Pleurisy · What Is It, Causes, Symptoms, and More

Pleurisy, also known as pleuritis, occurs when the pleura, or the thin layers of membrane that surround the lungs (i.e., visceral pleura) and the internal chest cavity (i.e., parietal pleura), become inflamed. 

In between the two layers of pleura is the pleural space, or the pleural cavity.  Usually, there is a small amount of fluid in the pleural cavity that allows the two pleural membranes to glide past each other without any friction when the lungs expand during breathing. With pleurisy, the inflamed membranes rub up against each other instead of gliding past, which can cause sharp or stabbing chest pain and shortness of breath. 

Pleurisy may be an indication of a serious disorder, such as atelectasis, pleural effusion, or empyema. Atelectasis occurs when parts of an individual’s lungs are collapsed and do not expand while breathing as they typically should. A pleural effusion occurs when there is a buildup of fluid in the pleural cavity, while an empyema occurs when there is a buildup of pus in the pleural cavity. Due to the significance of these potential underlying conditions, seeking prompt medical attention for pleurisy and adhering to a proper course of treatment is crucial for positive outcomes.

While there are many causes of pleurisy, viral infection is the most common cause. Infections caused by viruses, such as the influenza virus, can result in infections of the lungs and, ultimately, pleurisy. Other viruses that may lead to development of pleurisy include adenovirus, coxsackieviruses, cytomegalovirus,  Epstein-Barr virus, parainfluenza virus, and respiratory syncytial virus. In addition to viral infections, other common origins of pleurisy include bacterial infections, inflammatory conditions, pulmonary conditions, cardiac conditions, and medication side effects. 

More specifically, bacterial pneumonia, a respiratory infection that can result in inflammation of the air sacs in the lungs, and tuberculosis, a serious bacterial disease that typically infects the lungs, can prompt pleurisy. 

Inflammatory conditions that can bring about pleurisy include systemic lupus erythematosus (SLE), rheumatoid arthritis, and Sjögren syndrome. SLE is a multisystem inflammatory disease that can lead to chronic inflammation of many organs, including the kidneys, joints and lungs. Rheumatoid arthritis is a condition that typically causes inflammation of the joints but can also cause inflammation elsewhere in the body. Finally, Sjögren’s syndrome is marked by the inflammatory destruction of the lacrimal and salivary glands, which secrete lubrication for the eyes and mouth, respectively. 

Various pulmonary conditions may also cause pleurisy. These include pneumothorax, which is marked by a collapsed lung; asbestosis, a lung disease resulting from long term inhalation of asbestos; mesothelioma, a malignancy that may also occur as a result of asbestos exposure; and pulmonary embolism, which occurs when there are blood clots or an obstruction in the artery that supplies blood to the lungs. 

Additionally, pleurisy may develop from cardiac conditions, like a heart attack (i.e., myocardial infarction) or an aortic dissection, which is a tear in the aortic wall. Cardiac surgery is another origin of pleurisy. 

Finally, certain medications can produce pleurisy as a side effect. These include certain chemotherapy medications (e.g., methotrexate and bleomycin), antiarrhythmic medications (e.g., amiodarone and procainamide), tuberculosis medication (e.g., ionazid), and high blood pressure medications (e.g., hydralazine). 

A thorough review of symptoms and physical examination are the first steps in diagnosing pleurisy. This is often followed by additional diagnostic procedures and imaging to help determine the location and cause of the inflammation. 

Blood tests may be ordered to determine if an individual has an existing infection, as well as to identify the particular cause of the infection. Blood tests can also indicate potential inflammatory disorders. In order to visualize the lungs and confirm the inflammation, chest X-rays are typically conducted. A decubitus chest X-ray, a specific type of chest X-ray that is taken while the individual lies on their side, can be used to identify if fluid has built up in the pleura of the lungs. Depending on the results of the X-ray, a computed tomography (CT) scan may be performed to get a more detailed view of the inflamed lung. An ultrasound can also assist in visualizing the lungs by using high frequency sound waves to identify possible inflammation and fluid buildup.

Pleurisy can last anywhere from a few days to several weeks, depending on the underlying cause. If the cause is less serious and can be fully treated, as in the case of an infection, the individual is likely to recover more quickly. On the other hand, if the cause is more serious and harder to treat (e.g., mesothelioma), recovery may take longer.