Pneumothorax describes air within the chest cavity, but outside of the lungs.
The chest area surrounding the lungs is a vacuum, allowing the easy expansion of the lungs during inhalation. Unwanted air can enter this vacuum in two ways. In the first instance, a puncture wound through the chest wall and skin will allow air to be drawn into the vacuum. Secondly, trauma to the lungs can allow air to escape into the area around them. Fractured (broken) ribs can be sharp and puncture lung tissue, allowing air to leak from the lungs into the surrounding chest cavity. Whatever the mechanism, once air enters the free area of the chest, the lungs are no longer supported by the vacuum and will collapse to some degree.
Generally, pneumothorax will develop following trauma to the chest, punctures causing an opening through the chest wall, or a tearing of the lung tissue itself. Bite wounds and automobile accidents are frequent causes. Unless both sides of the chest cavity are damaged, usually only the right or the left lung is collapsed.
What are the symptoms?
The cat will have difficulty breathing, especially on inhalation. One will notice a rapid, shallow, difficult breathing rhythm. If the breathing is severely limited, the tongue, gums, and lips may also appear blue. In severe wounds, the lungs may actually be exposed to the outside. Regardless of the degree of injury, a cat with pneumothorax will be restless and try to lie in an upright position on the sternum. This position is known as sternal recumbency. This upright position helps the cat more easily inflate the lungs.
What are the risks?
The risk associated with a pneumothorax depends largely on the extent of the trauma. A simple puncture wound from a tooth may cause little air to enter the chest, while more severe lacerations can be immediately life threatening.
Do not assume that a small puncture wound in the skin is not serious. Underlying muscles are often severely traumatized and ribs may also be broken. Additionally, chest wounds frequently are contaminated, which can result in serious lung and chest infections. Have all chest wounds, no matter how slight, examined by a veterinarian at once, as they are potentially life threatening.
What is the management?
The symptoms will not be alleviated until the chest wall is surgically repaired by closing the opening to the outside. Once the wound is repaired, the excess air is withdrawn from the chest cavity using a needle and syringe or a special valve. Antibiotics are generally administered to combat bacterial infections.