What does "pleurisy" mean and what is a pleural effusion?

Pleurisy, also called pleuritis, is inflammation of the pleura, the thin double-layered membrane surrounding the lungs and lining the chest cavity. The term combines pleur meaning pleura and itis or isy meaning inflammation. Pleurisy causes sharp chest pain that worsens with breathing. A pleural effusion is an abnormal accumulation of fluid in the pleural space between the two layers of the membrane. Effusion comes from the Latin for pouring out. Small effusions may be asymptomatic, while large ones compress the lung and cause dyspnea. ---