EXPRESS: Developmental lung disease with associated pulmonary hypertension in a Sphynx kitten

Case Summary: This case report describes the clinical presentation, diagnostic findings, and clinicopathologic features consistent with developmental lung disease (DLD) and pulmonary hypertension (PH) in a 3-month-old, Sphynx munchkin kitten. The kitten was originally referred for episodes of respiratory distress unresponsive to medical management consisting of diuretics, antibiotics, and corticosteroids. Echocardiography was consistent with a high probability of PH of a non-cardiac etiology. Baseline blood work, thoracic radiographs, thoracic CT with triphasic angiography, and a bronchoalveolar lavage were performed. Thoracic CT revealed diffuse ground-glass opacity with bronchiolectasis and distention of the pulmonary artery and branches. The bronchoalveolar lavage identified an equal distribution of non-degenerative neutrophils and macrophages with erythrophagocytosis and no overt neoplastic cells or infectious organisms appreciated. The kitten was humanely euthanized due to lack of an identifiable treatable etiology and poor prognosis. Histopathological findings were most consistent with DLD with diffuse acinar underdevelopment and vascular changes including pulmonary capillary hemangiomatosis, findings not previously reported in the feline DLD literature. Relevance and novel information: There is a paucity of literature describing DLD and its potential to cause PH in cats. A comprehensive diagnostic evaluation ultimately including histologic examination is needed to reach a diagnosis of DLD. In the presence of PH in a young kitten without any identifiable primary cardiac or respiratory cause, pulmonary thromboembolism, or cardiac parasites, a DLD should be considered.