Pleural effusion is a condition wherein excess fluid builds up in between the layers of pleura outside the lungs. In laymen terms the condition is very commonly referred to as “water on the lungs,” or sometimes incorrectly called “water in the lungs”. The pleura are thin membranes that line the lungs and the inside of the chest cavity and act to lubricate and facilitate breathing. Normally, a small amount of fluid is present in the pleura.
Pleural effusion can be broadly divided into two main categories based on the protein content of the fluid.
• Transudative Pleural Effusion: The excess fluid accumulated here is protein-poor and watery.
• The most common causes of transudative (watery fluid) pleural effusions include:
o Heart failure
o Pulmonary embolism
o Post open heart surgery
• Exudative pleural effusions – is due to accumulation of a protein rich pleural fluid and are most commonly caused by:
o Pulmonary embolism
o Kidney disease
o Inflammatory disease
o Other less common causes of pleural effusion include: o Autoimmune disease
o Bleeding (due to chest trauma)
o Chylothorax (due to trauma)
Certain medications, abdominal surgery and radiation therapy may also cause pleural effusions. Pleural effusion may occur with several types of cancer including lung cancer, breast cancer and lymphoma. In some cases, the fluid itself may be malignant (cancerous), or may be a direct result of chemotherapy.
The tests most commonly used to diagnose and evaluate pleural effusion include:
o Chest x-ray
o Computed tomography (CT) scan of the chest
o Ultrasound of the chest
o Thoracentesis (a needle is inserted between the ribs to remove a biopsy, or sample of fluid)
o Pleural fluid analysis (an examination of the fluid removed from the pleura space)
For patients in whom the cause of the pleural effusion remains undiagnosed even after these test a diagnostic thoracoscopy may be required to ascertain the cause of the effusion. It is a minimally invasive technique, also known as video-assisted thoracoscopic surgery, or VATS, performed under general anaesthesia that allows for a visual examination of the inside of the pleural cavity and take biopsies. Often, treatment of the effusion is combined with diagnosis in these cases.
The treatment of pleural effusion is aimed at curing the cause of the effusion. It also depends on how much respiratory problems such as shortness of breath or breathing difficulty it is causing to the patient.
Treatment of the underlying cause may treat the pleural effusion also like treatment of congestive heart failure, kidney or liver disease. An effusion that is cancerous or malignant may also require treatment with chemotherapy, radiation therapy.
In cases where the pleural effusion is significantly large and causes breathing difficulties the fluid may need to be drained for symptomatic relief. This can be done by a therapeutic thoracentesis where under ultrasound guidance the doctor inserts a needle into the cavity containing fluid and sucks out maximum amount of fluid. In some cases, a chest tube (called tube intercostal tube drainage) may be required.
In case the pleural effusion is recurrent and has not responded to other methods including drainage, a sclerosing agent (a type of drug that deliberately induces scarring) occasionally may be instilled into the pleural cavity through a tube thoracostomy to create a an inflammatory response that leads to the two layers of pleura becoming densely stuck to each other thus obliterating the space and hence preventing the fluid reaccumulate. This is called pleurodesis.
Pleural effusions that cannot be managed through drainage or pleural sclerosis may require surgical treatment.
The two types of surgery include:
Video-assisted thoracoscopic surgery (VATS)
This is a minimally-invasive technique that is performed through 1 to 3 small (approximately 5mm to 12 mm key-hole) incisions in the chest. Also known as thoracoscopic surgery, this procedure is effective in managing pleural effusions that are difficult to drain or recur due to malignancy. Sclerosing agent may such as sterile talc or an antibiotic may be instilled into the pleural cavity. Sometimes the surgeon choses to remove the parietal pleural layer (the layer that lines the inside of chest wall) called Pleurectomy.
Each patients need to be carefully evaluated and a tailor-made plan is developed to determine the safest treatment option.
How can Pneumothorax be prevented?
There is no way to prevent a collapsed lung, although the risk of its recurrence may be reduced. In case a person develops spontaneous pneumothorax there is fair possibility of its recurring within 2 years.
One can reduce the chances of recurrence to some extent by:
Air Travel should be avoided for at least one week after the complete resolution of pneumothorax which has been confirmed on chest x-ray.
Deep sea diving should be discouraged in patients who are prone to pneumothorax unless a definitive management in the form of surgery has been done and the doctor has cleared for such activities.