A 19-month-old boy is brought to the physician by his parents for fever, running nose, and a sore throat. The GP reassures the parents and recommends supportive care with plenty of fluids. He sends them home with instructions to follow up if the boy’s symptoms worsen. Two days later, the infant is brought to the emergency department with persistent fever, brassy cough, and difficulty breathing. Physical examination reveals stridor. Which of the following pathogens is most likely responsible for this patient’s condition?
Ans. B. Parainfluenza
This child initially had fever, rhinitis, and pharyngitis, which are symptoms typical of an upper respiratory tract infection (URI}. When a child with a history of recent URI develops a brassy, barking cough and breathing difficulties, it is likely – that acute laryngotracheitis (croup) has developed. The dyspnea associated with croup occurs when inflamed subglottic tissue obstructs the upper airway. The characteristic stridor of the croup is a sign of significant upper airway obstruction. Croup is typically caused by the standard URI viruses, with the parainfluenza viruses (members of Paramyxoviridae) most commonly responsible.