Hello, my name is Ryan Coy, I'm a fourth-year resident at East Carolina University in Greenville, North Carolina. This is an extremely interesting case of an 80-year-old male with a history of multiple thoracic compression fractures with kyphoscoliosis who came in with about three months of dyspnea on standing and a severe significant functional decline. Every time the patient would lay down, his oxygen saturations would be perfect. In the 90s, he would be asymptomatic, but when he would stand up and try and ambulate, it would consistently drop down to the 60s for his oxygen saturation. No matter how much supplemental oxygen he was placed on, it would not significantly improve this phenomenon. We surmised that he had some sort of shunt going on, especially given that, you know, since oxygen wasn't helping, we thought that the right side circulatory system was going directly to the left side of his circulatory system without traversing the capillary beds in the lungs and undergoing gas exchange. But we had to think, how would this only happen transiently when he was standing up and not when he was laying down? On literature review, we were able to find this disorder, this syndrome called platypnea orthodioxia syndrome. And just as the name suggests, when the patient is in a spine position, they're okay, but when they're standing or sitting up, they have low oxygen levels. At first, we did an echo, transthoracic echo, and it showed nothing while the patient was supine, obviously. But then we said that we wanted to have the patient do the echo and also do a bubble study while they were sitting up, upright. When the sonographer did this, they were able to see a positive bubble study with bubbles traversing from the right side to the left side through the septal defect in the atrium. At that time, we diagnosed him with a patent foramen ovale, talked to cardiology. They were able to actually go in and fix his PFO, at which time he had complete resolution of his symptoms. We did some more literature review and found that only about 200 cases have been described since it was first described in 1949 of platypneo-orthodioxia syndrome. And actually, these patients, it comes on later on in life, oftentimes due to some sort of mechanical changes within the thorax. This can be explained as put forward by several papers. Sometimes when patients have compression fractures, when they are sitting upright and have gravity pulling down on their mediastinum and their heart and aortic arch, it can lengthen the heart tissue and two kind of flaps between the right atria and the left can come apart just slightly, leading to blood going from the right side to the left. The puzzling thing is, the pressures in the left atria are higher than in the right side. So several papers had talked about there being some sort of directional flow when blood comes through the inferior and superior vena cava, directs force locally more at that septal area, leading to local pressures being higher in that area, causing the right to left shunt. But no one really knows the exact way that this happens. So always think to yourself, if you have a patient that is desaturating when they're laying down, or when they're standing up I should say, but perfectly fine when they're laying down, they may have platypnea-orthodioxia syndrome. Thank you so much.

case study

dyspnea

platypnea-orthodeoxia syndrome

oxygen saturation

patent foramen ovale