This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Larynx, Subject name: ENT
Steeple sign seen on posteroanterior view of neck in a child with stridor is indicative of: 
Select and explain. 
A. Acute epiglottitis, B. Acute laryngotracheobronchitis, C. Laryngeal papillomatosis, D. Bilateral abductor paralysis
B: Acute laryngotracheobronchitis
Answer: B: Acute laryngotracheobronchitis 
Explanation: Steeple sign indicates narrowing of the airway in the subglottic area. It is typically seen in acute laryngotracheobronchitis in children.Thumb sign is typically seen in acute epiglottitis due to swollen epiglottis. It is better appreciated in lateral view of neck.Steeple sign (like a church tower) is seen in laryngotracheobronchitis (croup) in PA view of neck. Note the air shadow (arrow).