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What is Steeple sign is seen in and explain in detail?
Acute laryngotracheobronchitis or croup is a viral infection caused by parainfluenza type 1, 2, and sometimes 3. The critical area involved is subglottic larynx producing oedema with stridor and respiratory distress. X-ray (PA view) larynx shows typical "steeple sign" but X-rays are avoided as any manipulation may precipitate acute obstruction. Ref: PL Dhingra 7th edition of Ear, Nose and Throat; Pg no 328