Platypnoea-Orthodeoxia Syndrome: An Intriguing Diagnosis

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.

Platypnoea-orthodeoxia syndrome is an uncommon condition that should be suspected in the presence of unexplained positional hypoxaemia.A high level of suspicion is required and the diagnosis can be safely established by tilt-table transoesophageal echocardiography.Percutaneous closure of a patent foramen ovale is safe and effective even in elderly patients.