Clinical, Bronchoscopic, Histopathologic, Diagnostic Imaging and Arterial Oxygenation Findings in West Highland White Terriers with Idiopathic Pulmonary Fibrosis

Background: Idiopathic pulmonary fibrosis (IPF) is a chronic, interstitial lung disease primarily affecting mainly West Highland white terriers (WHWTs).
Objective: To describe the clinicopathological and diagnostic imaging features in WHWTs with IPF.
Animals: Twelve WHWTs with IPF and 14 healthy control WHWTs.
Method: Prospective study. Clinical signs and findings of physical examination, blood and arterial blood gas analysesvalues, radiography, high resolution computed tomography (HRCT), bronchoscopy and bronchoalveolar lavage (BAL) of IPF dogs were obtained and compared with controls. Histopathological changes in IPF dogs were evaluateddescribed.
Results: MThe mean PaO2 was significantly lower in IPF (mean ± SD, 65.5 mmHg ± SD 15.4 mmHg) than in controls (99.1 ± 7.8 mmHg), pP<0.001). The alveolar-arterial oxygen gradient (P[(A-a])O2) was significantly higher in IPF (50.1 ± 17.3 mmHg) than in controls (17.5 ± 4.9 mmHg), pP<0.001). In HRCT, ground glass opacity (GGO) was detected in all IPF dogs, traction bronchiectasis in 4four, and honeycombing in 1one. Bronchoscopic airway changes were noted in all IPF dogs. BAL fluid (BALF) total cell count (TCC), the numbers, but not the percentages, of macrophages, neutrophils, and mast cells were increased. OIn histopathology, multifocal or diffuse interstitial fibrosis, type II pneumocyte hyperplasia, prominent intra-alveolar macrophages, distortion of alveolar architecture and emphysematous change were detected.
Conclusion and Clinical Importance: IPF causes substantial hypoxemia. In HRCT, GGO is a consistent finding. IPF dogs have concurrent airway changes, and an increase in BALF TCC.