Congenital Lobar Emphysema and Tension Pneumothorax in a Dog

Abstract

Abstract. Congenital lobar emphysema (CLE) and tension pneumothorax (TPT) are rarely reported in dogs. A case of CLE of the right middle lung lobe predisposing to air trapping, alveolar hyperinflation, and pleural rupture resulting in fatal spontaneous TPT in a 6-month-old mixed breed dog is described. The unique alteration of ''bloat line'' was observed in this case in addition to compressive atelectasis of all other lung lobes and lack of negative pressure within the thoracic cavity, signifying markedly elevated intrathoracic pressure. Bronchial cartilage hypoplasia and bronchiectasis were confirmed microscopically, which likely led to abnormal dynamic collapse of bronchi during expiration, consequentially leading to increased intrapulmonary pressure, bullous emphysema, and pleural rupture resulting in TPT. TPT consequent to CLE may therefore be considered one of the potential causes of sudden death in young dogs without overt clinical illness.

Dynamic cervical lung herniation causing dysphagia in a puppy

“…The most common cause of CLE in veterinary literature is air-trapping secondary to bronchial cartilage dysplasia, hypoplasia or aplasia, resulting in dynamic collapse (Voorhout and others 1986, Billet and Sharpe 2002, Gopalakrishnan and Stevenson 2007, Ruth and others 2010). In people, the condition has been reported to arise from bronchial mucomembranous folds, bronchial valves, aberrant vessels, segmental bronchomalacia or other diseases or anomalies resulting in bronchial obstruction (Mitchell and Nykamp 2006).…”

“…The right middle lung lobe is most commonly affected (Voorhout and others 1986). Canine patients typically present with progressive dyspnoea or cough, however, one case in the veterinary literature resulted in sudden death due to secondary alveolar rupture and tension pneumothorax (Gopalakrishnan and Stevenson 2007). …”

“…CLE has been described in dogs radiographically as lobar hyperinflation with evidence of pulmonary vessels visible to the lobe margin, often accompanied by a contralateral mediastinal shift, caudal displacement of the diaphragm, thoracic cavity enlargement, atelectasis of unaffected lobes and possible pneumothorax (Voorhout and others 1986, Billet and Sharpe 2002, Gopalakrishnan and Stevenson 2007). Cervical herniation was not appreciated in the patient's thoracic radiographs, but evidence supportive of lobar emphysema was present.…”

Fatal pneumothorax in a dog caused by a lesion resembling congenital pulmonary airway malformation (CPAM) of children

“…It is possible that some reported canine cases of CLE may, in fact, represent CPAM-like lesions. Among the CLE reports listed above, two describe histological features that are suggestive of CPAM type 2 (Gopalakrishnan and Stevenson 2007) or type 4 (Matsumoto and others 2004). It may be that these were cases of CPAM-like lesions that were interpreted to be CLE, or that forms of pulmonary disease that share features of both diseases exist in dogs.…”

“…CLE is characterised by overinflation or hyperplasia of alveoli, typically within a single lung lobe. This condition leads to emphysema and pneumothorax and is most commonly seen in young animals (Herrtage and Clarke 1985, Voorhout and others 1986, Amis and others 1987, Billet and Sharpe 2002, Stephens and others 2002, Matsumoto and others 2004, Gopalakrishnan and Stevenson 2007, Moon and others 2007, Ruth and others 2011, Yun and others 2016). …”