Pleurisy

Pleurisy (or pleuritis) occurs when the double membrane (pleura) that lines the chest cavity and surrounds each of your lungs becomes inflamed.

One layer of the pleura, which is just a few cells thick, overlies each lung.  The other layer lines the inner chest wall.  When you breathe in, the large muscle separating the chest cavity from the abdominal cavity (diaphragm) contracts and your chest wall expands, causing your lungs to expand.  The two layers of pleura rub against each other with almost no friction, allowing your lungs to expand and contract without any resistance from the lining of the chest wall.

When inflamed, the two layers of the membrane in the affected side of your chest rub against each other, producing pain when you inhale and/or exhale.  Between breaths, you feel almost no pain.  At times, pleurisy causes an accumulation of fluid in the chest cavity (pleural effusion).

Causes and Development

Pleurisy occurs as a complication of many things.  The underlying medical conditions that can cause pleurisy are numerous and include:

• An acute viral infection, such as the flu (influenza)
• Bacterial or viral infections of the lungs (pneumonia) where the infected portion of the lung involves the pleural surface
• Autoimmune conditions such as lupus, rheumatoid arthritis and autoimmune hepatitis
• Tuberculosis and other infections
• A blood clot in an artery of your lungs (pulmonary embolism)
• Pancreatitis
• Cancer
• Trauma (injury) to the chest or after heart surgery.

Sometimes a cause cannot be found (ideopathic pleurisy).

Signs and Symptoms

Pleurisy typically causes sharp chest pain, almost always during the act of breathing.  There may also be dry cough, fever and chills, pain when moving, or fast, shallow breathing – shortness of breath.  The patient will typically be able to point to the exact location of the pain.  In some people, the pain spreads to the neck, shoulder, or abdomen.

When an accumulation of fluids is associated with pleurisy, the pain usually disappears because the fluid serves as a lubricant.  However, if enough fluid accumulates, it puts pressure on your lungs and interferes with their normal function, causing shortness of breath.  If the fluid becomes infected, the signs and symptoms of dry cough, fever and chills may appear.

Diagnosis and Tests

A doctor may make a diagnosis based on your signs and symptoms.  Upon examining you and listening to your chest, your doctor may hear a "friction rub" that sometimes sounds like the crunching sound of walking on very dry snow.

You may also undergo the following diagnostic procedures:

• Imaging. A chest X-ray may show an area of inflammation in your lungs that indicates pneumonia.  Your doctor will want to investigate an unexplained abnormality seen on an X-ray with additional imaging, usually beginning with a computerized tomography (CT) scan.  In a CT procedure, a computer translates information from X-rays into images of thin sections (slices) of your chest.  CT scans produce more detailed images of your internal organs than do conventional X-ray studies.  Sometimes doctors want a special type of chest X-ray in which you lie on your side where the pleurisy is to see if there's any fluid that doesn't appear on a standard chest X-ray.  This type of X-ray is called a decubitus chest X-ray.
• Blood test. A blood test may tell your doctor whether your lungs are infected and what type of infection you have.  Other blood tests may also detect an autoimmune disorder such as rheumatoid arthritis or lupus in which the initial sign is pleurisy.
• Thoracentesis. To remove fluid for laboratory analysis, your doctor may suggest a procedure called thoracentesis.  In this procedure, your doctor first injects a local anesthetic, then inserts a needle through your chest wall between your ribs to remove fluid.  In addition, a sample of tissue (pleural biopsy) for microscopic analysis may be obtained if your doctor is concerned that the fluid collection may be caused by tuberculosis or cancer.  If only a small amount of fluid is present, your doctor may insert the needle with the help of ultrasound over the site of the fluid.
• Video-assisted thoracic surgery (VATS). Another way of obtaining a sample of pleural tissue is by a surgical procedure called video-assisted thoracic surgery.  In VATS, a tube is inserted to collapse a lung to about one-quarter its normal size.  This creates a space through which your doctor can insert a pen-sized instrument through your chest wall to take a tissue sample under video guidance.

Treatment and Prevention

The most important goal in relieving pleurisy or pleural effusions is treatment of the underlying condition that's causing your signs and symptoms.  For example, if the cause of pleurisy is a bacterial infection of the lung (pneumonia), an antibiotic may control the infection.  But, for pleurisy due to a viral infection, antibiotics won't be effective.

Over-the-counter or prescription nonsteroidal anti-inflammatory drugs (NSAIDs) may help relieve some of the signs and symptoms of pleurisy.  Prescription codeine may help control a cough as well as the pain.  If there is a large buildup of fluid, the patient may need to stay in the hospital to have the fluid drained over a period of several days through a tube inserted into the chest.

Even though the cause may not be known, the problem can still be treated.

The sharp, fleeting pain in your chest that pleurisy causes is made worse by coughing, sneezing, moving and deep breathing.  You may find relief from pain when you hold your breath or when you apply pressure over the painful area.

Prognosis

The outcome of treatment may depend on the seriousness of the underlying disease.  Most cases of pleuritis of unknown cause heal with time.