From the Guidelines
The main causes of asymmetric pulmonary edema include unilateral lung injury, gravitational effects in side-lying positions, unilateral pulmonary venous obstruction, and re-expansion pulmonary edema. Unilateral lung injury can occur from pneumonia, trauma, or aspiration affecting only one lung 1. Gravitational effects become significant when a patient lies on one side for prolonged periods, causing fluid to accumulate in the dependent lung. Unilateral pulmonary venous obstruction may result from conditions like pulmonary vein thrombosis, tumor compression, or fibrosing mediastinitis affecting vessels on one side. Re-expansion pulmonary edema can develop after rapid drainage of a large pleural effusion or pneumothorax, causing increased permeability and fluid accumulation in the affected lung. Other causes include unilateral neurogenic pulmonary edema following head trauma or seizures, and pulmonary contusion from chest trauma.
Some studies suggest that mitral stenosis, a condition where the mitral valve is narrowed, can also lead to pulmonary edema due to increased pressure in the left atrium and pulmonary veins 1. However, this is more likely to cause symmetric pulmonary edema. The most recent and highest quality study on this topic is from 2020, which discusses the management of mechanical ventilation in patients with aneurysmal subarachnoid hemorrhage, and highlights the importance of identifying and addressing the underlying cause of pulmonary edema 1.
Treatment of asymmetric pulmonary edema depends on identifying and addressing the underlying cause while providing supportive care, including:
- Oxygen therapy
- Positioning to reduce fluid accumulation in the dependent lung
- Sometimes diuretics like furosemide if fluid overload is present It is essential to note that the treatment should be tailored to the individual patient's needs and underlying condition. In some cases, more invasive interventions such as mechanical ventilation or surgery may be necessary.
In terms of morbidity, mortality, and quality of life, it is crucial to prioritize early recognition and treatment of asymmetric pulmonary edema to prevent long-term complications and improve patient outcomes. According to a study from 2016, mechanical ventilation can have significant effects on hemodynamics and lung function, and should be used judiciously in patients with pulmonary edema 1. Another study from 2008 highlights the importance of cautious medical therapy in patients with valvular heart disease and pulmonary congestion, including the use of digitalis, diuretics, and ACE inhibitors 1.
Overall, the management of asymmetric pulmonary edema requires a comprehensive approach that takes into account the underlying cause, patient's overall condition, and potential complications. By prioritizing early recognition and treatment, and using evidence-based therapies, healthcare providers can improve patient outcomes and reduce morbidity and mortality.
From the Research
Causes of Asymmetric Pulmonary Edema
- The exact causes of asymmetric pulmonary edema are not explicitly stated in the provided studies, but several factors that contribute to acute pulmonary edema are mentioned 2, 3, 4, 5.
- According to the study published in 2014, the main pathologies that can lead to acute pulmonary edema include:
- Arterial high blood pressure (HBP)
- Dilated cardiomyopathy
- Ischemic heart disease
- Valvular heart disease
- Pre-existing atrial rhythm disorders 5.
- The analysis of precipitating factors revealed possible triggering conditions such as:
- Inadequate physical effort on the background of treatment discontinuation
- High sodium diet
- Prolonged ischemic episode due to inadequate physical effort
- Rhythm disorder with rapid ventricular response (atrial fibrillation, atrial flutter) 5.
- Another study published in 2025 describes a specific type of acute pulmonary edema called sympathetic crashing acute pulmonary edema (SCAPE), which is characterized by sudden, severe pulmonary edema and hypertension, resulting in respiratory distress and hypoxemia 4.
- The study suggests that SCAPE is associated with significantly elevated afterload with fluid maldistribution into the pulmonary system, and that evaluation and resuscitation should occur concurrently 4.