Steroid‐responsive idiopathic interstitial lung disease in two dogs

Two dogs had a history of persistent pyrexia, reduced exercise tolerance, inappetence and coughing and failed to respond to repeated courses of antibiotics. Clinical examination detected adventitious lung sounds, pyrexia and submandibular lymphadenopathy. Haematology revealed an inflammatory leucogram. Both dogs had radiological abnormalities consistent with a multifocal interstitial lung pattern. CT performed in one dog had characteristic changes of cryptogenic organising pneumonia (COP), an extremely rare idiopathic interstitial lung disease. Findings included several parenchymal bands, multifocal patchy ground‐glass opacities and multifocal subpleural and peribronchial hyperattenuating poorly defined nodular opacities throughout the lungs. Bronchoalveolar lavage revealed a sterile suppurative exudate, excluding eosinophilic bronchopneumopathy. There was rapid resolution of clinical and radiological signs, with corticosteroids and relapse in one dog after discontinuation of steroids supporting the diagnosis of this rare condition. Lung biopsy, which was not performed in either case, is definitive but considered invasive with major complications reported including death.