Acute breathing distress linked to adrenal tumor in adult dog

Abstract

A 16-year-old castrated male shih tzu dog was brought to the emergency service because of an acute (24 h) history of gagging, coughing, and lethargy. Physical examination revealed dyspnea concurrent with diffuse, bilateral, pulmonary crackles and wheezes. Oxygen saturation, measured with a pulse oximeter, was < 95%. Thoracic radiographs revealed a multifocal alveolar pattern superimposed over a diffuse interstitial pattern with normal heart size. The dog continued to be dyspneic despite oxygen therapy. In accordance with the radiographic findings, further supportive care was recommended. Due to the unknown prognosis and financial constraints, the owner elected humane euthanasia. Necropsy confirmed a pheochromocytoma and lung changes without evidence of congestive heart failure. Findings were consistent with diffuse alveolar damage. These findings correlated with the dog's clinical diagnosis of acute respiratory distress syndrome (ARDS). No other disease processes associated with ARDS were identified. The purpose of this case report is to describe an unusual presentation of ARDS likely associated with a pheochromocytoma and confirmed by necropsy. Acute respiratory distress syndrome associated with a pheochromocytoma has been described in medical literature but has never been reported in veterinary medicine. Key clinical message: Pheochromocytomas should be added to the list of risk factors associated with ARDS in dogs. Dogs with a suspected diagnosis of pheochromocytoma whose owners elect against surgical removal should be closely monitored for an acute onset of respiratory distress, which could suggest the development of ARDS.