What condition results from blood pooling in the pleural space?

Blood pooling in the pleural space is specifically referred to as a hemothorax. This condition occurs when blood accumulates in the pleural cavity, which can result from trauma, surgery, or certain medical conditions. The presence of blood in this space can lead to difficulty breathing, chest pain, and decreased oxygenation as it compromises lung expansion. Hemothorax is often diagnosed through imaging studies, such as a chest X-ray or CT scan, and may require procedures like chest tube insertion or thoracotomy to evacuate the blood and alleviate symptoms.

The other conditions mentioned do not involve blood pooling in the pleural space. Hematemesis refers to vomiting blood, pleurisy is inflammation of the pleura, often causing chest pain during breathing without blood accumulation, and pneumonia is an infection of the lungs that leads to fluid accumulation from inflammatory processes, not specifically blood.