Platypnea-Orthodeoxia Syndrome in Relation to Severe SARS-CoV-2 Infection

Platypnea-orthodeoxia syndrome (POS) is characterized by dyspnea and oxygen desaturation in the upright position, caused by arteriovenous shunts (intracardiac, intrapulmonary, or physiological). In recent years, POS has been described in patients with SARS-CoV-2 infection, in both acute and rehabilitation phases. This case describes a 90-year-old man who presented to the emergency department with a dry cough and dyspnea and was diagnosed with severe SARS-CoV-2 infection. He underwent non-invasive ventilation for refractory hypoxemia. During convalescence, CT scans revealed fibrotic changes predominantly in the lung bases. He experienced persistent dyspnea and oxygen desaturation upon standing. Blood gas analysis confirmed orthodeoxia. After ruling out intracardiac and intrapulmonary shunts, secondary POS due to SARS-CoV-2 infection was presumed. He continued rehabilitation with progressive improvement, resolving the condition a month after discharge. This phenomenon, likely induced by fibrotic sequelae of SARS-CoV-2 in the lung bases causing a physiological shunt, highlights a potentially underdiagnosed complication of interstitial lung diseases.