What is pleurisy?

Pleurisy, or pleuritis, is an acute or chronic inflammation of the pleura.

The pleura is a thin membrane that covers the entire surface of the lungs and continues to line the inner surface of the chest wall (which includes the ribs and their intercostal muscles).

As we breathe, the pleura covering the lungs (visceral pleura) slides over the pleura lining the inner surface of the chest wall and diaphragm (parietal pleura), aided by a small, normal amount of pleural fluid that acts as a lubricant.

Pleural fluid is produced and absorbed by the pleura. When there is an increase in production, a decrease in absorption, or both (in a situation of pleural inflammation), pleural effusion occurs.

Causas

A pleurisia pode ser causada por tuberculose, neoplasias malignas, infecções virais e bacterianas, colagenoses e vasculites (doenças reumatológicas), após lesão cardíaca, embolia pulmonar, uremia (insuficiência renal), pancreatite e exposição ao amianto (mineral muito utilizado no passado para fabricação de isolantes térmicos, elétricos e acústicos).

Symptoms

The most common symptoms are: chest pain (on the affected side), chest pain that worsens with deep inhalation (caused by friction between the inflamed visceral and parietal pleura or by inflammation of the parietal pleura itself, which contains many nerves), dry cough, and shortness of breath.

Diagnosis

The diagnosis of the cause of pleurisy depends on the symptoms, clinical evaluation with blood tests, and criteria from the analysis of pleural fluid (if there is enough to sample), and may require a biopsy of the parietal pleura.

Diagnostic thoracentesis involves puncturing and collecting pleural fluid to be sent for laboratory analysis. It can also be used to drain the pleural effusion and serve as part of the treatment (therapeutic or evacuative thoracentesis).

In some cases, a biopsy of the parietal pleura is necessary for diagnosis. This can be done through needle biopsy or via video-assisted thoracoscopy (a minimally invasive surgery using a video scope to perform the biopsy under direct visualization of the pleura, also known as pleuroscopy). The biopsy removes a fragment of the parietal pleura, which is then sent for microscopic examination to determine the cause of pleurisy.

Treatments

The treatment of pleurisy depends on the amount of pleural fluid, the symptoms, and the underlying cause. In addition to clinical treatment (using specific medications for each case), invasive procedures may be required.

When pleurisy is associated with a pleural effusion of significant volume, it usually requires therapeutic thoracentesis and pleural drainage as the initial treatment. However, if these options are not indicated early or if the condition worsens, more invasive treatments may be necessary.

Pleural infections resulting from complicated pneumonia (parapneumonic effusion) or contamination from adjacent organs (such as post-surgical effusion or pancreatitis) may lead to the formation of loculations (fluid pockets), transformation into pleural empyema (pus in the pleural space), and sepsis (widespread infection).

Therapeutic thoracentesis and pleural drainage are used in the early stages of pleural effusion. As the pleural infection progresses, the fluid may become loculated and thicker, requiring video-assisted thoracoscopy (or video-pleuroscopy) for mechanical cleaning of the pleural cavity.

Pulmonary decortication may also be necessary when the thickened fluid hardens and encapsulates the lung. This surgical procedure removes the thick fluid, loculations, and the capsule from the lung surface, allowing the lung to expand and return to its original shape and size.

Regarding pleural neoplasms, pleural metastases from tumors in other organs (such as the lungs or breasts) are more common, but there are also tumors that originate in the pleura, such as mesothelioma. Treatment of metastatic neoplastic pleural effusions typically involves: therapeutic thoracentesis, pleural drainage, and pleurodesis in cases of recurrent effusions (those that return after thoracentesis).

For primary pleural tumors, various treatments are available depending on the tumor presentation: therapeutic thoracentesis, pleural drainage, pleurodesis, pleurectomy (surgical removal of the pleura), and pleuropneumonectomy (surgical removal of the pleura and adjacent organs such as the lung and diaphragm).

By the Einstein Editorial Board