Overview of the pleura:
Pleura is the protective layer which covers the lungs and can be described as a large membrane which in-folds over itself to create a double layer of which the outermost layer is given the name parietal pleura and the layer closer to the lungs given the name visceral pleura. In between the two pleural layers is the pleural space which in its normal health will be lubricated by very small amount of fluid. This lubrication will allow the two surfaces to move over each other during breathing and therefore will support the expansion of the lungs efficiently.
Mechanism of a pleural rub:
In certain instances, the lubrication between the two pleural surfaces will disappear or would become inadequate thus leading to a friction. These frictional movements will lead to a grating or scraping noise when the lung movements take place and It will be audible when listening to the chest using a stethoscope. The characteristic sound which emanates from such frictional forces between the two pleural layers is termed as a ‘pleural rub’ and it is considered a sign indicating possible changes that has taken place in the pleural space due to several possible underlying problems.
Causes of this condition:
When considering possible causes for a pleural rub, lung infections such as pneumonia, pneumothorax as well as certain conditions which can give rise to a pleuritis or inflammation of the pleural layers can be highlighted.
Recognition of a pleural rub:
For clinicians, the recognition of a pleural rub can be a challenge unless for a person with good clinical experience. In order to improve the recognition of the pleural rub the doctor may ask the patient to take deep breathes as this can emphasize the grating noise more than it does with normal breathing.
Another challenge faced by the clinicians is to differentiate a pleural rub with a pericardial rub, which occurs in the same manner between the surfaces of the pericardial space around the heart. Thus, the means of differentiating would be to ask the patient to hold his or her breat for few seconds which will make the pleural rub to disappear whereas a pericardial rub will continue as the heart will be beating continuously.
Further investigations:
When a clinician detects a pleural rub, they will want to investigate the patient further more and this will include a detailed history, examination, blood chemical analysis, imaging studies as well as certain other investigative methods to arrive at a definitive diagnosis.
Treatment of a pleural rub:
Following identification of the underlying disease problem, the treatment strategies will most often involve antibiotics and anti inflammatory agents as the process of friction between the two pleural layers are most often inflammatory in nature.
