An Older Woman With Refractory Hypoxemia

Key TakeawaysThis case highlights platypnea-orthodeoxia syndrome as an uncommon but important cause of unexplained dyspnea and hypoxemia, particularly in patients whose oxygen levels worsen when upright and improve poorly with supplemental oxygen. In this patient, the condition was ultimately traced to a patent foramen ovale causing a significant right-to-left shunt, which was confirmed by transesophageal echocardiography and treated with endovascular closure. The case emphasizes the need to consider intracardiac shunting in the differential diagnosis of persistent, unexplained hypoxia.The case report by internist Shaun A. Hanycz, MD, and colleagues at Western University in London, Ontario, Canada, documents a rare clinical presentation.The Patient and Her Medical HistoryAn 86-year-old woman presented to the emergency department of a hospital in London with chronic dyspnea that had been progressively worsening for 1 week, as well as acute confusion.Her preexisting conditions included obstructive lung disease, paroxysmal atrial fibrillation, arterial hypertension, bronchial asthma, obstructive sleep apnea, spinal stenosis, kyphosis, osteoporosis, gastroesophageal reflux disease, dyslipidemia, previous ischemic cerebellar infarcts, and hypothyroidism.The patient was taking the following medications on a regular basis: apixaban, bisoprolol, ezetimibe, levothyroxine, budesonide-formoterol, and rosuvastatin.Her family, social, substance use, travel, and allergy histories were unremarkable.FindingsUpon admission, the patient’s vital signs were measured. Her heart rate was 88 beats/min. Blood pressure was 149/107 mm Hg. Respiratory rate was 22 breaths/min. Oxygen saturation, with 2 L of oxygen administration, was 93%. Body temperature was within normal limits.The physical examination revealed a systolic murmur over the left sternal border. There was no leg edema or jugular venous distension. Breath sounds were vesicular.Laboratory tests showed leukocytosis at 19.3 × 109/L as well as leukocytes in the blood. A chest x-ray, an ECG, and a CT scan of the head provided no conclusive findings.The patient was admitted to the hospital with a suspected diagnosis of a pulmonary infection. Empirical antibiotic therapy with ceftriaxone and azithromycin was initiated.TreatmentOn the third day of the patient’s hospitalization, a CT angiography showed no pulmonary embolism but revealed peribronchial thickening and peribronchovascular soft tissue stranding with subpleural reticulation in the lower lobes. Given the suspicion of an acute infection or inflammatory process, antibiotic therapy was expanded to include piperacillin-tazobactam.Blood cultures showed no bacterial growth after 2 days of incubation. A transthoracic echocardiogram revealed hyperdynamic left ventricular function.Despite antibiotic therapy, the patient’s dyspnea worsened. A repeat physical examination revealed platypnea and orthodeoxia. Contrast-enhanced echocardiography suggested platypnea-orthodeoxia syndrome. Furthermore, a large right-to-left shunt was observed. A patent foramen ovale was considered in the differential diagnosis as the cause of the right-to-left shunt. Transesophageal echocardiography confirmed the presence of a 9 × 16 mm patent foramen ovale. Following endovascular closure of the defect, anticoagulation with apixaban and clopidogrel was initiated.Shortly thereafter, the patient fell and suffered an intracranial hemorrhage, necessitating the discontinuation of anticoagulation. The patient’s cognitive function declined so drastically that, following treatment for her hemorrhage, she had to be discharged to long-term care.Discussion“Platypnea-orthodeoxia syndrome is relatively rare, defined as positional dyspnea and arterial hypoxemia characterized by a drop in peripheral oxygen saturation by greater than 4 mm Hg or arterial oxygen saturation greater than 5% when moving from the supine to upright position,” wrote the authors of the case report. In cases of persistent hypoxia that responds poorly to oxygen therapy, intracardiac shunts should also be considered in the differential diagnosis.This article was translated from Univadis Germany, part of the Medscape Professional Network.