Introduction: Platypnea-Orthodeoxia syndrome is caused by intra-cardiac, pulmomary arteriovenous or pulmonary parenchymal shunt. It‘s first clinical manifestation in an elderly lady as a result of ‘unmasking‘ of a patent foramen ovale (PFO) attributable to her worsening kypho-scoliosis is a novel and poorly understood presentation.
Case Summary: An 85 year old lady presented with breathlessness and hypoxia (PaO25.6kPa, PaCO25.2kPa, pH7.4).Clinical examination was normal apart from marked kypho-scoliosis. Her ECG, chest X-ray, High resolution chest CT, CT pulmonary Angiogram, Ventilation/Perfusion scans and Trans-thoracic ECHO were all within normal limits. In particular, she had normal pulmonary pressures. Her lung functions demonstrated a restrictive defect with a normal single-breath diffusion capacity of carbon monoxide. She subsequently exhibited orthodeoxia prompting a ‘bubble‘ ECHO study. This revealed a large PFO with a prominent ‘right to left‘ shunt, confirmed on Trans-oesophageal ECHO. Percutaneous transcathetar closure of the PFO returned her oxygen saturation to within normal limits enabling rehabilitation.
Discussion: Symptomatic Platpynea-Orthodeoxia syndrome without pulmonary hypertension can be caused by altered intra-thoracic anatomy and physiology. It is postulated that kyphoscoliosis resulting in right atrial compression and alteration to caval flow may result in ‘right to left‘ shunt unmasking a ‘silent‘ PFO. PFO‘s, occurring in 10-20% of adults, are largely asymptomatic. However, with a growing geriatric population and increasing incidence of spinal deformities such curable possibilities must be included in differentials of otherwise unexplained hypoxia.