A child presents with snoring, mouth breathing and daytime sleepiness. What is the MOST common underlying cause of obstructive sleep apnoea in children?

Correct answer: D. Adenotonsillar hypertrophy

• A. Macroglossia causes OSA in specific syndromes (Down syndrome, Beckwith-Wiedemann) but is not the general cause.
• B. Obesity is the leading cause in ADULTS and is increasingly relevant in children, but it is not the most common paediatric cause.
• C. Mandibular retrognathia contributes in certain craniofacial syndromes but is not the commonest cause.
• D. Correct. ADENOTONSILLAR HYPERTROPHY is the commonest cause of paediatric OSA, and ADENOTONSILLECTOMY is the first-line treatment. The dental relevance is substantial: chronic nasal obstruction forces mouth breathing, which produces the classic ADENOID FACIES — a long lower facial height, narrow high-arched palate, posterior crossbite, incompetent lips and anterior open bite. Dentists are often the first to recognise the pattern and refer to ENT.