Can A Chest X-ray Tell Us If There Is Fluid In The Lungs?
Yes, it can, but not all the time. When we say fluid in the lungs, we may mean that we have pulmonary edema. Fluid can also be found around the lungs and is called a pleural effusion. Fluid can be found in the mediastinum or compartment between the lungs. Fluid can therefore be found in multiple anatomic sites in the chest.
Causes of pulmonary edema
Fluid in the lungs or pulmonary edema often presents with breathlessness and distress. I see this most common from heart conditions. These can be heart failure, heart attacks, abnormalities of the heart valves and rhythm disturbances of the heart.
There are many causes of pulmonary edema related to non heart conditions. Some of the more common causes include: kidney failure, drugs, high altitude edema, oxygen therapy, near downing, bruising and trauma to name some. The history helps as the chest X-ray often does not reveal the specific cause.
What does edema look like on chest X-ray?
on chest x ray, we may see nothing when it is very mild. As it progresses, it can be seen in the lung between the airspaces or in the interstitial compartment as haziness or thickening of the interstium. As it becomes more severe, we can see it spill over into the airspaces and cause white areas throughout the lungs.
An enlarged heart often helps us determine the cause as related to heart disease, but this is not always seen. Distinguishing the causes often depends on getting a good history and further testing. The appearance of pulmonary edema or fluid in the lungs is the same for most of the causes.
Pleural Effusion or fluid around the lung often accompanies pulmonary edema or fluid in the lungs. Pleural effusion can also be caused by many conditions. Some of these include heart failure, liver and kidney failure, after heart attacks and after bypass surgery, cancers, infections and inflammatory conditions.
History and sampling the fluid can identify the cause. Treatment is targeted to the underlying cause. Fluid can also be withdrawn brought a needle inserted into the fluid for symptomatic relief. On chest X-ray, fluid will appear as white area layering by the diaphragms. A small amount of fluid may not be seen. Larger effusions may push the mediastinum to the opposite side.
Fluid in the mediastinum
Fluid in the mediastinum or compartment between the lungs is often found after surgery and is less common. Infections of the mediastinum can be accompanied by abscesses or collections of pus. We usually do not see fluid in the mediastinum on chest X-ray. A CT will be needed for diagnosis.
Fluid in the lungs usually means pulmonary edema which is often accompanied by pleural effusion or fluid around the lung. There are many causes as outlined above. We can usually see fluid in the lungs as it progresses. We often can not tell the cause. History, further testing and imaging can be helpful. Treatment is targeted to the underlying cause.