Platypnea-Orthodeoxia Syndrome after SARS-CoV-2 interstitial pneumonia: an overview and an update on our patient

Abstract

Platypnea-Orthodeoxia Syndrome (POS) is a clinical entity defined as positional dyspnoea (platypnea) and arterial desaturation (orthodeoxia) that occurs when sitting or standing up and usually resolves by lying down. Up to April 25th 2021, eleven cases of POS after SARS-CoV-2 pneumonia have been reported on Pubmed. Accordingly, SARS-CoV-2 infection may be considered as an emergent cause of POS due to an increase in ventilation/perfusion (V/Q) mismatch. In this article we provide an update on the patient with POS after fibrotic evolution of SARS-CoV-2 interstitial pneumonia, which we previously reported and we discuss the case reports of POS due to SARS-CoV-2 infection.

Figure 1.

CT at the 1st hospitalization (March 2020): Bilateral ground glass opacities with patchy distribution - visual score of 35%.

Figure 2.

CT scan after worsening gas exchange (April 2020): Bilateral segmental pulmonary embolism involving the branch for the posterior segment of the right upper lobe, anterior segmental branch of the left upper lobe and the branch for the dorsal segment of the left lower lobe. Worsening of ground glass opacities (visual score of 60%).

Figure 3.

CT scan after 2 weeks from the previous one (April 2020): Fibrotic evolution of interstitial pneumonia. Decrease of the ground glass opacities with peribronchial consolidating areas of organized appearance with contextual traction bronchiectasis. Visual score of 60%.

Figure 4.

CT scan at the patient’s discharge (June 2020): Ground glass opacities with patchy distribution, persistence of the basal fibrotic pattern, with traction bronchiectasis. Presence of pneumomediastinum. Visual score of 50%.

Figure 5.

CT scan at 2nd hospitalization (August 2020): The parenchymal fibrosing pattern is globally worsened (extension score 75%), showing new ground glass areas (superior lobes) and traction bronchiectasis. New parenchymal peribronchial consolidation in the inferior left lobe, suggestive of infection (maybe of fungal nature). Significant decrease of the extension of the known pneumomediastinum.

Figure 6.

CT scan after 5 weeks since admission (October 2020): The parenchymal fibrosing pattern is unchanged. The known parenchymal peribronchial consolidation of the inferior left lobe is also unchanged. Significant increased the known pneumomediastinum.

Figure 7.

Ventilation/Perfusion (V/Q) and shunt in healthy and in POS. Passing from the supine position to the orthostatic one (left to right in the image), a V/Q gradient is formed physiologically. Due to gravity, in the orthostatic position the upper zone of the lung is highly ventilated but poorly perfused (Zone I) in contrast to the middle one (Zone II) and the lower one (Zone III), where more perfusion is present. Parenchymal lung diseases involving mostly the bases of the lung can cause intrapulmonary shunting by accentuating the V/Q mismatch. Legend: Blue arrow: Deoxygenated blood; Red arrow: Oxygenated blood; Purple arrow: Blend of deoxygenated and oxygenated blood; Black cross: lung zone with interstitial disease.