α1-antitrypsin deficiency causing persistent pleural effusion and multilobar alveolar emphysema in a young dog

Pavlos G Doulidis^1*Carolina Frizzo-Ramos²Christof Bertram³Olivia M. Grünzweil⁴Sibylle Maria Kneissl⁴Brigitte Degasperi⁵Reinhard A Hirt¹Iwan Anton Burgener¹Nicole Luckschander¹

• ¹Clinical Unit of Internal Medicine, Department for Small Animals and Horses, University of Veterinary Medicine Vienna, Vienna, Austria
• ²Clinical Unit of Anesthesiology and Perioperative Intensive Care, Department for Companion Animals and Horses, University of Veterinary Medicine, Vienna, Austria., Vienna, Austria
• ³Institute of Pathology, University of Veterinary Medicine, Vienna, Austria., Vienna, Austria
• ⁴Diagnostic Imaging, Department for Companion Animals and Horses, University of Veterinary Medicine, Vienna, Austria., Vienna, Austria
• ⁵Small Animal Surgery, Department of Companion Animals and Horses, University of Veterinary Medicine, Vienna, Austria, Vienna, Austria

Alpha-1 antitrypsin deficiency (A1ATD) is a rare genetic condition in both humans and animals, caused by mutations in the SERPINA1 gene, leading to reduced or absent production of alpha-1 antitrypsin (A1AT). This case report describes a 3-year-old male dog presenting with persistent pleural effusion, chronic non-productive coughing, and respiratory distress. Despite extensive diagnostic evaluation, including computed tomography (CT), a definitive diagnosis of A1ATD was reached only after histopathological examination of lung tissue, which revealed acinar emphysema characterized by destruction of alveolar walls. Serum A1AT levels were undetectable, confirming the diagnosis. The absence of liver involvement aligned with the lung-predominant phenotype described in human A1ATD. This is the first reported case of A1ATD-associated emphysema and pleural effusion in a dog, emphasizing the need for further research into its pathophysiology, diagnosis, and management in canine patients.