'Steeple sign' on X-ray is seen in?

Ans. A. Acute laryngotracheobronchitisCROUPa. Croup (acute laryngotracheobronchitis), represents the most common cause of upper airway obstruction in children.b. It is most commonly seen in the 6-month-to-3-year age group.c. The principal infectious organisms in croup include parainfluenza virus and respiratory syncytial virus.d. Patients present with a barky cough and stridor.e. The classic finding on a frontal radiograph is a tapered narrowing of the trachea in the subglottic region, producing a "V" configuration of airway narrowing (The 'steeple sign').f. The 'steeple sign' is produced by the presence of edema in the trachea in Croup, which results in elevation of the tracheal mucosa and loss of the normal shouldering (lateral convexities) of the air column.g. It is seen on anteroposterior radiographs of the soft tissues of the neck.h. The narrowing of the subglottic lumen alters the radiographic appearance of the tracheal air column, which resembles a steeply pitched roof or a church steeple.