What is the most common cause of obstructive sleep apnea in children?

Correct answer: A. Adenotonsillar hypertrophy

• A. CORRECT. ADENOTONSILLAR HYPERTROPHY is by far the leading cause of paediatric OSA. Lymphoid tissue peaks in size between ages 3 and 8, precisely when paediatric OSA peaks, and adenotonsillectomy is the first-line treatment. Obesity is the second major contributor and is rising in importance.
• B. Septal deviation contributes to nasal obstruction and mouth breathing but is rarely the primary driver of paediatric OSA.
• C. UNDERdeveloped adenoids would enlarge the airway, not obstruct it — this is the opposite of the mechanism.
• D. Macroglossia causes OSA in specific syndromes (Down syndrome, Beckwith-Wiedemann) but is uncommon as an isolated cause in the general paediatric population.

Note: Dental signs suggesting paediatric OSA: chronic mouth breathing, a long adenoid facies, a narrow high-arched palate with posterior crossbite, and bruxism. Screen for snoring and daytime behavioural problems, and refer for polysomnography.