Pleural Disorders

The lungs are surrounded by the pleura. The pleura consist of two thin layers (the inner layer called the visceral pleura and the outer layer called the parietal pleura). In between the two layers is a very thin space (called the pleural space). Normally this space is filled with a small amount of fluid. The fluid provides lubrication, helping the two layers glide smoothly past each other as they move, during inspiration and expiration. 

If air, blood, or excessive fluid accumulates in the pleural space, then this hinders the lungs ability to expand normally when breathing.

Pneumothorax
A pneumothorax is the condition when air is in the pleural space.

Causes – a pneumothorax occurs because of a small tear in the pleura, allowing air to leak inside. Air then begins to accumulate between the inner pleural layer and the outer pleural layer. Pneumothoraces may occur because of trauma (called traumatic pneumothorax), or may occur without trauma (called spontaneous pneumothorax):

Signs and symptoms – the severity of the symptoms depend on the amount of air that has accumulated. There is usually a sudden onset of shortness of breath and chest discomfort. There may be a decrease in oxygen saturations.

Investigations – Oxygen saturation should be frequently monitored. Auscultation may reveal decreased breath sounds on the affected side. The chest x-ray will reveal the white line of the inner pleura (visceral pleura), and outside this line there will be absence of lung markings. In the upright chest x-ray, this will first be visible in the upper zone of the affected lung.

Treatment – oxygen should be given to any patient that is short of breath. Small pneumothoraces may not required treatment, only observation. Medium pneumothoraces require the air to be aspirated out. Large pneumothoraces require an intercostal chest drain to be inserted.

Complication – if the pneumothorax continues to increase in size, then it can eventually become so large that it compresses the major blood vessels (such as the aorta and vena cava) nearby. This then results in hypotension. This is called a tension pneumothorax.

Tension pneumothorax - 

There will be shortness of breath and decreased oxygen saturations. Auscultation will reveal absent breath sounds on the affected side, as air is not moving into the lung. Other signs of a tension pneumothorax that are sometimes present are tracheal deviation away from the affected side, and distended jugular veins. Tension pneumothorax is a life threatening condition that requires immediate treatment.

Treatment is to insert a large catheter into the chest. The position of the needle is in the middle of the clavicle bone (midclavicular line) then vertically down until in-between the 2nd and 3rd ribs (second intercostal space). The needle must be inserted at that location. The needle pierces the outer pleural layer, and allows the accumulated air to escape through it. After this emergency treatment, an intercostal chest drain must be inserted.

Hemothorax
A hemothorax is the condition when blood is in the pleural space.

Causes – hemothorax usually occurs due to trauma to the chest. This can cause a tear in the pleura, allowing nearby damaged blood vessels to bleed into it. Blood then begins to accumulate between the inner pleural layer (visceral pleura) and the outer pleural layer (parietal pleura).

Signs and symptoms – the severity of the symptoms depends on the amount of blood that has accumulated. There is usually shortness of breath and chest discomfort. There may be a decrease in oxygen saturations.

Investigations – oxygen saturation should be frequently monitored. Auscultation may reveal decreased or absent breath sounds over the area of hemothorax. The chest x- ray will reveal the blood in the affected lung, which looks cloudy white on x-ray. An upright chest x-ray will show this blood in the lower zone of the affected lung, as gravity causes fluid to fall to the bottom.

Treatment – oxygen should be given to any patient that is short of breath. Moderate to large hemothoraces require insertion of an intercostal chest drain. If a large volume of blood is lost into the pleural space then a blood transfusion may be required.

Pleural Effusion
A pleural effusion is the condition when excessive pleural fluid is in the pleural space.

Causes – pleural effusion can be a complication of many different diseases. For example, it can occur because of pneumonia, tuberculosis, heart failure, malignancy, or liver failure. 

Signs and symptoms – the severity of the symptoms depends on the amount of fluid that has accumulated. There is usually shortness of breath and a chest discomfort. There may be a decrease in oxygen saturations.

Investigations – oxygen saturation should be frequently monitored. Auscultation may reveal decreased or absent breath sounds over the effusion area. The chest x-ray will reveal the fluid in the affected lung, which looks cloudy white on x-ray. An upright chest x-ray will show this fluid in the lower zone of the affected lung, as gravity causes fluid to fall to the bottom.

Treatment – oxygen should be given to any patient that is short of breath. Moderate effusions require aspiration. Large effusions require insertion of an intercostal chest drain. It is also important to investigate and treat the underlying cause. If it is not possible to treat the underlying cause, then monthly drainage may be required to relieve symptoms.