The Management of Spontaneous Pneumothorax in the Dog

Pneumothorax is a condition where air accumulates in the pleural space resulting in collapse of lung lobes. Spontaneous pneumothorax occurs without trauma or an iatrogenic cause and originates in most cases in the lung parenchyma, trachea or bronchi. In patients with primary spontaneous pneumothorax no preceding clinical symptoms are recognized. Patients with secondary pneumothorax might have pulmonary diseases, such as bacterial pneumonia, pulmonary abscesses, or neoplasia. The most common cause of spontaneous pneumothorax is pulmonary blebs or bullae. Patients tend to be large breed dogs or dogs with a deep-chested conformation.
Blebs are defined as accumulations of air within the layers of the visceral pleura, and appear as small bubbles on the surface of the lung. Bullae are air-filled spaces within the lung parenchyma, that form out of confluence of adjacent alveoli. Bullae can be small or very large. Animals with a spontaneous pneumothorax will present with dyspnea without stridor.

Management of the dyspneic patient 

During emergency clinical examination (ABC protocol) cardiac insufficiency as a cause for dyspnea is ruled out. Special attention should be paid to the auscultation and percussion of the thoracic cavity. If a clinical diagnosis of pneumothorax is made, life saving thinneedle thoracocentesis can be performed in the upper one-third part of the thorax with the animal in standing position, in the areas where normal lung auscultation is absent. Lateral and dorsoventral radiographs are made to confirm the diagnosis, to investigate the localization and extension of the pneumothorax, and to evaluate the effect of thoracocentesis. Underlying pulmonary disease sometimes is revealed on X-rays in patients with spontaneous pneumothorax without previous clinical signs. Evaluations of the use of computertomography (CT) in the identification of underlying lung lesions suggest that CT probably is better than plain radiography. [...]