There is a thin layer of fluid between the lungs and the chest wall, in the human body. This fluid is essential because it acts as a lubricant between the chest walls and the lungs, when we breathe. The cavity or space between the chest wall and the lungs, where this liquid accumulates, is called the pleura and the fluid is called pleural fluid. An abnormal increase in the quantity of pleural fluid causes the chest walls to separate from the lungs. This condition is known as pleural effusion.
What Causes Pleural Effusion
Pleural effusion can be broadly classified into two types; transudative and exudative pleural effusion.
Transudative pleural effusion is caused by fluid leaking into the pleural space. Such leakage may be due to a variety of reasons but the most common one is the failure of the left ventricle in the human heart. People suffering from complications after heart surgery, have also often been diagnosed with transudative pleural effusion. Pulmonary embolism and cirrhosis are other common causes for this form of pleural effusion.
Exudative pleural effusion is caused by leaky blood vessels, which are in turn, caused mainly due to lung disease. Some of the most common causes are lung infections, tuberculosis, bacterial pneumonia, pulmonary embolism, breast cancer and lung cancer. Drug induced lupus are sometimes produced by some type of medication and this can also result in pleural effusion.
Pleural effusion caused due to medicines is not very acute, as the pleural fluid starts reducing in volume as soon as the medication procedure is over. Arthritis causes inflammation of body parts and in certain cases, it may also cause inflammation of the pleura. Systematic lupus erythematosus and accidental infusion of fluids, are also among the other major causes. Rarer reasons are pancreatic, liver and kidney diseases, viral and fungal infections and mesothelioma.
The possible signs of pleural effusion are:
- Compression of the lungs
- Chest pain (does not occur in all patients)
- Difficulty in breathing
- Cough and fever with empyema (when pneumonia has caused the effusion)
- Dyspnea (breathlessness)
The basic steps included in the treatment are diagnosing the problem, removing the fluid and treating the causal disease of the effusion (such as pneumonia, collapsed ventricle etc.). The first step of diagnosis is a simple chest X-Ray. But confirming the presence of excess pleural fluid is done after an ultrasound or a CT scan or both. The next important step in the diagnosis is to find out what caused the liquid to accumulate in the pleura. The cause can be determined by getting a sample of the fluid.
The process involved in extracting a sample of this liquid and removing a large amount of it, is called therapeutic thoracentesis. The amount of liquid removed lies within the range of 30 ml to 2 liters. In certain cases, the fluid is removed by inserting an intercostal drain into the pleura. In case the patient suffers from cancer, the fluid is removed by inserting a chest tube, and allowing the fluid to drain out. This process may take more than one day.
If the fluid keeps on accumulating continuously, then repeated effusions of the fluid are done through chemical or surgical pleurodesis. In this process, both the pleural surfaces are scarred, hence prohibiting the accumulation of the liquid. Regardless of whatever process is undertaken to remove the fluid, antibiotics are compulsorily administered. The final step in the treatment is addressing the basic cause.
In case of patients suffering from bacterial pleural effusion, antibiotics can simply be used. People with cancer are treated with chemotherapy, radiation therapy or surgery. Diuretics are given to people suffering from pleural effusion, caused by heart problems.
Pleural effusion caused by pneumonia, tuberculosis, bacterial infections and arthritis, can be diagnosed and treated with ease. But when the root cause is not known, diagnosing and removing the excess fluid becomes extremely important.