Pneumothorax.

Pneumothorax may be classified as open or closed and as traumatic, spontaneous, or iatrogenic. The most common cause of pneumothorax is thoracic trauma. Spontaneous pneumothorax is often a result of bullous emphysema, and iatrogenic pneumothorax is an important complication of procedures involving the thoracic cavity. Most animals present with tachypnea, tachycardia, respiratory distress, and anxiety. Radiography and thoracocentesis are useful diagnostic aids. Traumatic and iatrogenic pneumothorax are commonly treated with thoracocentesis or thoracostomy tube placement. Spontaneous pneumothorax usually requires surgical resection of the affected lobe(s). The prognosis for traumatic pneumothorax is excellent if there are no other life-threatening injuries; for spontaneous pneumothorax, the prognosis depends on the underlying cause and method of treatment. The prognosis for iatrogenic pneumothorax is considered good.Pneumothorax is classified as open or closed and according to the causative mechanism. Open pneumothorax results from a penetrating thoracic injury that permits entry of air into the chest, while closed pneumothorax is the accumulation of air originating from the respiratory system within the pleural space. In some cases, the air may come from both sources (e.g., severe thoracic bite wounds with lung punctures).