Tag Archives: platypnea-orthodeoxia syndrome

Introduction Platypnea-orthodeoxia syndrome (POS) is a rare condition, the prevalence of which has yet to be estimated in the literature.1 It presents with positional dyspnoea and deoxygenation on an orthopneic position which resolves when the patient moves to a supine position. Diagnosis is often challenging and this syndrome is thought to be under-recognised.2 Its mechanisms are not fully understood but these can be classified into extracardiac and intracardiac causes. Extracardiac causes include pathology leading to intrapulmonary shunting or ventilation-perfusion mismatch, such as pulmonary arteriovenous malformations or severe intestinal