{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,12]],"date-time":"2026-01-12T18:43:46Z","timestamp":1768243426736,"version":"3.49.0"},"reference-count":25,"publisher":"BMJ","issue":"1","content-domain":{"domain":["bmj.com"],"crossmark-restriction":true},"short-container-title":["BMJ Case Rep"],"accepted":{"date-parts":[[2025,12,11]]},"published-print":{"date-parts":[[2026,1]]},"abstract":"<jats:p>Platypnoea\u2013orthodeoxia syndrome (POS) is a rare cause of posture-dependent hypoxaemia, usually linked to intracardiac right-to-left shunts. We report an elderly woman with progressive dyspnoea and recurrent falls whose oxygen saturation fell from 95% supine to 84% upright. Imaging showed kyphoscoliosis with partial right hemi-diaphragmatic dysfunction. Supine and upright contrast transthoracic echocardiography demonstrated delayed bubble appearance, excluding an intracardiac shunt and suggesting an intrapulmonary mechanism. CT pulmonary angiography and Tc-99m macroaggregated albumin scintigraphy ruled out pulmonary arteriovenous malformations, indicating posture-dependent ventilation\u2013perfusion mismatch as the cause. Comprehensive geriatric assessment identified frailty and limited physiological reserve, guiding conservative management with pulmonary rehabilitation and fall-prevention measures. This case emphasises the importance of postural pulse oximetry, sequential imaging and geriatric assessment in diagnosing POS in older adults and describes a rare extracardiac mechanism without cardiac or vascular shunting.<\/jats:p>","DOI":"10.1136\/bcr-2025-268870","type":"journal-article","created":{"date-parts":[[2026,1,12]],"date-time":"2026-01-12T15:30:48Z","timestamp":1768231848000},"page":"e268870","update-policy":"https:\/\/doi.org\/10.1136\/crossmarkpolicy","source":"Crossref","is-referenced-by-count":0,"title":["Platypnoea\u2013orthodeoxia from kyphoscoliosis and diaphragmatic dysfunction without intracardiac shunt on transthoracic echocardiography"],"prefix":"10.1136","volume":"19","author":[{"ORCID":"https:\/\/orcid.org\/0009-0002-6540-6100","authenticated-orcid":false,"given":"Venugopal","family":"Mantry","sequence":"first","affiliation":[{"name":"Department Of Geriatric Medicine, All India Institute Of Medical Sciences, New Delhi, Delhi, 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