Spontaneous pneumothorax secondary to reactive bronchopneumopathy in a dog

Abstract

An 8-year-old 38-kg (84-lb) castrated male German Shepherd Dog cross was evaluated because of respiratory distress secondary to pneumothorax (detected radio-graphically prior to referral). CT of the thorax confirmed the presence of pneumothorax and revealed pulmonary blebs without evidence of infiltrative pulmonary changes. A tentative diagnosis of primary spontaneous pneumothorax was made. Exploratory median sternotomy revealed emphysematous changes along the margins of all lung lobes, with the ventral margins of the left cranial, right cranial, and right middle lung lobes most affected. Partial lobectomies of the ventral aspects of these lobes were performed. Histologic examination of tissue samples from the lung lobes revealed diffuse smooth muscle hypertrophy of the terminal and respiratory bronchioles with moderate numbers of peribronchiolar eosinophils. Mucus plugs and mucous cell metaplasia within the airway epithelium were also evident. After surgery, clinical signs resolved and the dog was discharged from the hospital 2 days later. Eight months after surgery, the dog developed a mild cough, and treatment with prednisolone (tapering dosage starting at 0.5 mg/kg [0.023 mg/lb], PO, q 12 h) was initiated. Dosage reduction resulted in recurrence of coughing; however, with continued prednisolone treatment at a dosage of 0.5 mg/kg, PO, once daily, the dog was not coughing at 10 months after surgery. Reactive bronchopneumopathy should be included as a differential diagnosis for spontaneous pneumothorax in dogs.