertussis, a hallmark clue in adolescents is a marked lymphocytosis on CBC. This rise in lymphocytes is driven by the Bordetella pertussis infection and its toxins, and it tends to be more specific for pertussis than other common respiratory illnesses that cause a long cough. While a chest x-ray may show hyperinflation and a persistent night-time cough can occur with many conditions, these findings are nonspecific. A productive cough, on the other hand, is not typical of pertussis, where the cough is usually paroxysmal with little sputum. For these reasons, the lymphocytosis on CBC is the most significant indicator among the options.

In pertussis, a hallmark clue in adolescents is a marked lymphocytosis on CBC. This rise in lymphocytes is driven by the Bordetella pertussis infection and its toxins, and it tends to be more specific for pertussis than other common respiratory illnesses that cause a long cough. While a chest x-ray may show hyperinflation and a persistent night-time cough can occur with many conditions, these findings are nonspecific. A productive cough, on the other hand, is not typical of pertussis, where the cough is usually paroxysmal with little sputum. For these reasons, the lymphocytosis on CBC is the most significant indicator among the options.