Thoracic Trauma: Penetrating Injuries and Thoracic Bite Wounds

Thoracic trauma can be classified by the aetiology of the trauma and by its location. The major aetiological classes are blunt trauma, such as caused in a motor vehicle accident or fall from a height, or penetrating trauma, for example due to ballistic injury or impalement. Bite wound trauma causes both crushing injury and penetrating injury, with inoculation of bacteria into devitalised tissue, and therefore is best considered separately.

The most common cause of thoracic trauma seen in cats and dogs is as a result of motor vehicle accidents. Animals can present with a range of pathologies including pneumothorax, haemothorax, pulmonary contusions and diaphragmatic rupture, whilst injury to the conducting airways or great vessels is uncommon. In general, blunt trauma to the chest causes rupture of marginal alveoli and air leakage into the pleural space. The majority of animals can be managed conservatively with needle thoracocentesis or placement of a thoracostomy tube. The use of small-bore wire-guided chest drains is ideal for this use (Valtolina & Adamantos 2009). True thoracic surgery is rarely indicated following blunt thoracic trauma. However, one notable exception is for management of tracheal or bronchial avulsion injuries in the cat (White & Burton 2000; White & Oakley 2001; Schmierer et al, 2014). This occurs due to traction of the trachea from the fixed point of the carina. Clinical signs are usually not detected until 10 days or more following trauma, since airway continuity is initially maintained by a peritracheal pseudomembrane, with respiratory obstruction only developing when the avulsed ends begin to stenose. Recent publications are limited to case reports which describe anaesthesia techniques used for safe ventilation and the use of computed tomography to better characterise the nature of the injury prior to thoracotomy (Schmierer et al, 2014; Sayre et al 2015). Diaphragmatic herniorhaphy is not addressed in this presentation.

Bite wounds represent up to 10% of all traumatic injury cases admitted to a veterinary emergency service in one study (Kolata et al 1974 JAVMA). Male entire dogs that weigh less than 10 Kg are the most likely victims (Shamir et al, 2002). Animals generally present with multiple bite wounds and the number, location and severity of the bite [...]