Pleurisy

The pleura is a thin membrane covering the inner surface of the chest wall and the organs within the thoracic cavity (such as the lungs and mediastinum). It consists of two layers, forming a closed cavity. Under normal conditions, a small amount of fluid exists in the space between the two pleural layers, acting as a lubricant during respiratory movements. When various pathogenic factors invade the pleura, leading to a series of inflammatory reactions, it is called pleurisy. Based on the inducing factors, pleurisy is classified into infectious pleurisy, neoplastic pleurisy, autoimmune disease-related pleurisy, and pleurisy caused by other etiologies.