The use of tracheal wash and bronchoalveolar lavage in the clinical examination of coughing horses

Abstract

Our hypothesis is that coughing horses have airway inflammation. Fifty horses – 36 coughing (Co Group)and 14 control (C Group) – of different gender, age, and function were evaluated. Physical and endoscopicexaminations, and cytological analyses of tracheal wash (TW) and bronchoalveolar lavage (BAL) fluids wereundertaken. Higher grades of tracheal mucus were observed in coughing horses. TW fluid neutrophil countwas higher (46.4% ± 30.8% vs. 19.5% ± 22.9%, p=0.003) in the Co group than the C group. In BAL fluid,neutrophil count was higher in the Co group than in the C group (30.3% ± 27.3% vs. 5.0% ± 4.2%, p=0.001,respectively). BAL fluid cytological profile compatible with inflammatory airway disease (IAD), recurrentairway obstruction (RAO), and normal were evidenced in 14 (38.9%), 17 (47.2%), and 5 (13.9%) of theevaluated coughing horses. IAD was diagnosed in 6 horses of the C group. Cough is a clinical sign of airwayinflammation in horses.

Associations between clinical signs, endoscopic and cytological findings in equine bronchoalveolar lavage samples

“…Horses with an anamnesis of coughing, or a combination of coughing and poor performance, had a significantly higher TMS and a higher percentage of BAL neutrophils than horses reported solely with poor performance. Several studies have found associations between coughing, lower airway neutrophilia and TMS in both sport horses and racehorses (Almeida et al, 2015;Bedenice et al, 2008;Bosshard and Gerber, 2014;Wasko et al, 2011). In the present study, poor performance was found to have significantly lower TMS than the groups with complaints of coughing; this can be explained by the multifactorial nature of poor performance (Ellis et al, 2022), as well as uncertainties regarding both the poor performance definition and owner reliability (Richard et al, 2010;Salz et al, 2016).…”

“…Besides owner reported clinical signs, endoscopic examination including scoring of tracheal mucus (Gerber et al, 2004b) and bronchoalveolar lavage (BAL) is considered the gold standard in EA diagnostics (Bond et al, 2018;Couetil et al, 2016). For example, tracheal mucus score is reported to increase with both MEA and SEA cases, poor performance and coughing, and is thus a reliable, important parameter of the endoscopic examination (Almeida et al, 2015;Cardwell et al, 2011;Gerber et al, 2004a;Holcombe et al, 2006;Koblinger et al, 2011;Pirie et al, 2016;Widmer et al, 2009). Tracheal mucus score between MEA subtypes has been evaluated sparsely, and an increased amount of mucus has been found associated only with the mixed MEA subtype (Nolen-Walston et al, 2013).…”