Abstract
Platypnea-orthodeoxia syndrome (POS), the occurrence of dyspnea and arterial desaturation on changing from supine to sitting position, is a very rare phenomenon. Most case reports have been in association with an intra-atrial communication, and observation of this unusual physiological abnormality in pulmonary conditions has been extremely rare. We present a case of idiopathic pulmonary fibrosis where the patient developed characteristic symptoms of POS when it was complicated by Pneumocystis jiroveci pneumonia. This was objectively confirmed. A similar association has not been reported earlier in literature.