COVID-19 Infection Linked to Rare but Dangerous Postural Breathing Disorder Called Platypnea-Orthodeoxia Syndrome

Medical News: Medical experts are warning of a rare and often overlooked breathing disorder called Platypnea-Orthodeoxia Syndrome (POS) that is increasingly being recognized in individuals recovering from COVID-19 infections. This condition, which causes shortness of breath and low oxygen levels specifically when a person is sitting or standing, may be one of the key reasons why some people struggle with unexplained breathlessness long after being discharged from hospital.


COVID-19 Infection Linked to Rare but Dangerous Postural Breathing Disorder Called Platypnea-Orthodeoxia Syndrome

A new case study conducted by researchers from Unidade Local de Saúde (ULS) Amadora/Sintra in Amadora, Portugal, has shed light on this little-known complication of SARS-CoV-2 infections. Led by Dr. Teresa Valido, Ana Carolina Chumbo, Filipa Figueiredo, and Teresa Cruz, the case involved a 90-year-old man who developed Platypnea-Orthodeoxia Syndrome while recovering from a severe bout of COVID-19.
 
This Medical News report explores the patient’s case, the underlying mechanisms of POS, and how it may be underdiagnosed among post-COVID patients experiencing persistent breathing issues.
 
A Hidden Cause of Breathlessness
The elderly patient was admitted to the emergency department with dry cough and difficulty breathing, and was found to have dangerously low blood oxygen levels. A positive test for SARS-CoV-2 confirmed he was suffering from a severe COVID-19 infection. His condition worsened, requiring non-invasive ventilation due to ongoing hypoxemia. CT scans revealed extensive interstitial pneumonia affecting more than 60 percent of his lungs.
 
Despite receiving standard treatments including corticosteroids and antibiotics, and showing signs of slow recovery, the patient experienced intense breathlessness whenever he sat up or stood - even with supplemental oxygen. His oxygen saturation levels dropped from 92-94% while lying down to a dangerous 65-75% when upright.
 
This unusual phenomenon led doctors to perform blood gas analysis and contrast-enhanced imaging to look for common causes like cardiac defects or pulmonary arteriovenous malformations. However, none were found. The conclusion was clear: the patient was suffering from POS, triggered by fibrotic lung changes caused by COVID-19. These fibrotic scars and ventilation-perfusion mismatches in the lower lobes of the lungs likely created a form of physiological shunt that impaired oxygen exchange in upright positions.
 
What Is Platypnea-Orthodeoxia Syndrome
POS is a rare condition marked by positional shortness of breath (platypnea) and oxygen desaturation (orthodeoxia) that worsens when standing or sitting and improves when lying flat. It is usually caused by an abnormal connection between veins and arteries (a right-to-left shunt), either in the heart or lungs. In this case, COVID-induced lung fibrosis appears to have mimicked this mechanism, leading to hypoxia when upright.
 
POS can be mi sdiagnosed or overlooked because many recovering COVID patients are immobilized in bed and are often assumed to have fatigue or deconditioning rather than a positional oxygenation defect.
 
Key symptoms of POS include:
-Shortness of breath that intensifies in upright positions
 
-A significant drop in blood oxygen saturation upon standing
 
-Immediate relief when lying down
 
Diagnosis typically requires pulse oximetry and arterial blood gas analysis taken in both upright and supine positions. A drop in oxygen saturation of more than 5% when sitting or standing is considered indicative. Advanced imaging and cardiac bubble studies help rule out structural causes.
 
How POS Differs from Other Postural Disorders
It is important to distinguish POS from Postural Orthostatic Tachycardia Syndrome (POTS), another condition that worsens in upright positions but operates through a different mechanism. POTS is a disorder of the autonomic nervous system, causing a sharp increase in heart rate and symptoms like dizziness, palpitations, and fatigue upon standing. It is not characterized by oxygen desaturation.
 
Platypnea-Orthodeoxia Syndrome (POS)     
Key Issue: Oxygen desaturation with standing         
Underlying Cause: Right-to-left shunt or lung fibrosis        
Main Symptom: Dyspnea and low blood oxygen     
Diagnosis: Supine vs upright oxygen saturation       
Treatment Approach: Treat underlying cause (fibrosis)
 
Postural Orthostatic Tachycardia Syndrome (POTS)
Key Issue: Rapid heart rate increase upon standing
Underlying Cause: Autonomic nervous system dysfunction
Main Symptom: Dizziness, tachycardia, fatigue
Diagnosis: Supine vs upright heart rate and symptom check
Treatment: Lifestyle changes and medications
 
The Role of COVID19 in Triggering POS
Several studies have documented POS appearing during and after COVID-19 infections. Pulmonary fibrosis, especially in the lower parts of the lungs, and damage to pulmonary blood vessels (microangiopathy) are believed to be responsible. These issues impair oxygen delivery, especially when gravity pulls blood flow to the most affected areas in an upright position.
 
CT scans often show ground-glass opacities and fibrotic scarring near the lung bases in affected patients. This particular case confirmed the presence of such changes along with oxygenation problems that dramatically improved in the lying position.
 
The patient eventually improved with respiratory rehabilitation, physical therapy, and supportive oxygen therapy. He was discharged after 69 days in the hospital but continued home rehab for several weeks before oxygen therapy could be discontinued completely.
 
Why POS May Be Going Undiagnosed in Long COVID
Doctors caution that POS may be significantly underdiagnosed in people recovering from COVID-19, especially in those with long-term breathing difficulties or those who struggle to wean off oxygen. The symptoms can be subtle or confused with more common issues like fatigue or general deconditioning. Also, prolonged bed rest often masks the postural element of the disorder.

Rehabilitation, particularly guided physiotherapy and breathing exercises, appears to play a crucial role in recovery. The use of antifibrotic drugs may become an important treatment in the future, although more research is needed.
 
Conclusion
This case serves as a critical reminder that COVID-19 can lead to lingering, complex respiratory conditions such as Platypnea-Orthodeoxia Syndrome. POS is a serious but reversible complication that significantly affects quality of life and hospital recovery duration. Early recognition is vital. Any post-COVID patient with ongoing breathlessness, especially one who experiences symptoms when standing or sitting up, should be evaluated for this condition. Addressing POS through proper diagnosis, imaging, and tailored rehabilitation can make a profound difference in recovery and long-term respiratory function.
 
The study findings were published in the peer reviewed journal: Cureus.
https://www.cureus.com/articles/329377-platypnea-orthodeoxia-syndrome-in-relation-to-severe-sars-cov-2-infection#!/
 
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