Respiratory Medicine, Christian Medical College, Vellore, Tamil Nadu, India
Pulmonary Medicine, Christian Medical College, Vellore, Tamil Nadu, India.
BMJ Case Rep. 2023 Oct 31;16(10):e255587. doi: 10.1136/bcr-2023-255587.
Platypnoea-orthodeoxia syndrome is characterised by dyspnoea and oxygen desaturation in the upright position usually caused by an extracardiac shunt and less often due to dynamic factors that accentuate an intracardiac right-to-left shunt. In our patient, the collapse of lower lobe of left lung secondary to bronchial stenosis due to endobronchial tuberculosis and resultant mediastinal shift was the factor that led to an otherwise unrecognised intracardiac right-to-left shunt leading to platypnoea-orthodeoxia. We postulate that there would have been an increased stretching and widening of a patent foramen ovale in the upright position due to gravity resulting in an increased shunt despite normal intracardiac pressures. Once the patency of the left main bronchus was restored by deploying a stent, the left lower lobe expanded, the mediastinum returned to its normal position and there was resultant resolution of the platypnoea-orthodeoxia. This interesting observation may be useful in managing similar scenarios in the future.
并发性直立位低氧血症-低通气综合征的特征为直立位呼吸困难伴低氧血症，通常由心外分流引起，较少由可加重心内右向左分流的动力因素引起。在我们的患者中，支气管狭窄导致左下肺萎陷，继而出现纵隔移位，是导致原本不明显的心内右向左分流的原因，从而导致并发性直立位低氧血症-低通气综合征。我们推测，由于重力作用，在直立位时，卵圆孔未闭会发生更多的伸展和增宽，从而导致尽管心内压正常，但分流增加。一旦通过放置支架恢复左主支气管的通畅性，左下肺叶扩张，纵隔恢复正常位置，由此并发性直立位低氧血症-低通气综合征得到缓解。这一有趣的观察结果可能对未来处理类似情况有所帮助。
