An inflammation of the mid-chest area is usually caused by a bacterial infection or a fungus. It’s rare in cats, but in severe cases it may be life-threatening. It is also likely to spread, infecting the bloodstream.
Abscesses sometimes develop and the short vein (called the cranial vena cava in animals) that carries deoxygenated blood from the upper half of the body to the heart's right atrium may become infected. These abscesses can cut off the flow of blood to the heart, resulting in death.
Cats often try to eat and swallow inedible things, often causing blockage in the esophagus. This is followed by drooling, gagging, difficulty swallowing, and vomiting — the usual signals for blockage. These and other signals may be depend on the location of the foreign object, the degree to which the esophagus is obstructed and the length of time of the blockage.
A partial obstruction, for instance, may allow fluids to pass, but not food. If the obstruction has been there for an extended period of time, the cat may refuse to eat, lose weight and/or become more tired. The foreign object may puncture the esophagus, resulting in an abscess, inflammation of the chest cavity, pneumonia, or abnormal breathing. Even after the foreign object has been removed or regurgitated, pneumonia may develop.
Another possible cause of mediastinitis is a blow to the neck or chest, or a wound to those areas.
Tests of various kinds will be conducted to rule out a range of possible causes for the symptoms; among these:
A type of instrument that is used to look inside the body
The tube that extends from the mouth to the stomach
The whole system involved in digestion from mouth to anus
The process of removing tissue to examine it, usually for medical reasons.
The superior chamber in an animal's heart.
A localized infection, usually a lesion filled with pus. Can be large or small in size.