Unexplained Positional Hypoxemia in an Elderly Patient: A Case of Platypnea-Orthodeoxia Syndrome.

Patent foramen ovale is a congenital cardiac condition that may remain clinically silent until advanced age. One of its potential manifestations is platypnea-orthodeoxia syndrome, characterized by hypoxemia in the upright position with improvement in the supine position. Diagnosis may be delayed and challenging in older adults, as hypoxemia is frequently attributed to alternative conditions such as infection, pulmonary disease, or age-related physiological changes. We report the case of an 88-year-old man admitted with suspected urosepsis in whom refractory hypoxemia of unclear origin was documented despite unremarkable pulmonary and initial cardiac imaging studies. Marked oxygen desaturation occurred when seated or standing and resolved in the supine position. Two-dimensional transesophageal echocardiography with bubble study confirmed the presence of a patent foramen ovale with right-to-left shunting. Percutaneous closure was successfully performed, resulting in complete resolution of hypoxemia. Notably, the patient also experienced a reduction in the frequency and intensity of migraine episodes following the intervention. To our knowledge, reports of symptomatic platypnea-orthodeoxia syndrome requiring percutaneous closure in patients of such advanced age remain limited. This case emphasizes the importance of considering intracardiac shunting in older patients with unexplained positional hypoxemia and supports the role of individualized decision-making regarding patent foramen ovale closure to preserve functional status in selected elderly individuals.