By John C. Wolf, D.O.
Associate Professor of Family Medicine
Ohio University College of Osteopathic Medicine

"PLEURAL REACTION" ALWAYS REQUIRES TESTS TO FIND EXACT CAUSE

Question: What does it mean when you are told you have pleural reaction?

Answer: The pleura is a double-layered covering over the lungs, but I think a brief anatomy lesson is in order so you will understand why the pleura is important.

As you know, the 12 pairs of ribs and their connections to the spine form the chest structure. These bones are interconnected by many muscles that move the ribs. The most important muscle of respiration is the abdominal diaphragm. This muscle connects to the lower ribs and separates the chest from the abdomen and the organs it contains. In quiet respiration the rhythmic contraction and relaxation of the diaphragm pumps air through the trachea, or windpipe as it is often called, and into and then out of the lungs. Other muscles attached to the ribs are called upon to contract with the diaphragm and, thereby, pump a maximal amount of air through the lungs when vigorous exercise demands the deepest breathing.

With this background, I can now explain that smooth pleural membranes cover both the outside of the lungs and the inside of the chest. These membranes produce a small amount of “lubricating fluid” that keeps the two surfaces wet and slippery. This helps the respiratory process proceed smoothly by allowing the lungs to slide easily and independently from the chest wall movement.

A “pleural reaction” is either an inflammation of the pleura or an increased accumulation of pleural fluid. When inflammation occurs, breathing produces pleural movement and rubbing that causes pain. This form of pleural reaction is also called pleurisy. When extra fluid is present, the pleural reaction may be called a pleural effusion. The terminology does get confusing, doesn’t it?

A pleural reaction is actually a symptom that can result from several disorders. The most common one, particularly when there is pain present, is pneumonia. The pneumonia may be caused by either a bacteria or a virus, and the cause determines what treatment may be of benefit. Basically, bacterial pneumonia with pleurisy or effusion responds to antibiotics. At our current stage of medical science, viral pneumonia with pleurisy is treated with pain medicine and oxygen, if needed. If you are otherwise healthy, this usually buys the time needed for your immune system to overcome the virus.

A pleural reaction can also result from infection of the pleura. TB is the most common organism that does this, but there are other less frequently encountered bacterial, fungal and viral ones, too.
The accumulation of pleural fluid always makes your doctor think about cancer. Common cancers that produce this type of fluid accumulation are those that originate in the lung or that metastasize (spread) from another organ to the lung.

Some generalized disorders can lead to a pleural reaction. Rheumatoid arthritis and lupus erythematosus are the two most common culprits in this class.

Being told that you have a pleural reaction actually means two things:
* you definitely are ill, and
* more tests are in order.

Certainly a chest X-ray will be needed and probably a CT scan of your chest will also be ordered. It is also quite common to require a sample of the pleural fluid for laboratory testing. Without at least these tests, your doctor won’t be able to tell if your pleural reaction is due to an annoying but less serious condition, or if a life-threatening disorder is causing it.

"Family Medicine" is a weekly column. To submit questions, write to John C. Wolf, D.O., Ohio University College of Osteopathic Medicine, P.O. Box 110, Athens, Ohio 45701. Past columns are available online at http://www.FamilyMedicineNews.org.