A 4-year-old boy with untreated severe obstructive sleep apnea presents with poor weight gain, daytime somnolence, and abdominal distension. Examination shows elevated jugular venous pressure, loud second heart sound, and tender hepatomegaly. Which pathophysiological sequence best explains the hepatomegaly?

• A Chronic hypercapnia directly depressing hepatic protein synthesis
• B Recurrent aspiration pneumonitis causing pulmonary fibrosis and left heart failure
• C Obesity hypoventilation causing systemic hypertension and left ventricular failure
• D Chronic upper airway obstruction causing hypoxic pulmonary vasoconstriction, pulmonary hypertension, and right ventricular failure ✓

Explanation

Severe paediatric OSA causes repetitive nocturnal hypoxaemia and hypercapnia, driving hypoxic pulmonary vasoconstriction and eventually pulmonary hypertension with cor pulmonale. Right ventricular failure produces raised JVP, hepatomegaly, and failure to thrive. This end stage complication of OSA is classically described in children with adenotonsillar hypertrophy and resolves after adenotonsillectomy. Left-sided mechanisms do not fit the signs, which point to right heart failure.

Reference: Cummings Otolaryngology: Head and Neck Surgery, 7th ed.

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Written and medically reviewed by the StethoPrep medical team.