Pleurisy is an inflammation of the pleura, the membranes that line the thoracic cavity and fold in to cover the lungs. Pleurisy may be characterized as dry or wet.
In dry pleurisy, little or no abnormal fluid accumulates in the pleural cavity, and the inflamed surfaces of the pleura produce an abnormal sound called a pleural friction rub when they rub against one another during respiration. This rubbing may be felt by the affected person or heard through a stethoscope applied to the surface of the chest. In wet pleurisy, fluids produced by the inflamed tissues accumulate within the pleural cavity, sometimes in quantities sufficient to compress the underlying lung and cause shortness of breath.
Because the pleura are well supplied with nerves, pleurisy can be very painful. Pleurisy is commonly caused by infection in the underlying lung and, rarely, by diffuses inflammatory conditions such as lupus erythematosus. Treatment of pleurisy includes pain relief, fluid evacuation, and treatment of the underlying disease.
Classification of pleurisy
(a) If the process leads to a fibrinous deposit, it is known as dry pleurisy.
(b) If an addition, there is much serous fluid, it is called pleurisy with effusion or wet pleurisy, and
(c) If pus formation occurs, the affection is described as purulent pleurisy or empyema. It must be noted, however, that these three conditions are in reality the three stages in any given case.
Who gets pleurisy?
Pleurisy can attack people of all ages, from children to the very aged. When it is caused by viral infection, it is a disease that doctors tend to associate with young people. When it is associated with pneumonia, it is generally considered to be a disease of older people. A pleural effusion may occur for a variety of reasons. This, too, tends to affect older people.
Causes of pleurisy
Viruses are a common cause of pleurisy. They may cause the pleural membranes to become inflamed and sore in the same way as they affect the membrane of the nose when a person has a cold. Like any other sort of viral infection, pleurisy can occur in small epidemics.
The symptoms of this type of pleurisy are painful chest muscles and pain on breathing. The condition usually settles down without treatment and does not give rise to complications.
Bacteria can also produce pleurisy, although they usually do this as a result of underlying pneumonia. As infection spreads through the lung tissue, it eventually leads to inflammation of the outer surface of the lung. This inflammation then leads to the symptoms of pleurisy.
Bacteria can cause pleurisy in tuberculosis, a disease that is again on the increaseâ€”because of AIDS. It causes a big pleural effusion, and painful breathing so typical of many sorts of pleurisy is not nearly as common in cases related to tuberculosis.
Another common cause of pleural effusion is cancer. Lung cancer as well as cancer from other parts of the body can spread to the pleura. If the pleura is involved, the cancer usually is inoperable.
Occasionally, a pleural effusion turns out to be due to neither an infection nor a tumor, but some other disease. For example, disease that set up a general level of inflammation in the body as result of disturbances in the body’s immune system can cause a pleural effusion. One such disease is called systemic lupus erythematosus.
There is also a very rare hereditary disease that occurs almost exclusively in Armenian and Sephardic Jewish families. It is called familial Mediterranean fever, and it involves repeated attacks of inflammation in all the membranes of the lung as well as in the peritoneum (the membrane that covers the wall of the abdomen; and the pericardium (the membrane that surrounds the heart).
Perhaps the most serious pleural problem is called pulmonary embolism. In this condition, a clot— which may have formed in the leg, for exampleâ€”breaks off, travels through the heart, and gets stuck in the lung. This may cause typical pleural pain, since affected area of the lung becomes inflamed and the inflammation spreads to the pleura. Pulmonary embolisms can be fatal, but if a definite diagnosis has been made, doctors can prescribe anticoagulant drugs to stop further clots from forming.
Symptoms and diagnosis of pleurisy
The main symptom of pleurisy is sudden pain in the chest, made worse with deep breathing, coughing, and chest movement. Pain may be referred to areas away from the site of origin, such as the shoulder, lower chest, neck, or abdomen, which can be confused with intra abdominal disease. If sufficient pleural fluid accumulates, it can compress the underlying lung, causing rapid or difficult breathing.
Pleurisy is easily diagnosed when the characteristic pleuritic pain occurs. A pleural friction rub is diagnostic but may be transient in nature. Chest radiographs are useful to demonstrate pleural fluid. Analysis of the pleural fluid when present is the most helpful diagnostic test in establishing a diagnosis in most cases of pleurisy. This is done using a procedure called Thoracentesis, in which a fine needle is inserted into the chest to reach the pleural space and extract fluid.
Treatment of pleurisy
The pain of pleurisy is controlled with acetaminophen, non-steroidal anti-inflammatory drugs, or occasionally with narcotics, depending on the severity of the pain. Treatment of the underlying cause of pleurisy is essential. Bacterial pneumonia is treated with antibiotics. Viral infections are usually self-limiting and do not require medication other than symptomatic relief.