Hemothorax in Cats
 
Hemothorax is the medical term used to identify a condition in which blood has collected in the chest cavity, or thorax. This condition may occur suddenly or over a long period of time, and it can occur for a variety of reasons. There does not appear to be a particular age, gender, or breed of cat that is more predisposed to this condition than another.
 
Symptoms and Types
 
Acute onset:

Symptoms of decreased blood volume usually occur before sufficient blood volume accumulates in the pleural space (lining of the chest cavity)