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OSA as Secondary Hypertension Cause — EECC MCQ

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ModerateHypertension & Preventive CardiologyOSA as Secondary Hypertension CauseEECC

A 50-year-old woman with resistant hypertension has a 24-hour ABPM showing nocturnal BP of 155/95 mmHg with a reverse dipping pattern (night > day). She snores and has an Epworth Sleepiness Score of 14. What is the most likely secondary cause?

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Correct answer: A — Obstructive sleep apnoea (OSA) — the most common secondary cause of resistant hypertension; OSA causes nocturnal hypertension and reverse dipping through intermittent hypoxia, sympathetic activation, and endothelial dysfunction

OSA is the most common secondary cause of resistant hypertension (prevalence 60-80% in resistant HTN cohorts). Mechanisms linking OSA to hypertension: (1) intermittent hypoxia → sympathetic activation → sustained daytime hypertension; (2) intrathoracic pressure swings → increased LV afterload; (3) endothelial dysfunction; (4) RAAS activation; (5) inflammation/oxidative stress. OSA characteristically causes: non-dipping or reverse-dipping nocturnal BP pattern (nocturnal hypoxia drives nocturnal sympathetic surges). The 2024 ESC Hypertension Guidelines recommend screening for OSA in: resistant hypertension, non-dipping/reverse-dipping pattern, obesity, excessive daytime sleepiness. Treatment: CPAP improves nocturnal BP by ~2-4 mmHg and may improve overall BP control. The AF-CARE pathway also includes OSA management as comorbidity management for AF.

Reference: ESC (2024): Hypertension Guidelines