What condition is characterized by a buildup of fluid in the pleural cavity?

Pleural effusion is characterized by the accumulation of fluid in the pleural cavity, which is the space between the two layers of pleura surrounding the lungs. This condition can impede normal breathing by inhibiting lung expansion. The fluid buildup may occur due to various reasons, including heart failure, infection, malignancy, or inflammation. As the pleural space becomes filled with excessive fluid, it can lead to symptoms such as shortness of breath, chest pain, and cough. Diagnosis typically involves imaging studies such as a chest X-ray or ultrasound, and treatment may require therapeutic procedures like thoracentesis to remove the fluid.

Other conditions, such as pneumothorax and hemothorax, involve different types of fluid or air in the pleural cavity. Pneumothorax involves air in the pleural space, leading to lung collapse, while hemothorax involves the presence of blood in that space. Chest tube insertion is a procedure used to manage conditions like pleural effusion, pneumothorax, or hemothorax, but it is not a condition itself. Therefore, pleural effusion is the correct answer as it specifically refers to the buildup of fluid in the pleural cavity.