A pleural effusion is the accumulation of fluid between the layers of pleura that cover the lung. This is a common finding on chest X-ray which can have many causes such as : infection, heart failure, cancer, inflammatory conditions such as lupus, cirrhosis, post heart surgery, pulmonary embolism (clots to the lungs) amongst other causes. The chest X-ray may not show small effusions but the larger ones are often detected.
A pleural effusion may or may not necessarily be the cause of your symptoms. Some people who have better health and more lung reserve may accumulate large amounts of fluid before they develop breathlessness. Others who are sicker may develop symptoms when the fluid accumulation is small.
As listed above, there is often an underlying condition which is responsible for the effusion. Sometimes this is evident on a chest X-ray. When the heart is big and there is fluid in the lungs, then heart failure is the most likely diagnosis. When there is a mass in the lung, then the effusion is likely due to cancer. In some cases further testing will be needed.
The consistency of the fluid is important for identifying the cause. This unfortunately can only be done with sampling of the fluid. Fluid no matter if it is blood, pus or water will look the same. More complex fluid in the pleural space is often associated with infections, inflammatory conditions, blood clots and cancer. More simple fluid can be seen with cirrhosis, heart failure and kidney conditions.
Since a pleural effusion can have many causes, it is important for your doctor to direct further testing and diagnosis in conjunction with your history. For example, if you have heart failure then the effusion can be treated with medications. If you have a smoking history with an effusion, then further testing may include further imaging with cat scan and possible sampling of the fluid to exclude cancer. If you have liver or kidney conditions, then the effusion may simply be secondary.
If a pleural effusion is identified on a chest X-ray, your doctor may order a cat scan to further evaluate. Often a cat scan will show findings that a chest X-ray will not. This is especially true if a cancer, clot or lung infection is suspected. If the diagnosis is still not apparent, then a thoracentesis may be performed which involves directly sampling the fluid. This can also help with diagnosis.
In many cases, the treatment consists of treating the underlying condition. If the effusion is symptomatic and large, then a thoracentesis can be performed for symptom relief. This involves placing a needle into the pleural space or covering of the lung and removing fluid. When there is fluid around the lung, it can cause problems breathing which should be relieved with this procedure.
In all cases, it is important to have a team of doctors directing your care depending on what the underlying condition is. The clinical information is of vital importance for the best treatment of pleural effusions found on chest X-ray.