Platypnoea–orthodeoxia syndrome after pulmonary lobectomy: a rare entity with a difficult diagnosis

Abstract

Platypnoea–orthodeoxia syndrome (POS) is a rare clinical entity. It is characterized by position-dependent dyspnoea and oxygen desaturation in the upright position with orthodeoxia resolving in the supine position, and is mainly associated with cardiac defects. Only 9 cases of post-lobectomy POS have been reported in the literature. We describe a case of POS in a woman who underwent a lobectomy and in whom POS was diagnosed and treated.

Reversible platypnoea-orthodeoxia syndrome

“…The presence of an anatomical defect, particularly if small, may not by itself manifest this condition. A coexisting functional condition can be identified in some 5. The anatomical and functional components interplay; the upright position increases the magnitude of the anatomical defect thereby accentuating the right-to-left shunt resulting in symptoms 2 4 6…”

“…There have been several case reports, which report many causes that lead to an accentuated right-to-left shunt in patients with an existing intracardiac shunt, and therefore, platypnoea and orthodeoxia. These include aortic atherosclerosis and subsequent elongation of the ascending aorta and aortic root dilation, progressive kyphosis, pneumonectomy, lobectomy, constrictive pericarditis, pericardial effusion, pulmonary embolism, diaphragmatic paralysis causing cardiac compression and after transcatheter closure of ruptured sinus of valsalva 2 4–6 8–11…”

“…In the upright position, there was further increased stretching and widening of the defect aided by gravity permitting the shunt even at normal intracardiac pressures. It, therefore, manifested as a position-dependent and flow-mediated opening of the patent foramen ovale resulting in an augmented right-to-left shunt 2 5 10–12…”

“…The most common identified specific causes are a patent foramen ovale, other atrial septal defects or arteriovenous malformations in the lung bases such as in hepatopulmonary syndrome 3. This extracardiac or intracardiac right-to-left shunt defined as the anatomical component gets accentuated in the presence of a functional component resulting in an augmented shunt phenomenon 4 5. Irrespective of the aetiology, the pathophysiological mechanism is a right-to-left shunt and the identification of both the anatomical and functional components that lead to this syndrome is crucial to its management 2 6.…”