What Are Pleurisy and Other Disorders of the Pleura?

Pleurisy (PLUR-is-see) is inflammation (swelling) of the pleura. The pleura is a large, thin sheet of tissue (membrane) that wraps around the outside of your lungs and lines the inside of your chest cavity.

Between the layer of the pleura that wraps around your lungs and the layer that lines your chest cavity is a very thin space. This is called the pleural space. Normally it's filled with a small amount of fluid—about 4 teaspoons full. The fluid helps the two layers of the pleura glide smoothly past each other as your lungs breathe air in and out.

Pleurisy occurs when the two layers of the pleura become red and inflamed. Then they rub against each other every time your lungs expand to breathe in air. This can cause sharp pain with breathing.

Infections like pneumonia are the most common cause of swelling, or inflammation, of the pleura and pleurisy.

Other Disorders of the Pleura

Pleural Effusion

In some cases of pleurisy, excess fluid builds up in the pleural space. This is called a pleural effusion. The buildup of fluid usually forces the two layers of the pleura apart so they don't rub against each other when you breathe. This can relieve your pain.

However, a large amount of extra fluid can push the pleura against your lung until the lung, or a part of it, collapses. This can make it hard for you to breathe.

In some cases of pleural effusion, the extra fluid gets infected and turns into an abscess. This is called an empyema (em-pi-E-ma).

You can develop a pleural effusion if you don't have pleurisy. For example, pneumonia, heart failure, cancer, or a pulmonary embolism can lead to a pleural effusion.

Pneumothorax

Air or gas also can build up in the pleural space. This is called a pneumothorax (noo-mo-THOR-aks). It can result from acute lung injury or a lung disease like emphysema. Lung procedures, like surgery, drainage of fluid with a needle, examination of the lung from the inside with a light and a camera, or mechanical ventilation, also can cause it.

The most common symptom is sudden pain in one side of the lung and shortness of breath. A pneumothorax also can put pressure on the lung and cause it to collapse.

If the pneumothorax is small, it may go away on its own. If it's large, you may need to have a tube placed through your skin and chest wall into the pleural space to remove the air.

Hemothorax

Blood also can collect in the pleural space. This is called hemothorax (he-mo-THOR-aks). The most common cause is injury to your chest from blunt force or chest or heart surgery. Hemothorax also can occur in people with lung or pleural cancer.

Hemothorax can put pressure on the lung and force it to collapse. It also can cause shock, a state in which not enough blood and oxygen reach important organs in the body.

Outlook

Pleurisy and other disorders of the pleura can be serious, depending on what caused the inflammation in the pleura.

If the condition that caused the pleurisy or other pleural disorders isn't too serious and is diagnosed and treated early, you usually can expect a full recovery.

August 2007