A case of pneumothorax is when air enters the thorax from the outside, or through a rupture in the lower airways.
Air inside the thorax is consumes precious space. Once the air is inside, it acts as a weight on the lungs and impairs their inflation during inhalation. The severity of the symptoms depends on the extent of the conceived injury and the amount of air inside the thorax. Affected dogs show mild to severe breathing difficulties, and possibly cyanotic (blue) gums and mucosa due to decreased oxygen intake. In order to facilitate air-intake, animals often assume a spread-leg standing position in order to make use of their abdominal-muscles to help them breathe. In the case of a tension pneumothorax, the animal’s condition worsens rapidly.
An open pneumothorax, a condition where air is entering through the thoracic wall, is usually caused by blunt trauma, stabs or cuts. Since the pressure inside the thorax is lower than on pressure on the outside, an inward flow is created when the thorax is pierced. A closed pneumothorax is caused by injury to lung tissue. As a result of injury, while breathing, air is allowed to “leak” into the chest. The lung can rupture as a complication of acute or chronic pulmonary diseases, after accidents or infiltration with tumors. A complication of both conditions can result in a tension pneumothorax. In a tension pneumothorax, the lesion becomes a one-way-valve through which air can enter the thorax, but is prevented from exiting. As a result, inhaled air becomes trapped inside the thorax and pressure on the lungs increases with every breath.
The trapped air can be detected by an x-ray of the thorax. The most important part of treatment for pneumothorax is to ensure the supply of oxygen, which requires that the patient be hospitalized. If possible, the punctuating injury is closed surgically. The dog has to be kept in a quiet environment and excitation must by all means be absolutely avoided. Smaller ruptures may seal after a few days of intensive care. In such cases the prognosis is good. Healing should be monitored closely and chest x-rays should be taken at regular intervals to ensure that no renewed opening of the lesion has occurred.
If you suspect that your animal is suffering from pneumothorax, consult your vet immediately. Try to calm and sooth your dog as much as possible and try to limit agitation during transport.