ABSTRACT
INTRODUCTION: Platypnea-orthodeoxia is an uncommon syndrome characterized by dyspnea and deoxygenation accompanying a change to a sitting or standing posture from a recumbent position. It is usually related to interatrial communications, although several other disorders associated with platypnea-orthodeoxia syndrome have been reported. However, the precise mechanisms are unknown. CASE PRESENTATION: We present the case of a 75-year-old Caucasian woman with chronic renal failure due to vasculitis who was admitted with fever and respiratory failure. She was found to have both Pneumocystis jiroveci and Cytomegalovirus pneumonia. She was HIV negative. Severe platypnea and orthodeoxia were major features of her illness with no history of respiratory, liver or cardiac disease. Further investigation with contrast echocardiography revealed no intracardiac or intrapulmonary shunts. Although one case involving Pneumocystis jiroveci pneumonia and platypnea has been previously reported, to the best of our knowledge, this is the first time that two opportunistic pathogens have been accompanied by platypnea and orthodeoxia. As both lung bases were predominantly affected and no obvious explanation was found, platypnea and orthodeoxia were attributed to significant areas of low or zero ventilation/perfusion (V/Q) ratio. CONCLUSION: Platypnea-orthodeoxia is a rare and usually underestimated syndrome. Intracardiac shunts and anatomic pulmonary vascular shunts are the most common etiologic associations. However, if a detailed examination reveals no obvious intracardiac or intrapulmonary shunting combined with extensive pulmonary lesions, then severe V/Q mismatching should be considered as the probable explanation.
