Platypnoea-Orthodeoxia Syndrome: An Intriguing Diagnosis

Abstract

Platypnoea-orthodeoxia syndrome (POS) is an uncommon clinical entity characterized by dyspnoea and hypoxaemia induced by upright posture and relieved by recumbence. It is often associated with right-to-left shunting through a patent foramen ovale (PFO) or an atrial septal defect. We report the case of a 79-year-old woman with hypoxaemia initially attributed to a pulmonary infection but persisting after successful treatment. Being in the upright position triggered the hypoxaemia. A thoracic CT angiogram and ventilation/perfusion lung scan excluded a pulmonary embolism, but a transoesophageal echocardiogram with a bubble test showed a PFO with a right-to-left shunt, without pulmonary hypertension. The patient underwent percutaneous closure of the PFO which led to prompt symptom relief and full functional recovery.

Reversible platypnoea-orthodeoxia syndrome

“…Positional oxygen measurements done clinically would provide an estimate to the shunt magnitude. Cardiac catheterisation with direct measurement of oxygen saturation in the left atrium and pulmonary veins remains the gold standard for diagnosis of this syndrome associated with an intracardiac shunt 7. In our case, a patent foramen ovale of size 3.7 mm was found during the bubble contrast echocardiography.…”

“…This can be achieved by a surgical or percutaneous approach; the latter being preferred due to good results and reduced mortality and morbidity. However, not all patients need to undergo a definitive closure as this is usually determined by the functional component contributing to the shunt magnitude and patient disability 7. In our case, there was an unrecognised patent foramen ovale, which became a clinically significant shunt only when precipitated by a secondary correctible cause.…”

Transcranial Doppler Ultrasound and Transesophageal Echocardiography for Intraoperative Diagnosis and Monitoring of Patent Foramen Ovale in Non-Cardiac Surgery

“…Major surgery exposes patients with PFO to various factors that can cause RLS, including positive pressure mechanical ventilation, a severe reduction in systemic vascular resistance, clamping of great vessels, fluid therapy, anesthetic drugs, and patient positioning [3,4]. In addition to neurological complications, PFO can also cause hypoxemia and platypnea-orthodeoxia syndrome due to right-to-left shunting of deoxygenated blood [5].…”